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Li Y, Shetty AC, Lon C, Spring M, Saunders DL, Fukuda MM, Hien TT, Pukrittayakamee S, Fairhurst RM, Dondorp AM, Plowe CV, O’Connor TD, Takala-Harrison S, Stewart K. Detecting geospatial patterns of Plasmodium falciparum parasite migration in Cambodia using optimized estimated effective migration surfaces. Int J Health Geogr 2020; 19:13. [PMID: 32276636 PMCID: PMC7149848 DOI: 10.1186/s12942-020-00207-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 04/01/2020] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Understanding the genetic structure of natural populations provides insight into the demographic and adaptive processes that have affected those populations. Such information, particularly when integrated with geospatial data, can have translational applications for a variety of fields, including public health. Estimated effective migration surfaces (EEMS) is an approach that allows visualization of the spatial patterns in genomic data to understand population structure and migration. In this study, we developed a workflow to optimize the resolution of spatial grids used to generate EEMS migration maps and applied this optimized workflow to estimate migration of Plasmodium falciparum in Cambodia and bordering regions of Thailand and Vietnam. METHODS The optimal density of EEMS grids was determined based on a new workflow created using density clustering to define genomic clusters and the spatial distance between genomic clusters. Topological skeletons were used to capture the spatial distribution for each genomic cluster and to determine the EEMS grid density; i.e., both genomic and spatial clustering were used to guide the optimization of EEMS grids. Model accuracy for migration estimates using the optimized workflow was tested and compared to grid resolutions selected without the optimized workflow. As a test case, the optimized workflow was applied to genomic data generated from P. falciparum sampled in Cambodia and bordering regions, and migration maps were compared to estimates of malaria endemicity, as well as geographic properties of the study area, as a means of validating observed migration patterns. RESULTS Optimized grids displayed both high model accuracy and reduced computing time compared to grid densities selected in an unguided manner. In addition, EEMS migration maps generated for P. falciparum using the optimized grid corresponded to estimates of malaria endemicity and geographic properties of the study region that might be expected to impact malaria parasite migration, supporting the validity of the observed migration patterns. CONCLUSIONS Optimized grids reduce spatial uncertainty in the EEMS contours that can result from user-defined parameters, such as the resolution of the spatial grid used in the model. This workflow will be useful to a broad range of EEMS users as it can be applied to analyses involving other organisms of interest and geographic areas.
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Affiliation(s)
- Yao Li
- Center for Geospatial Information Science, Department of Geographical Sciences, University of Maryland, College Park, 20742 MD USA
| | - Amol C. Shetty
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, 21201 MD USA
| | - Chanthap Lon
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Michele Spring
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - David L. Saunders
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Mark M. Fukuda
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Tran Tinh Hien
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | | | - Arjen M. Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Bangkok, Thailand
| | | | - Timothy D. O’Connor
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, 21201 MD USA
| | - Shannon Takala-Harrison
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, 21201 MD USA
| | - Kathleen Stewart
- Center for Geospatial Information Science, Department of Geographical Sciences, University of Maryland, College Park, 20742 MD USA
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Surendra H, Supargiyono, Ahmad RA, Kusumasari RA, Rahayujati TB, Damayanti SY, Tetteh KKA, Chitnis C, Stresman G, Cook J, Drakeley C. Using health facility-based serological surveillance to predict receptive areas at risk of malaria outbreaks in elimination areas. BMC Med 2020; 18:9. [PMID: 31987052 PMCID: PMC6986103 DOI: 10.1186/s12916-019-1482-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 12/09/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND In order to improve malaria burden estimates in low transmission settings, more sensitive tools and efficient sampling strategies are required. This study evaluated the use of serological measures from repeated health facility-based cross-sectional surveys to investigate Plasmodium falciparum and Plasmodium vivax transmission dynamics in an area nearing elimination in Indonesia. METHODS Quarterly surveys were conducted in eight public health facilities in Kulon Progo District, Indonesia, from May 2017 to April 2018. Demographic data were collected from all clinic patients and their companions, with household coordinates collected using participatory mapping methods. In addition to standard microscopy tests, bead-based serological assays were performed on finger-prick bloodspot samples from 9453 people. Seroconversion rates (SCR, i.e. the proportion of people in the population who are expected to seroconvert per year) were estimated by fitting a simple reversible catalytic model to seroprevalence data. Mixed effects logistic regression was used to examine factors associated with malaria exposure, and spatial analysis was performed to identify areas with clustering of high antibody responses. RESULTS Parasite prevalence by microscopy was extremely low (0.06% (95% confidence interval 0.03-0.14, n = 6) and 0 for P. vivax and P. falciparum, respectively). However, spatial analysis of P. vivax antibody responses identified high-risk areas that were subsequently the site of a P. vivax outbreak in August 2017 (62 cases detected through passive and reactive detection systems). These areas overlapped with P. falciparum high-risk areas and were detected in each survey. General low transmission was confirmed by the SCR estimated from a pool of the four surveys in people aged 15 years old and under (0.020 (95% confidence interval 0.017-0.024) and 0.005 (95% confidence interval 0.003-0.008) for P. vivax and P. falciparum, respectively). The SCR estimates in those over 15 years old were 0.066 (95% confidence interval 0.041-0.105) and 0.032 (95% confidence interval 0.015-0.069) for P. vivax and P. falciparum, respectively. CONCLUSIONS These findings demonstrate the potential use of health facility-based serological surveillance to better identify and target areas still receptive to malaria in an elimination setting. Further implementation research is needed to enable integration of these methods with existing surveillance systems.
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Affiliation(s)
- Henry Surendra
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Jl. Medika, Yogyakarta, 55281 Indonesia
| | - Supargiyono
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Jl. Medika, Yogyakarta, 55281 Indonesia
- Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Sekip Utara, Yogyakarta, 55281 Indonesia
| | - Riris A. Ahmad
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Jl. Medika, Yogyakarta, 55281 Indonesia
- Department of Biostatistics, Epidemiology and Population Health, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Sekip Utara, Yogyakarta, 55281 Indonesia
| | - Rizqiani A. Kusumasari
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Jl. Medika, Yogyakarta, 55281 Indonesia
- Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Sekip Utara, Yogyakarta, 55281 Indonesia
| | | | - Siska Y. Damayanti
- District Health Office of Kulon Progo, Jln. Suparman No 1, Wates, 55611 Indonesia
| | - Kevin K. A. Tetteh
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
| | | | - Gillian Stresman
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
| | - Jackie Cook
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
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53
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Assebe LF, Kwete XJ, Wang D, Liu L, Norheim OF, Jbaily A, Verguet S, Johansson KA, Tolla MT. Health gains and financial risk protection afforded by public financing of selected malaria interventions in Ethiopia: an extended cost-effectiveness analysis. Malar J 2020; 19:41. [PMID: 31973694 PMCID: PMC6979328 DOI: 10.1186/s12936-020-3103-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/07/2020] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a public health burden and a major cause for morbidity and mortality in Ethiopia. Malaria also places a substantial financial burden on families and Ethiopia’s national economy. Economic evaluations, with evidence on equity and financial risk protection (FRP), are therefore essential to support decision-making for policymakers to identify best buys amongst possible malaria interventions. The aim of this study is to estimate the expected health and FRP benefits of universal public financing of key malaria interventions in Ethiopia. Methods Using extended cost-effectiveness analysis (ECEA), the potential health and FRP benefits were estimated, and their distributions across socio-economic groups, of publicly financing a 10% coverage increase in artemisinin-based combination therapy (ACT), long-lasting insecticide-treated bed nets (LLIN), indoor residual spraying (IRS), and malaria vaccine (hypothetical). Results ACT, LLIN, IRS, and vaccine would avert 358, 188, 107 and 38 deaths, respectively, each year at a net government cost of $5.7, 16.5, 32.6, and 5.1 million, respectively. The annual cost of implementing IRS would be two times higher than that of the LLIN interventions, and would be the main driver of the total costs. The averted deaths would be mainly concentrated in the poorest two income quintiles. The four interventions would eliminate about $4,627,800 of private health expenditures, and the poorest income quintiles would see the greatest FRP benefits. ACT and LLINs would have the largest impact on malaria-related deaths averted and FRP benefits. Conclusions ACT, LLIN, IRS, and vaccine interventions would bring large health and financial benefits to the poorest households in Ethiopia.
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Affiliation(s)
- Lelisa Fekadu Assebe
- Department of Global Public Health and Primary Care Medicine, University of Bergen, Bergen, Norway
| | - Xiaoxiao Jiang Kwete
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Dan Wang
- School of Public Policy and Administration, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Lingrui Liu
- Department of Health Policy and Management, Yale School of Public Health, New Haven, CT, USA.,Global Health Leadership Initiative, Yale University, New Haven, CT, USA
| | - Ole Frithjof Norheim
- Department of Global Public Health and Primary Care Medicine, University of Bergen, Bergen, Norway.,Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Abdulrahman Jbaily
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Stéphane Verguet
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA.
| | - Kjell Arne Johansson
- Department of Global Public Health and Primary Care Medicine, University of Bergen, Bergen, Norway
| | - Mieraf Taddesse Tolla
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
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54
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Phommasone K, van Leth F, Imwong M, Henriques G, Pongvongsa T, Adhikari B, Peto TJ, Promnarate C, Dhorda M, Sirithiranont P, Mukaka M, Peerawaranun P, Day NPJ, Cobelens F, Dondorp AM, Newton PN, White NJ, von Seidlein L, Mayxay M. The use of ultrasensitive quantitative-PCR to assess the impact of primaquine on asymptomatic relapse of Plasmodium vivax infections: a randomized, controlled trial in Lao PDR. Malar J 2020; 19:4. [PMID: 31900172 PMCID: PMC6942400 DOI: 10.1186/s12936-019-3091-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 12/25/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Trials to assess the efficacy of the radical cure of Plasmodium vivax malaria with 8-aminoquinolines require that most post-treatment relapses are identified, but there is no consensus on the optimal duration of follow-up in either symptomatic or asymptomatic vivax malaria. The efficacy of a 14-day course of primaquine on the cumulative incidence of recurrent asymptomatic P. vivax infections detected by ultrasensitive quantitative PCR (uPCR) as a primary endpoint was assessed. METHODS A randomized, placebo-controlled, single-blind trial was conducted in four villages of the Lao PDR during 2016-2018 nested in a larger project evaluating mass drug administrations (MDA) with dihydroartemisinin-piperaquine (DP) and a single low-dose primaquine to clear Plasmodium falciparum infections. In the nested sub-study, eligible participants with mono- or mixed P. vivax infections detected by uPCR were randomized to receive either 14 days of primaquine (0.5 mg/kg/day) or placebo during the last round of MDA (round 3) through directly observed therapy. Participants were checked monthly for 12 months for parasitaemia using uPCR. The primary outcome was cumulative incidence of participants with at least one recurrent episode of P. vivax infection. RESULTS 20 G6PD-normal participants were randomized in each arm. 5 (29%) of 20 participants in the placebo arm experienced asymptomatic, recurrent P. vivax infections, resulting in a cumulative incidence at month 12 of 29%. None of the 20 participants in the intervention arm had recurrent infections (p = 0.047 Fisher's exact test). Participants with recurrent P. vivax infections were found to be parasitaemic for between one and five sequential monthly tests. The median time to recurrence of P. vivax parasitaemia was 178 days (range 62-243 days). CONCLUSIONS A 14-day course of primaquine in addition to a DP-MDA was safe, well-tolerated, and prevented recurrent asymptomatic P. vivax infections. Long follow-up for up to 12 months is required to capture all recurrences following the treatment of asymptomatic vivax infection. To eliminate all malarias in settings where P. vivax is endemic, a full-course of an 8-aminoquinolines should be added to MDA to eliminate all malarias. Trial registration This study was registered with ClinicalTrials.gov under NCT02802813 on 16th June 2016. https://clinicaltrials.gov/ct2/show/NCT02802813.
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Affiliation(s)
- Koukeo Phommasone
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Department of Global Health, Amsterdam University Medical Centers, Location AMC, Amsterdam, The Netherlands
- Amsterdam Institute for Global Health & Development, Amsterdam, The Netherlands
| | - Frank van Leth
- Department of Global Health, Amsterdam University Medical Centers, Location AMC, Amsterdam, The Netherlands
- Amsterdam Institute for Global Health & Development, Amsterdam, The Netherlands
| | - Mallika Imwong
- Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Gisela Henriques
- Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand
| | - Tiengkham Pongvongsa
- Savannakhet Provincial Health Department, Savannakhet, Savannakhet Province, Lao PDR
| | - Bipin Adhikari
- Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Thomas J Peto
- Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | | | - Mehul Dhorda
- Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- WWARN Asia Regional Centre, Mahidol University, Bangkok, Thailand
| | | | - Mavuto Mukaka
- Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | | | - Nicholas P J Day
- Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Frank Cobelens
- Department of Global Health, Amsterdam University Medical Centers, Location AMC, Amsterdam, The Netherlands
- Amsterdam Institute for Global Health & Development, Amsterdam, The Netherlands
| | - Arjen M Dondorp
- Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Nicholas J White
- Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Lorenz von Seidlein
- Mahidol Oxford Research Unit, Mahidol University, Bangkok, Thailand.
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Institute of Research and Education Development, University of Health Sciences, Vientiane, Lao PDR
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55
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Sanann N, Peto TJ, Tripura R, Callery JJ, Nguon C, Bui TM, Nofal SD, von Seidlein L, Lek D, Dondorp AM, Cheah PY, Pell C. Forest work and its implications for malaria elimination: a qualitative study. Malar J 2019; 18:376. [PMID: 31771587 PMCID: PMC6880349 DOI: 10.1186/s12936-019-3008-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 11/16/2019] [Indexed: 11/11/2022] Open
Abstract
Background Over the last 20 years, malaria incidence has decreased across the Greater Mekong Sub-region (GMS) and the emergence of artemisinin resistance has stimulated efforts to accelerate regional elimination. In the GMS, the malaria transmission is focused increasingly in forested zones. This article describes forest-going activities and examines forest workers’ attitudes to and experiences of malaria prevention and control in north-eastern Cambodia. Methods In Stung Treng Province, Cambodia, 19 in-depth interviews were conducted in villages with participants recently diagnosed with uncomplicated falciparum malaria who reported working in forests. Two focus group discussions with respondents’ forest-working peers were held. Interviews and focus groups were audio-recorded transcribed, and translated for thematic analysis. Results Forest work is an essential source of income for respondents. Many combine it with farming, which influences the timing and duration of forest visits. Forest activities include logging and collecting other forest products, particularly malva nuts. Men log year-round, whereas gathering forest products is seasonal and can involve entire families. Forest workers sleep chiefly in unimpregnated hammock nets in make-shift encampments. Respondents are concerned about symptomatic malaria, but unfamiliar with the concept of asymptomatic infection. They view the forest as an area of potential malaria infection and seek to protect themselves from mosquito bites through wearing long-sleeved clothes, using repellents, and lighting fires. Forest workers express a willingness to self-test and self-administer anti-malarials. Conclusions Forest workers’ behaviour and perceptions of risk indicate that improvements are needed to current control measures. There is potential to: better target distribution of impregnated hammock nets; offer curative or presumptive treatment while in forests; and expand access to screening. Establishing the efficacy and feasibility of prophylaxis for forest workers in the GMS is a priority.
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Affiliation(s)
- Nou Sanann
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,University Research Company, Phnom Penh, Cambodia
| | - Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - James J Callery
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chea Nguon
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Thanh Mai Bui
- Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Stephanie D Nofal
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Dysoley Lek
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Phaik Yeong Cheah
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Christopher Pell
- Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands.,Centre for Social Sciences and Global Health, University of Amsterdam, Amsterdam, The Netherlands
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56
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van Eijk AM, Sutton PL, Ramanathapuram L, Sullivan SA, Kanagaraj D, Priya GSL, Ravishankaran S, Asokan A, Sangeetha V, Rao PN, Wassmer SC, Tandel N, Patel A, Desai N, Choubey S, Ali SZ, Barla P, Oraon RR, Mohanty S, Mishra S, Kale S, Bandyopadhyay N, Mallick PK, Huck J, Valecha N, Singh OP, Pradhan K, Singh R, Sharma SK, Srivastava HC, Carlton JM, Eapen A. The burden of submicroscopic and asymptomatic malaria in India revealed from epidemiology studies at three varied transmission sites in India. Sci Rep 2019; 9:17095. [PMID: 31745160 PMCID: PMC6863831 DOI: 10.1038/s41598-019-53386-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 10/31/2019] [Indexed: 01/14/2023] Open
Abstract
Malaria in India, while decreasing, remains a serious public health problem, and the contribution of submicroscopic and asymptomatic infections to its persistence is poorly understood. We conducted community surveys and clinic studies at three sites in India differing in their eco-epidemiologies: Chennai (Tamil Nadu), Nadiad (Gujarat), and Rourkela (Odisha), during 2012-2015. A total of 6,645 subject blood samples were collected for Plasmodium diagnosis by microscopy and PCR, and an extensive clinical questionnaire completed. Malaria prevalence ranged from 3-8% by PCR in community surveys (24 infections in Chennai, 56 in Nadiad, 101 in Rourkela), with Plasmodium vivax dominating in Chennai (70.8%) and Nadiad (67.9%), and Plasmodium falciparum in Rourkela (77.3%). A proportional high burden of asymptomatic and submicroscopic infections was detected in community surveys in Chennai (71% and 71%, respectively, 17 infections for both) and Rourkela (64% and 31%, 65 and 31 infections, respectively). In clinic studies, a proportional high burden of infections was identified as submicroscopic in Rourkela (45%, 42 infections) and Chennai (19%, 42 infections). In the community surveys, anemia and fever were significantly more common among microscopic than submicroscopic infections. Exploratory spatial analysis identified a number of potential malaria hotspots at all three sites. There is a considerable burden of submicroscopic and asymptomatic malaria in malarious regions in India, which may act as a reservoir with implications for malaria elimination strategies.
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Affiliation(s)
- Anna Maria van Eijk
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, 10003, USA
| | - Patrick L Sutton
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, 10003, USA.,GlaxoSmithKline, 5 Moore Drive, PO Box 13398, RTP, Raleigh, NC, 27709-3398, United States
| | - Lalitha Ramanathapuram
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, 10003, USA.,Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Steven A Sullivan
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, 10003, USA
| | - Deena Kanagaraj
- Indian Council of Medical Research - National Institute of Malaria Research, IDVC Field Unit, National Institute of Epidemiology Campus, Ayapakkam, Chennai, Tamil Nadu, India
| | - G Sri Lakshmi Priya
- Indian Council of Medical Research - National Institute of Malaria Research, IDVC Field Unit, National Institute of Epidemiology Campus, Ayapakkam, Chennai, Tamil Nadu, India.,Department of Zoology, Madras Christian College, University of Madras, Tambaram, Chennai, 600 059, India
| | - Sangamithra Ravishankaran
- Indian Council of Medical Research - National Institute of Malaria Research, IDVC Field Unit, National Institute of Epidemiology Campus, Ayapakkam, Chennai, Tamil Nadu, India
| | - Aswin Asokan
- Indian Council of Medical Research - National Institute of Malaria Research, IDVC Field Unit, National Institute of Epidemiology Campus, Ayapakkam, Chennai, Tamil Nadu, India
| | - V Sangeetha
- Indian Council of Medical Research - National Institute of Malaria Research, IDVC Field Unit, National Institute of Epidemiology Campus, Ayapakkam, Chennai, Tamil Nadu, India
| | - Pavitra N Rao
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, 10003, USA
| | - Samuel C Wassmer
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, 10003, USA.,London School of Hygiene and Tropical Medicine, Keppel St, London, WC1E 7HT, United Kingdom
| | - Nikunj Tandel
- Indian Council of Medical Research - National Institute of Malaria Research Field Unit, Civil Hospital, Nadiad, Gujarat, India.,Institute of Science, Nirma University, Gujarat, 382481, India
| | - Ankita Patel
- Indian Council of Medical Research - National Institute of Malaria Research Field Unit, Civil Hospital, Nadiad, Gujarat, India
| | - Nisha Desai
- Indian Council of Medical Research - National Institute of Malaria Research Field Unit, Civil Hospital, Nadiad, Gujarat, India
| | - Sandhya Choubey
- Jigyansha, International Center of Excellence for Malaria Research, Sector 1, Rourkela, Odisha, India
| | - Syed Zeeshan Ali
- Jigyansha, International Center of Excellence for Malaria Research, Sector 1, Rourkela, Odisha, India
| | - Punam Barla
- Jigyansha, International Center of Excellence for Malaria Research, Sector 1, Rourkela, Odisha, India
| | - Rajashri Rani Oraon
- Jigyansha, International Center of Excellence for Malaria Research, Sector 1, Rourkela, Odisha, India
| | - Stuti Mohanty
- Jigyansha, International Center of Excellence for Malaria Research, Sector 1, Rourkela, Odisha, India
| | - Shobhna Mishra
- Indian Council of Medical Research, National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India
| | - Sonal Kale
- Indian Council of Medical Research, National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India
| | - Nabamita Bandyopadhyay
- Indian Council of Medical Research, National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India
| | - Prashant K Mallick
- Indian Council of Medical Research, National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India
| | - Jonathan Huck
- Department of Geography Arthur Lewis Building, The University of Manchester, Manchester, England
| | - Neena Valecha
- Indian Council of Medical Research, National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India
| | - Om P Singh
- Indian Council of Medical Research, National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India
| | - K Pradhan
- Jigyansha, International Center of Excellence for Malaria Research, Sector 1, Rourkela, Odisha, India
| | - Ranvir Singh
- Indian Council of Medical Research - National Institute of Malaria Research Field Unit, Civil Hospital, Nadiad, Gujarat, India
| | - S K Sharma
- Indian Council of Medical Research, National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India
| | - Harish C Srivastava
- Indian Council of Medical Research - National Institute of Malaria Research Field Unit, Civil Hospital, Nadiad, Gujarat, India
| | - Jane M Carlton
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, 10003, USA.
| | - Alex Eapen
- Indian Council of Medical Research - National Institute of Malaria Research, IDVC Field Unit, National Institute of Epidemiology Campus, Ayapakkam, Chennai, Tamil Nadu, India
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57
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Imwong M, Madmanee W, Suwannasin K, Kunasol C, Peto TJ, Tripura R, von Seidlein L, Nguon C, Davoeung C, Day NPJ, Dondorp AM, White NJ. Asymptomatic Natural Human Infections With the Simian Malaria Parasites Plasmodium cynomolgi and Plasmodium knowlesi. J Infect Dis 2019; 219:695-702. [PMID: 30295822 PMCID: PMC6376906 DOI: 10.1093/infdis/jiy519] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In Southeast Asia, Plasmodium knowlesi, a parasite of long-tailed macaques (Macaca fascicularis), is an important cause of human malaria. Plasmodium cynomolgi also commonly infects these monkeys, but only one naturally acquired symptomatic human case has been reported previously. METHODS Malariometric studies involving 5422 subjects (aged 6 months to 65 years) were conducted in 23 villages in Pailin and Battambang, western Cambodia. Parasite detection and genotyping was conducted on blood samples, using high-volume quantitative PCR (uPCR). RESULTS Asymptomatic malaria parasite infections were detected in 1361 of 14732 samples (9.2%). Asymptomatic infections with nonhuman primate malaria parasites were found in 21 individuals living close to forested areas; P. cynomolgi was found in 11, P. knowlesi was found in 8, and P. vivax and P. cynomolgi were both found in 2. Only 2 subjects were female, and 14 were men aged 20-40 years. Geometric mean parasite densities were 3604 parasites/mL in P. cynomolgi infections and 52488 parasites/mL in P. knowlesi infections. All P. cynomolgi isolates had wild-type dihydrofolate reductase genes, in contrast to the very high prevalence of mutations in the human malaria parasites. Asymptomatic reappearance of P. cynomolgi occurred in 2 subjects 3 months after the first infection. CONCLUSIONS Asymptomatic naturally acquired P. cynomolgi and P. knowlesi infections can both occur in humans. CLINICAL TRIALS REGISTRATION NCT01872702.
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Affiliation(s)
- Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Mahidol University, Bangkok, Thailand.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wanassanan Madmanee
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kanokon Suwannasin
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chanon Kunasol
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thomas J Peto
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Rupam Tripura
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Lorenz von Seidlein
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Chea Nguon
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh
| | | | - Nicholas P J Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
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58
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Galatas B, Martí-Soler H, Nhamussua L, Cisteró P, Aide P, Saute F, Menéndez C, Rabinovich NR, Alonso PL, Bassat Q, Mayor A. Dynamics of Afebrile Plasmodium falciparum Infections in Mozambican Men. Clin Infect Dis 2019; 67:1045-1052. [PMID: 29546346 PMCID: PMC6137111 DOI: 10.1093/cid/ciy219] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 03/12/2018] [Indexed: 01/08/2023] Open
Abstract
Background Afebrile Plasmodium falciparum infections usually remain undetected and untreated in the community and could potentially contribute to sustaining local malaria transmission in areas aiming for malaria elimination. Methods Thirty-two men with afebrile P. falciparum infections detected with rapid diagnostic test (RDTs) were followed for 28 days. Kaplan-Meier estimates were computed to estimate probability of parasite positivity and of reducing parasitemia by half of its initial level by day 28. Trends of parasite densities quantified by microscopy and real-time quantitative polymerase chain reaction (qPCR) were assessed using Poisson regression models, and the microscopy-to-qPCR positivity ratio was calculated at each time point. Three survival distributions (Gompertz, Weibull, and gamma) were used to evaluate their strength of fit to the data and to predict the median lifetime of infection. Results The cumulative probability of parasite qPCR positivity by day 28 was 81% (95% confidence interval [CI], 60.2–91.6). Geometric mean parasitemia at recruitment was 516.1 parasites/μL and fell to <100 parasites/μL by day 3, reaching 56.7 parasites/μL on day 28 (P < .001). The ratio of P. falciparum–positive samples by microscopy to qPCR decreased from 0.9 to 0.52 from recruitment to day 28. The best model fit to the data was obtained assuming a Gompertz distribution. Conclusions Afebrile P. falciparum infections detectable by RDT in semi-immune adults fall and stabilize at low-density levels during the first 4 days after detection, suggesting a rapid decline of potential transmissibility in this hidden parasite reservoir. Clincial trials registration NCT02698748
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Affiliation(s)
- Beatriz Galatas
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.,ISGlobal, Barcelona Center for International Health Research, Hospital Clínic-Universitat de Barcelona, Spain
| | - Helena Martí-Soler
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.,ISGlobal, Barcelona Center for International Health Research, Hospital Clínic-Universitat de Barcelona, Spain
| | - Lidia Nhamussua
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
| | - Pau Cisteró
- ISGlobal, Barcelona Center for International Health Research, Hospital Clínic-Universitat de Barcelona, Spain
| | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.,National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Francisco Saute
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
| | - Clara Menéndez
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.,ISGlobal, Barcelona Center for International Health Research, Hospital Clínic-Universitat de Barcelona, Spain
| | - N Regina Rabinovich
- ISGlobal, Barcelona Center for International Health Research, Hospital Clínic-Universitat de Barcelona, Spain.,Harvard T. H. Chan School of Public Health, Boston, Massachusetts
| | - Pedro L Alonso
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.,ISGlobal, Barcelona Center for International Health Research, Hospital Clínic-Universitat de Barcelona, Spain
| | - Quique Bassat
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.,ISGlobal, Barcelona Center for International Health Research, Hospital Clínic-Universitat de Barcelona, Spain.,Catalan Institution for Research and Advanced Studies, Barcelona, Spain
| | - Alfredo Mayor
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.,ISGlobal, Barcelona Center for International Health Research, Hospital Clínic-Universitat de Barcelona, Spain
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Pobsuk N, Suphakun P, Hannongbua S, Nantasenamat C, Choowongkomon K, Gleeson MP. Synthesis, Plasmodium falciparum Inhibitory Activity, Cytotoxicity and Solubility of N2 ,N4 -Disubstituted Quinazoline-2,4-diamines. Med Chem 2019; 15:693-704. [PMID: 30569870 DOI: 10.2174/1573406415666181219100307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 12/10/2018] [Accepted: 12/10/2018] [Indexed: 01/06/2023]
Abstract
BACKGROUND Despite the development of extensive control strategies and treatment options, approximately 200 million malaria cases, leading to approximately 450,000 deaths, were reported in 2015. Due to issue of disease resistance, additional drug development efforts are needed to produce new, more effective treatments. Quinazoline-2,4-diamines were identified as antiparasitic compounds over three decades ago and have remained of interest to date in industry and academia. OBJECTIVE An anti-malarial SAR evaluation of previously unreported N2 ,N4 -disubstituted quinazoline- 2,4-diamines have been undertaken in this study. We have synthesized and evaluated new derivatives against P. falciparum in our attempt to better characterize their biological activity and overall physical properties. METHODS The synthesis of N2 ,N4 -disubstituted quinazoline-2,4-diamines inhibitors is reported along with activities in a radioactive labeled hypoxanthine incorporation assay against the f Plasmodium falciparum (Pf.) K1 strain. In addition, cytotoxicity was determined in the A549 and Vero cell lines using an MTT based. The aqueous solubility of key compounds was assessed at pH 7.4 using a shake flask-based approach. RESULTS We identified compounds 1 and 6p as sub µM inhibitors of P. falciparum, having equivalent anti-malarial activity to Chloroquine. Compounds 1 and 6m are low µM inhibitors of P. falciparum with improved cytotoxicity profiles. Compound 6m displayed the best balance between P. falciparum Inhibitory activity (2 µM) and cytotoxicity, displaying >49 fold selectivity over A549 and Vero cell lines. CONCLUSION Twenty one N2 ,N4 -Disubstituted Quinazoline-2,4-diamines have been prepared in our group and characterized in terms of their antimalarial activity, cytotoxicity and physical properties. Compounds with good activity and reasonable selectivity over mammalian cell lines have been identified. SAR analyses suggest further exploration is are necessary to improve the balance of P. falciparum Inhibitory activity, cytotoxicity and solubility.
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Affiliation(s)
- Nattakarn Pobsuk
- Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Praphasri Suphakun
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Supa Hannongbua
- Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Chanin Nantasenamat
- Center of Data Mining and Biomedical Informatics, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | | | - M Paul Gleeson
- Biomedical Engineering, Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand
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60
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Vantaux A, Samreth R, Piv E, Khim N, Kim S, Berne L, Chy S, Lek D, Siv S, Taylor WR, Ménard D. Contribution to Malaria Transmission of Symptomatic and Asymptomatic Parasite Carriers in Cambodia. J Infect Dis 2019; 217:1561-1568. [PMID: 29394367 DOI: 10.1093/infdis/jiy060] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/26/2018] [Indexed: 12/14/2022] Open
Abstract
Background Eliminating falciparum malaria in Cambodia is a top priority, requiring the implementation of novel tools and strategies to interrupt its transmission. To date, few data are available regarding the contributions to malaria transmission of symptomatic and asymptomatic carriers. Methods Direct-membrane and skin feeding assays (DMFAs, SFAs) were performed, using Anopheles minimus and Anopheles dirus, to determine infectivity of symptomatic falciparum-infected patients and malaria asymptomatic carriers; a subset of the latter were followed up for 2 months to assess their transmission potential. Results By microscopy and real-time polymerase chain reaction, Plasmodium falciparum gametocyte prevalence rates were, respectively, 19.3% (n = 21/109) and 44% (n = 47/109) on day (D) 0 and 17.9% (n = 5/28) and 89.3% (n = 25/28) in recrudescent patients (Drec) (RT-PCR Drec vs D0 P = .002). Falciparum malaria patient infectivity was low on D0 (6.2%; n = 3/48) and in Drec (8.3%; n = 1/12). Direct-membrane feeding assays and SFAs gave similar results. None of the falciparum (n = 0/19) and 3 of 28 Plasmodium vivax asymptomatic carriers were infectious to mosquitoes, including those that were followed up for 2 months. Overall, P. falciparum gametocytemias were low except in a few symptomatic carriers. Conclusions Only symptomatic falciparum malaria patients were infectious to mosquito vectors at baseline and recrudescence, highlighting the need to detect promptly and treat effectively P. falciparum patients.
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Affiliation(s)
- Amélie Vantaux
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Reingsey Samreth
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Eakpor Piv
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Nimol Khim
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Saorin Kim
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Laura Berne
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia.,Xeno Cell Innovations, Plzen, Czech Republic
| | - Sophy Chy
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Dysoley Lek
- National Center for Parasitology, Entomology and Malaria Control Program, Phnom Penh, Cambodia.,School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Sovannaroth Siv
- National Center for Parasitology, Entomology and Malaria Control Program, Phnom Penh, Cambodia
| | - Walter R Taylor
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Didier Ménard
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia.,Unité Biologie des Interactions Hôte-Parasite, Institut Pasteur, Paris, France
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61
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Liew JWK, Mahpot RB, Dzul S, Abdul Razak HAB, Ahmad Shah Azizi NAB, Kamarudin MB, Russell B, Lim KL, de Silva JR, Lim BS, Jelip J, Mudin RNB, Lau YL. Importance of Proactive Malaria Case Surveillance and Management in Malaysia. Am J Trop Med Hyg 2019; 98:1709-1713. [PMID: 29877176 DOI: 10.4269/ajtmh.17-1010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Although Plasmodium vivax infections in Malaysia are usually imported, a significant autochthonous outbreak of vivax malaria was detected in a remote indigenous (Orang Asli) settlement located in northern peninsular Malaysia. Between November 2016 and April 2017, 164 cases of P. vivax infection were detected. Although 83.5% of the vivax cases were identified through passive case detection and contact screening during the first 7 weeks, subsequent mass blood screening (combination of rapid diagnostic tests, blood films, and polymerase chain reaction [PCR]) of the entire settlement (N = 3,757) revealed another 27 P. vivax infections, 19 of which were asymptomatic. The mapped data from this active case detection program was used to direct control efforts resulting in the successful control of the outbreak in this region. This report highlights the importance of proactive case surveillance and timely management of malaria control in Malaysia as it nears malaria elimination.
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Affiliation(s)
- Jonathan Wee Kent Liew
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | | | - Shairah Dzul
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | | | | | | | - Bruce Russell
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Khai Lone Lim
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jeremy Ryan de Silva
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Bing Sheng Lim
- Faculty of Applied Sciences, Tunku Abdul Rahman University College, Kuala Lumpur, Malaysia
| | - Jenarun Jelip
- Disease Control Division, Ministry of Health Malaysia, Putrajaya, Malaysia
| | | | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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62
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Mercado CEG, Lawpoolsri S, Sudathip P, Kaewkungwal J, Khamsiriwatchara A, Pan-Ngum W, Yimsamran S, Lawawirojwong S, Ho K, Ekapirat N, Maude RR, Wiladphaingern J, Carrara VI, Day NPJ, Dondorp AM, Maude RJ. Spatiotemporal epidemiology, environmental correlates, and demography of malaria in Tak Province, Thailand (2012-2015). Malar J 2019; 18:240. [PMID: 31311606 PMCID: PMC6636027 DOI: 10.1186/s12936-019-2871-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 07/06/2019] [Indexed: 12/14/2022] Open
Abstract
Background Tak Province, at the Thai–Myanmar border, is one of three high malaria incidence areas in Thailand. This study aimed to describe and identify possible factors driving the spatiotemporal trends of disease incidence from 2012 to 2015. Methods Climate variables and forest cover were correlated with malaria incidence using Pearson’s r. Statistically significant clusters of high (hot spots) and low (cold spots) annual parasite incidence per 1000 population (API) were identified using Getis-Ord Gi* statistic. Results The total number of confirmed cases declined by 76% from 2012 to 2015 (Plasmodium falciparum by 81%, Plasmodium vivax by 73%). Incidence was highly seasonal with two main annual peaks. Most cases were male (62.75%), ≥ 15 years (56.07%), and of Myanmar (56.64%) or Thai (39.25%) nationality. Median temperature (1- and 2-month lags), average temperature (1- and 2-month lags) and average relative humidity (2- and 3-month lags) correlated positively with monthly total, P. falciparum and P. vivax API. Total rainfall in the same month correlated with API for total cases and P. vivax but not P. falciparum. At sub-district level, percentage forest cover had a low positive correlation with P. falciparum, P. vivax, and total API in most years. There was a decrease in API in most sub-districts for both P. falciparum and P. vivax. Sub-districts with the highest API were in the Tha Song Yang and Umphang Districts along the Thai–Myanmar border. Annual hot spots were mostly in the extreme north and south of the province. Conclusions There has been a large decline in reported clinical malaria from 2012 to 2015 in Tak Province. API was correlated with monthly climate and annual forest cover but these did not account for the trends over time. Ongoing elimination interventions on one or both sides of the border are more likely to have been the cause but it was not possible to assess this due to a lack of suitable data. Two main hot spot areas were identified that could be targeted for intensified elimination activities. Electronic supplementary material The online version of this article (10.1186/s12936-019-2871-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chris Erwin G Mercado
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Saranath Lawpoolsri
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Center of Excellence for Biomedical and Public Health Informatics (BIOPHICS), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Prayuth Sudathip
- Bureau of Vector-borne Diseases (BVBD), Department of Disease Control (DDC), Ministry of Public Health (MOPH), Nonthaburi, Thailand
| | - Jaranit Kaewkungwal
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Center of Excellence for Biomedical and Public Health Informatics (BIOPHICS), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Amnat Khamsiriwatchara
- Center of Excellence for Biomedical and Public Health Informatics (BIOPHICS), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wirichada Pan-Ngum
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Surapon Yimsamran
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Siam Lawawirojwong
- Geo-Informatics and Space Technology Development Agency (GISTDA), Bangkok, Thailand
| | - Kevin Ho
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nattwut Ekapirat
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rapeephan R Maude
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jacher Wiladphaingern
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Shoklo Malaria Research Unit (SMRU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Verena I Carrara
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Shoklo Malaria Research Unit (SMRU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Nicholas P J Day
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Richard J Maude
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Harvard University, Boston, USA
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63
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Zainabadi K, Nyunt MM, Plowe CV. An improved nucleic acid extraction method from dried blood spots for amplification of Plasmodium falciparum kelch13 for detection of artemisinin resistance. Malar J 2019; 18:192. [PMID: 31185976 PMCID: PMC6558694 DOI: 10.1186/s12936-019-2817-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 05/18/2019] [Indexed: 12/15/2022] Open
Abstract
Background Mutational analysis of the Plasmodium falciparum kelch 13 (k13) gene is routinely performed to track the emergence and spread of artemisinin resistance. Surveillance of resistance markers has been impeded by the difficulty of extracting sufficient DNA from low parasite density infections common in low-transmission settings, such as Southeast Asia. This problem can be overcome by collecting large volumes of venous blood. Efficient methods for extracting and amplifying k13 from dried blood spots (DBS) would facilitate resistance surveillance. Methods Methods for k13 amplification from standard Whatman 3MM DBS (stored for 14 days at 28 °C with 80% relative humidity) were optimized by systematically testing different extraction conditions. Conditions that improved parasite DNA recovery as assessed by quantitative polymerase chain reaction (PCR) of 18S rDNA were then tested for their impact on k13 PCR amplification. Results The optimized protocol for amplification of k13 from DBS is markedly more sensitive than standard methods using commercial kits. Using this method, k13 was successfully amplified from laboratory-created DBS samples with parasite densities as low as 500 parasites/mL. Importantly, the method recovers both DNA and RNA, making it compatible with RNA-based ultrasensitive techniques currently in use. Conclusions The optimized DBS protocol should facilitate drug resistance surveillance, especially in low-transmission settings where clinical malaria infections with high parasite densities are rare. Electronic supplementary material The online version of this article (10.1186/s12936-019-2817-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kayvan Zainabadi
- Institute for Global Health, University of Maryland School of Medicine, Baltimore, MD, USA. .,Center for Global Health, Weill Cornell Medicine, New York, NY, USA.
| | - Myaing M Nyunt
- Duke Global Health Institute, Duke University, Durham, NC, USA
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von Seidlein L, Peto TJ, Tripura R, Pell C, Yeung S, Kindermans JM, Dondorp A, Maude R. Novel Approaches to Control Malaria in Forested Areas of Southeast Asia. Trends Parasitol 2019; 35:388-398. [PMID: 31076353 DOI: 10.1016/j.pt.2019.03.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/24/2019] [Accepted: 03/27/2019] [Indexed: 12/27/2022]
Abstract
The emergence and spread of drug resistance in the Greater Mekong Subregion (GMS) have added urgency to accelerate malaria elimination while reducing the treatment options. The remaining foci of malaria transmission are often in forests, where vectors tend to bite during daytime and outdoors, thus reducing the effectiveness of insecticide-treated bed nets. Limited periods of exposure suggest that chemoprophylaxis could be a promising strategy to protect forest workers against malaria. Here we discuss three major questions in optimizing malaria chemoprophylaxis for forest workers: which antimalarial drug regimens are most appropriate, how frequently the chemoprophylaxis should be delivered, and how to motivate forest workers to use, and adhere to, malaria prophylaxis.
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Affiliation(s)
- Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Christopher Pell
- Centre for Social Sciences and Global Health, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
| | - Shunmay Yeung
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - Arjen Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Richard Maude
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
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Jiram AI, Ooi CH, Rubio JM, Hisam S, Karnan G, Sukor NM, Artic MM, Ismail NP, Alias NW. Evidence of asymptomatic submicroscopic malaria in low transmission areas in Belaga district, Kapit division, Sarawak, Malaysia. Malar J 2019; 18:156. [PMID: 31046769 PMCID: PMC6498596 DOI: 10.1186/s12936-019-2786-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/22/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Malaysia has declared its aim to eliminate malaria with a goal of achieving zero local transmission by the year 2020. However, targeting the human reservoir of infection, including those with asymptomatic infection is required to achieve malaria elimination. Diagnosing asymptomatic malaria is not as straightforward due to the obvious lack of clinical manifestations and often subpatent level of parasites. Accurate diagnosis of malaria is important for providing realistic estimates of malaria burden and preventing misinformed interventions. Low levels of parasitaemia acts as silent reservoir of transmission thus remains infectious to susceptible mosquito vectors. Hence, the aim of this study is to investigate the prevalence of asymptomatic submicroscopic malaria (SMM) in the District of Belaga, Sarawak. METHODS In 2013, a total of 1744 dried blood spots (DBS) were obtained from residents of 8 longhouses who appeared healthy. Subsequently, 251 venous blood samples were collected from residents of 2 localities in 2014 based on the highest number of submicroscopic cases from prior findings. Thin and thick blood films were prepared from blood obtained from all participants in this study. Microscopic examination were carried out on all samples and a nested and nested multiplex PCR were performed on samples collected in 2013 and 2014 respectively. RESULTS No malaria parasites were detected in all the Giemsa-stained blood films. However, of the 1744 samples, 29 (1.7%) were positive for Plasmodium vivax by PCR. Additionally, of the 251 samples, the most prevalent mono-infection detected by PCR was Plasmodium falciparum 50 (20%), followed by P. vivax 39 (16%), P. knowlesi 9 (4%), and mixed infections 20 (8%). CONCLUSIONS This research findings conclude evidence of Plasmodium by PCR, among samples previously undetectable by routine blood film microscopic examination, in local ethnic minority who are clinically healthy. SMM in Belaga district is attributed not only to P. vivax, but also to P. falciparum and P. knowlesi. In complementing efforts of programme managers, there is a need to increase surveillance for SMM nationwide to estimate the degree of SMM that warrant measures to block new transmission of malaria.
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Affiliation(s)
- Adela Ida Jiram
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia.
| | - Choo Huck Ooi
- Vector Borne Diseases Section, Sarawak Health Department, Ministry of Health Malaysia, Diplomatik Road, Off Bako Road, Petra Jaya, 93050, Kuching, Sarawak, Malaysia
| | - José Miguel Rubio
- Malaria & Emerging Parasitic Diseases Laboratory, Parasitology Department, National Centre of Microbiology, Instituto de Salud Carlos III (ISCIII), Carretera de Majadahonda - Pozuelo, km. 2,200, Majadahonda, 28220, Madrid, Spain
| | - Shamilah Hisam
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Govindarajoo Karnan
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Nurnadiah Mohd Sukor
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Mohd Mafie Artic
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Nor Parina Ismail
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Nor Wahida Alias
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
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Amaral LC, Robortella DR, Guimarães LFF, Limongi JE, Fontes CJF, Pereira DB, de Brito CFA, Kano FS, de Sousa TN, Carvalho LH. Ribosomal and non-ribosomal PCR targets for the detection of low-density and mixed malaria infections. Malar J 2019; 18:154. [PMID: 31039781 PMCID: PMC6492410 DOI: 10.1186/s12936-019-2781-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 04/13/2019] [Indexed: 01/01/2023] Open
Abstract
Background The unexpected high proportion of submicroscopic malaria infections in areas with low transmission intensity challenges the control and elimination of malaria in the Americas. The current PCR-based assays present limitations as most protocols still rely on amplification of few-copies target gene. Here, the hypothesis was that amplification of different plasmodial targets—ribosomal (18S rRNA) and non-ribosomal multi-copy sequences (Pvr47 for Plasmodium vivax and Pfr364 for Plasmodium falciparum)—could increase the chances of detecting submicroscopic malaria infection. Methods A non-ribosomal real-time PCR assay targeting Pvr47/Pfr364 (NR-qPCR) was established and compared with three additional PCR protocols, two of them based on 18S rRNA gene amplification (Nested-PCR and R-qPCR) and one based on Pvr47/Pfr364 targets (NR-cPCR). The limit of detection of each PCR protocol, at single and artificial mixed P. vivax/P. falciparum infections, was determined by end-point titration curves. Field samples from clinical (n = 110) and subclinical (n = 324) malaria infections were used to evaluate the impact of using multiple molecular targets to detect malaria infections. Results The results demonstrated that an association of ribosomal and non-ribosomal targets did not increase sensitivity to detect submicroscopic malaria infections. Despite of that, artificial mixed-malaria infections demonstrated that the NR-qPCR was the most sensitive protocol to detect low-levels of P. vivax/P. falciparum co-infections. Field studies confirmed that submicroscopic malaria represented a large proportion (up to 77%) of infections among asymptomatic Amazonian residents, with a high proportion of infections (~ 20%) identified only by the NR-qPCR. Conclusions This study presents a new species-specific non-ribosomal PCR assay with potential to identify low-density P. vivax and P. falciparum infections. As the majority of subclinical infections was caused by P. vivax, the commonest form of malaria in the Amazon area, future studies should investigate the potential of Pvr47/Pfr364 to detect mixed-malaria infections in the field. Electronic supplementary material The online version of this article (10.1186/s12936-019-2781-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lara Cotta Amaral
- Instituto René Rachou, Fundação Oswaldo Cruz, FIOCRUZ-MINAS, Belo Horizonte, MG, Brazil
| | - Daniela Rocha Robortella
- Instituto René Rachou, Fundação Oswaldo Cruz, FIOCRUZ-MINAS, Belo Horizonte, MG, Brazil.,Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | | | | | - Dhelio Batista Pereira
- Centro de Pesquisas em Medicina Tropical de Rondônia (CEPEM), Porto Velho, Rondônia, Brazil
| | | | - Flora Satiko Kano
- Instituto René Rachou, Fundação Oswaldo Cruz, FIOCRUZ-MINAS, Belo Horizonte, MG, Brazil
| | - Taís Nóbrega de Sousa
- Instituto René Rachou, Fundação Oswaldo Cruz, FIOCRUZ-MINAS, Belo Horizonte, MG, Brazil.
| | - Luzia Helena Carvalho
- Instituto René Rachou, Fundação Oswaldo Cruz, FIOCRUZ-MINAS, Belo Horizonte, MG, Brazil. .,Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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67
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Parker DM, Tun STT, White LJ, Kajeechiwa L, Thwin MM, Landier J, Chaumeau V, Corbel V, Dondorp AM, von Seidlein L, White NJ, Maude RJ, Nosten F. Potential herd protection against Plasmodium falciparum infections conferred by mass antimalarial drug administrations. eLife 2019; 8:e41023. [PMID: 30990166 PMCID: PMC6467567 DOI: 10.7554/elife.41023] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 03/25/2019] [Indexed: 11/13/2022] Open
Abstract
The global malaria burden has decreased over the last decade and many nations are attempting elimination. Asymptomatic malaria infections are not normally diagnosed or treated, posing a major hurdle for elimination efforts. One solution to this problem is mass drug administration (MDA), with success depending on adequate population participation. Here, we present a detailed spatial and temporal analysis of malaria episodes and asymptomatic infections in four villages undergoing MDA in Myanmar. In this study, individuals from neighborhoods with low MDA adherence had 2.85 times the odds of having a malaria episode post-MDA in comparison to those from high adherence neighborhoods, regardless of individual participation, suggesting a herd effect. High mosquito biting rates, living in a house with someone else with malaria, or having an asymptomatic malaria infection were also predictors of clinical episodes. Spatial clustering of non-adherence to MDA, even in villages with high overall participation, may frustrate elimination efforts.
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Affiliation(s)
- Daniel M Parker
- Department of Population Health and Disease PreventionUniversity of CaliforniaIrvineUnited States
| | - Sai Thein Than Tun
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityNakhon PathomThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited kingdom
| | - Lisa J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityNakhon PathomThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited kingdom
| | - Ladda Kajeechiwa
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityNakhon PathomThailand
| | - May Myo Thwin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityNakhon PathomThailand
| | - Jordi Landier
- Institut de Recherche pour le DéveloppementUniversity of MontpellierMontpellierFrance
| | - Victor Chaumeau
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited kingdom
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityNakhon PathomThailand
- Centre Hospitalier Universitaire de MontpellierMontpellierFrance
- Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle IRD 224-CNRS 5290UM1-UM2, Institut de Recherche pour le Développement (IRD)University of MontpellierMontpellierFrance
| | - Vincent Corbel
- Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle IRD 224-CNRS 5290UM1-UM2, Institut de Recherche pour le Développement (IRD)University of MontpellierMontpellierFrance
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityNakhon PathomThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited kingdom
| | - Lorenz von Seidlein
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityNakhon PathomThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited kingdom
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityNakhon PathomThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited kingdom
| | - Richard J Maude
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityNakhon PathomThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited kingdom
- Harvard TH Chan School of Public HealthHarvard UniversityHarvardUnited States
| | - François Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited kingdom
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityNakhon PathomThailand
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Chaumeau V, Kajeechiwa L, Fustec B, Landier J, Naw Nyo S, Nay Hsel S, Phatharakokordbun P, Kittiphanakun P, Nosten S, Thwin MM, Win Tun S, Wiladphaingern J, Cottrell G, Parker DM, Minh MC, Kwansomboon N, Metaane S, Montazeau C, Kunjanwong K, Sawasdichai S, Andolina C, Ling C, Haohankhunnatham W, Christiensen P, Wanyatip S, Konghahong K, Cerqueira D, Imwong M, Dondorp AM, Chareonviriyaphap T, White NJ, Nosten FH, Corbel V. Contribution of Asymptomatic Plasmodium Infections to the Transmission of Malaria in Kayin State, Myanmar. J Infect Dis 2019; 219:1499-1509. [PMID: 30500927 PMCID: PMC6467188 DOI: 10.1093/infdis/jiy686] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/27/2018] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The objective of mass antimalarial drug administration (MDA) is to eliminate malaria rapidly by eliminating the asymptomatic malaria parasite reservoirs and interrupting transmission. In the Greater Mekong Subregion, where artemisinin-resistant Plasmodium falciparum is now widespread, MDA has been proposed as an elimination accelerator, but the contribution of asymptomatic infections to malaria transmission has been questioned. The impact of MDA on entomological indices has not been characterized previously. METHODS MDA was conducted in 4 villages in Kayin State (Myanmar). Malaria mosquito vectors were captured 3 months before, during, and 3 months after MDA, and their Plasmodium infections were detected by polymerase chain reaction (PCR) analysis. The relationship between the entomological inoculation rate, the malaria prevalence in humans determined by ultrasensitive PCR, and MDA was characterized by generalized estimating equation regression. RESULTS Asymptomatic P. falciparum and Plasmodium vivax infections were cleared by MDA. The P. vivax entomological inoculation rate was reduced by 12.5-fold (95% confidence interval [CI], 1.6-100-fold), but the reservoir of asymptomatic P. vivax infections was reconstituted within 3 months, presumably because of relapses. This was coincident with a 5.3-fold (95% CI, 4.8-6.0-fold) increase in the vector infection rate. CONCLUSION Asymptomatic infections are a major source of malaria transmission in Southeast Asia.
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Affiliation(s)
- Victor Chaumeau
- Centre hospitalier universitaire de Montpellier, Montpellier
- UMR 224 “Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle,” Institut de Recherche pour le Développement, Montpellier
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Ladda Kajeechiwa
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Bénédicte Fustec
- UMR 224 “Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle,” Institut de Recherche pour le Développement, Montpellier
| | - Jordi Landier
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
- Institut de Recherches pour le Développement, Aix Marseille Univ, INSERM, SESSTIM, Marseille
| | - Saw Naw Nyo
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Saw Nay Hsel
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Phabele Phatharakokordbun
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Prapan Kittiphanakun
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Suphak Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - May Myo Thwin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Saw Win Tun
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Jacher Wiladphaingern
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Gilles Cottrell
- UMR 216 “Mère et enfant face aux infections tropicales,” Institut de Recherche pour le Développement, Université Paris Descartes, Paris, France
| | - Daniel M Parker
- Department of Population Health and Disease Prevention, University of California, Irvine
| | - Myo Chit Minh
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Nittpha Kwansomboon
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Selma Metaane
- UMR 224 “Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle,” Institut de Recherche pour le Développement, Montpellier
| | - Céline Montazeau
- UMR 224 “Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle,” Institut de Recherche pour le Développement, Montpellier
| | - Kitti Kunjanwong
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Sunisa Sawasdichai
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Chiara Andolina
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Clare Ling
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Warat Haohankhunnatham
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Peter Christiensen
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Sunaree Wanyatip
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Kamonchanok Konghahong
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
| | - Dominique Cerqueira
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University
| | - Arjen M Dondorp
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University
| | | | - Nicholas J White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University
| | - François H Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Vincent Corbel
- UMR 224 “Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle,” Institut de Recherche pour le Développement, Montpellier
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Nguitragool W, Karl S, White M, Koepfli C, Felger I, Singhasivanon P, Mueller I, Sattabongkot J. Highly heterogeneous residual malaria risk in western Thailand. Int J Parasitol 2019; 49:455-462. [PMID: 30954453 PMCID: PMC6996282 DOI: 10.1016/j.ijpara.2019.01.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 01/21/2019] [Accepted: 01/25/2019] [Indexed: 01/01/2023]
Abstract
There is a highly heterogenous risk of malaria infection among villagers in western Thailand. The molecular force of infection was determined in a low endemic setting. There is a strong correlation between malaria prevalence and the force of infection.
Over the past decades, the malaria burden in Thailand has substantially declined. Most infections now originate from the national border regions. In these areas, the prevalence of asymptomatic infections is still substantial and poses a challenge for the national malaria elimination program. To determine epidemiological parameters as well as risk factors for malaria infection in western Thailand, we carried out a cohort study in Kanchanaburi and Ratchaburi provinces on the Thailand-Myanmar border. Blood samples from 999 local participants were examined for malaria infection every 4 weeks between May 2013 and Jun 2014. Prevalence of Plasmodium falciparum and Plasmodium vivax was determined by quantitative PCR (qPCR) and showed a seasonal variation with values fluctuating from 1.7% to 4.2% for P. vivax and 0% to 1.3% for P. falciparum. Ninety percent of infections were asymptomatic. The annual molecular force of blood-stage infection (molFOB) was estimated by microsatellite genotyping to be 0.24 new infections per person-year for P. vivax and 0.02 new infections per person-year for P. falciparum. The distribution of infections was heterogenous, that is, the vast majority of infections (>80%) were found in a small number of individuals (<8% of the study population) who tested positive at multiple timepoints. Significant risk factors were detected for P. vivax infections, including previous clinical malaria, occupation in agriculture and travel to Myanmar. In contrast, indoor residual spraying was associated with a protection from infection. These findings provide a recent landscape of malaria epidemiology and emphasize the importance of novel strategies to target asymptomatic and imported infections.
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Affiliation(s)
- Wang Nguitragool
- Department of Molecular Tropical Medicine & Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Stephan Karl
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Vector-borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province, Papua New Guinea
| | - Michael White
- Malaria: Parasites and Hosts Unit, Department of Parasites & Insect Vectors, Institute Pasteur, Paris, France
| | - Cristian Koepfli
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Ingrid Felger
- Department of Medical Parasitology and Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland
| | - Pratap Singhasivanon
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ivo Mueller
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Malaria: Parasites and Hosts Unit, Department of Parasites & Insect Vectors, Institute Pasteur, Paris, France.
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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70
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Pell CL, Adhikari B, Myo Thwin M, Kajeechiwa L, Nosten S, Nosten FH, Sahan KM, Smithuis FM, Nguyen TN, Hien TT, Tripura R, Peto TJ, Sanann N, Nguon C, Pongvongsa T, Phommasone K, Mayxay M, Mukaka M, Peerawaranun P, Kaehler N, Cheah PY, Day NPJ, White NJ, Dondorp AM, von Seidlein L. Community engagement, social context and coverage of mass anti-malarial administration: Comparative findings from multi-site research in the Greater Mekong sub-Region. PLoS One 2019; 14:e0214280. [PMID: 30908523 PMCID: PMC6433231 DOI: 10.1371/journal.pone.0214280] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 03/11/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Between 2013 and 2017, targeted malaria elimination (TME), a package of interventions that includes mass drug administration (MDA)-was piloted in communities with reservoirs of asymptomatic P. falciparum across the Greater Mekong sub-Region (GMS). Coverage in target communities is a key determinant of the effectiveness of MDA. Drawing on mixed methods research conducted alongside TME pilot studies, this article examines the impact of the community engagement, local social context and study design on MDA coverage. METHODS AND FINDINGS Qualitative and quantitative data were collected using questionnaire-based surveys, semi-structured and in-depth interviews, focus group discussions, informal conversations, and observations of study activities. Over 1500 respondents were interviewed in Myanmar, Vietnam, Cambodia and Laos. Interview topics included attitudes to malaria and experiences of MDA. Overall coverage of mass anti-malarial administration was high, particularly participation in at least a single round (85%). Familiarity with and concern about malaria prompted participation in MDA; as did awareness of MDA and familiarity with the aim of eliminating malaria. Fear of adverse events and blood draws discouraged people. Hence, community engagement activities sought to address these concerns but their impact was mediated by the trust relationships that study staff could engender in communities. In contexts of weak healthcare infrastructure and (cash) poverty, communities valued the study's ancillary care and the financial compensation. However, coverage did not necessarily decrease in the absence of cash compensation. Community dynamics, affected by politics, village conformity, and household decision-making also affected coverage. CONCLUSIONS The experimental nature of TME presented particular challenges to achieving high coverage. Nonetheless, the findings reflect those from studies of MDA under implementation conditions and offer useful guidance for potential regional roll-out of MDA: it is key to understand target communities and provide appropriate information in tailored ways, using community engagement that engenders trust.
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Affiliation(s)
- Christopher L. Pell
- Amsterdam Institute for Global Health and Development (AIGHD), Amsterdam, The Netherlands
- Centre for Social Science and Global Health, University of Amsterdam, Amsterdam, The Netherlands
| | - Bipin Adhikari
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - May Myo Thwin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Ladda Kajeechiwa
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Suphak Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Francois H. Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Sorbonne Universités, UPMC Univ Paris 06, UPMC UMRS CR7, Paris, France
| | - Kate M. Sahan
- Ethox Centre and Wellcome Centre for Ethics and Humanities, Nuffield Department of Population Health, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Frank M. Smithuis
- Medical Action Myanmar, Yangon, Myanmar
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
| | - Thuy-Nhien Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Asia Programme, Ho Chi Minh City, Vietnam
| | - Tran Tinh Hien
- Oxford University Clinical Research Unit, Wellcome Trust Asia Programme, Ho Chi Minh City, Vietnam
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Thomas J. Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nou Sanann
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chea Nguon
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - Koukeo Phommasone
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Lao PDR
| | - Mayfong Mayxay
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Lao PDR
- Institute of Research and Educational Development, University of Health Sciences, Vientiane, Lao PDR
| | - Mavuto Mukaka
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pimnara Peerawaranun
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nils Kaehler
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Phaik Yeong Cheah
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Ethox Centre and Wellcome Centre for Ethics and Humanities, Nuffield Department of Population Health, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Nicholas P. J. Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas J. White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Arjen M. Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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Geographical heterogeneity in prevalence of subclinical malaria infections at sentinel endemic sites of Myanmar. Parasit Vectors 2019; 12:83. [PMID: 30777127 PMCID: PMC6378722 DOI: 10.1186/s13071-019-3330-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 01/31/2019] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The malaria burden of Myanmar still remains high within the Greater Mekong Subregion of Southeast Asia. An important indicator of progress towards malaria elimination is the prevalence of parasite infections in endemic populations. Information about malaria epidemiology is mostly derived from reports of confirmed acute malaria cases through passive case detection, whereas the prevalence of baseline subclinical malaria infections is much less known. METHODS In this study, cross-sectional surveys were conducted during the rainy season of 2017 in four townships (Bilin, Thabeikkyin, Banmauk and Paletwa) of Myanmar with divergent annual malaria incidences. A total of 1991 volunteers were recruited from local villages and Plasmodium subclinical infections were estimated by light microscopy (LM), rapid diagnostic tests (RDTs) and nested PCR. The nested PCR analysis was performed with a modified pooling strategy that was optimized based on an initial estimate the infection prevalence. RESULTS The overall malaria infection prevalence based on all methods was 13.9% (277/1991) and it differed drastically among the townships, with Paletwa in the western border having the highest infection rate (22.9%) and Thabeikkyin in central Myanmar having the lowest (3.9%). As expected, nested PCR was the most sensitive and identified 226 (11.4%) individuals with parasite infections. Among the parasite species, Plasmodium vivax was the most prevalent in all locations, while Plasmodium falciparum also accounted for 32% of infections in the western township Paletwa. Two RDTs based on the detection of the hrp2 antigen detected a total of 103 P. falciparum infections, and the ultrasensitive RDT detected 20% more P. falciparum infections than the conventional RDT. In contrast, LM missed the majority of the subclinical infections and only identified 14 Plasmodium infections. CONCLUSIONS Cross-sectional surveys identified considerable levels of asymptomatic Plasmodium infections in endemic populations of Myanmar with P. vivax becoming the predominant parasite species. Geographical heterogeneity of subclinical infections calls for active surveillance of parasite infections in endemic areas. The pooling scheme designed for nested PCR analysis offers a more practical strategy for large-scale epidemiological studies of parasite prevalence. Such information is important for decision-makers to put forward a more realistic action plan for malaria elimination.
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von Seidlein L, Peto TJ, Landier J, Nguyen TN, Tripura R, Phommasone K, Pongvongsa T, Lwin KM, Keereecharoen L, Kajeechiwa L, Thwin MM, Parker DM, Wiladphaingern J, Nosten S, Proux S, Corbel V, Tuong-Vy N, Phuc-Nhi TL, Son DH, Huong-Thu PN, Tuyen NTK, Tien NT, Dong LT, Hue DV, Quang HH, Nguon C, Davoeung C, Rekol H, Adhikari B, Henriques G, Phongmany P, Suangkanarat P, Jeeyapant A, Vihokhern B, van der Pluijm RW, Lubell Y, White LJ, Aguas R, Promnarate C, Sirithiranont P, Malleret B, Rénia L, Onsjö C, Chan XH, Chalk J, Miotto O, Patumrat K, Chotivanich K, Hanboonkunupakarn B, Jittmala P, Kaehler N, Cheah PY, Pell C, Dhorda M, Imwong M, Snounou G, Mukaka M, Peerawaranun P, Lee SJ, Simpson JA, Pukrittayakamee S, Singhasivanon P, Grobusch MP, Cobelens F, Smithuis F, Newton PN, Thwaites GE, Day NPJ, Mayxay M, Hien TT, Nosten FH, Dondorp AM, White NJ. The impact of targeted malaria elimination with mass drug administrations on falciparum malaria in Southeast Asia: A cluster randomised trial. PLoS Med 2019; 16:e1002745. [PMID: 30768615 PMCID: PMC6377128 DOI: 10.1371/journal.pmed.1002745] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/15/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The emergence and spread of multidrug-resistant Plasmodium falciparum in the Greater Mekong Subregion (GMS) threatens global malaria elimination efforts. Mass drug administration (MDA), the presumptive antimalarial treatment of an entire population to clear the subclinical parasite reservoir, is a strategy to accelerate malaria elimination. We report a cluster randomised trial to assess the effectiveness of dihydroartemisinin-piperaquine (DP) MDA in reducing falciparum malaria incidence and prevalence in 16 remote village populations in Myanmar, Vietnam, Cambodia, and the Lao People's Democratic Republic, where artemisinin resistance is prevalent. METHODS AND FINDINGS After establishing vector control and community-based case management and following intensive community engagement, we used restricted randomisation within village pairs to select 8 villages to receive early DP MDA and 8 villages as controls for 12 months, after which the control villages received deferred DP MDA. The MDA comprised 3 monthly rounds of 3 daily doses of DP and, except in Cambodia, a single low dose of primaquine. We conducted exhaustive cross-sectional surveys of the entire population of each village at quarterly intervals using ultrasensitive quantitative PCR to detect Plasmodium infections. The study was conducted between May 2013 and July 2017. The investigators randomised 16 villages that had a total of 8,445 residents at the start of the study. Of these 8,445 residents, 4,135 (49%) residents living in 8 villages, plus an additional 288 newcomers to the villages, were randomised to receive early MDA; 3,790 out of the 4,423 (86%) participated in at least 1 MDA round, and 2,520 out of the 4,423 (57%) participated in all 3 rounds. The primary outcome, P. falciparum prevalence by month 3 (M3), fell by 92% (from 5.1% [171/3,340] to 0.4% [12/2,828]) in early MDA villages and by 29% (from 7.2% [246/3,405] to 5.1% [155/3,057]) in control villages. Over the following 9 months, the P. falciparum prevalence increased to 3.3% (96/2,881) in early MDA villages and to 6.1% (128/2,101) in control villages (adjusted incidence rate ratio 0.41 [95% CI 0.20 to 0.84]; p = 0.015). Individual protection was proportional to the number of completed MDA rounds. Of 221 participants with subclinical P. falciparum infections who participated in MDA and could be followed up, 207 (94%) cleared their infections, including 9 of 10 with artemisinin- and piperaquine-resistant infections. The DP MDAs were well tolerated; 6 severe adverse events were detected during the follow-up period, but none was attributable to the intervention. CONCLUSIONS Added to community-based basic malaria control measures, 3 monthly rounds of DP MDA reduced the incidence and prevalence of falciparum malaria over a 1-year period in areas affected by artemisinin resistance. P. falciparum infections returned during the follow-up period as the remaining infections spread and malaria was reintroduced from surrounding areas. Limitations of this study include a relatively small sample of villages, heterogeneity between villages, and mobility of villagers that may have limited the impact of the intervention. These results suggest that, if used as part of a comprehensive, well-organised, and well-resourced elimination programme, DP MDA can be a useful additional tool to accelerate malaria elimination. TRIAL REGISTRATION ClinicalTrials.gov NCT01872702.
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Affiliation(s)
- Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Thomas J. Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jordi Landier
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Institut de Recherche pour le Développement, Aix–Marseille University, INSERM, SESSTIM, Marseille, France
| | - Thuy-Nhien Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Koukeo Phommasone
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
- Amsterdam Institute for Global Health & Development, Amsterdam, The Netherlands
| | - Tiengkham Pongvongsa
- Savannakhet Provincial Health Department, Savannakhet Province, Lao People’s Democratic Republic
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Khin Maung Lwin
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Lilly Keereecharoen
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Ladda Kajeechiwa
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - May Myo Thwin
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Daniel M. Parker
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Department of Population Health and Disease Prevention, University of California, Irvine, Irvine, California, United States of America
| | - Jacher Wiladphaingern
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Suphak Nosten
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Stephane Proux
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Vincent Corbel
- Maladies Infectieuses et Vecteurs: Écologie, Génétique, Evolution et Contrôle, Institut de Recherche pour le Développement, Université Montpellier, Montpellier, France
| | - Nguyen Tuong-Vy
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Truong Le Phuc-Nhi
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Do Hung Son
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Pham Nguyen Huong-Thu
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Nguyen Thi Kim Tuyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Nguyen Thanh Tien
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Le Thanh Dong
- Institute of Malariology, Parasitology, and Entomology, Ho Chi Minh City, Vietnam
| | - Dao Van Hue
- Center for Malariology, Parasitology and Entomology, Ninh Thuan Province, Vietnam
| | - Huynh Hong Quang
- Institute of Malariology, Parasitology, and Entomology, Quy Nhon, Vietnam
| | - Chea Nguon
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - Huy Rekol
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Bipin Adhikari
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Gisela Henriques
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Pathogen Molecular Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Panom Phongmany
- Savannakhet Provincial Health Department, Savannakhet Province, Lao People’s Democratic Republic
| | - Preyanan Suangkanarat
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
| | - Atthanee Jeeyapant
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Benchawan Vihokhern
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rob W. van der Pluijm
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Yoel Lubell
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Lisa J. White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Ricardo Aguas
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Cholrawee Promnarate
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- WWARN Asia Regional Centre, Mahidol University, Bangkok, Thailand
| | - Pasathorn Sirithiranont
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Benoit Malleret
- Department of Microbiology & Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore
| | - Laurent Rénia
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore
| | - Carl Onsjö
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Faculty of Medicine and Health Sciences, Linköping University, Linköping, Linköping, Sweden
| | - Xin Hui Chan
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jeremy Chalk
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Olivo Miotto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Krittaya Patumrat
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kesinee Chotivanich
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Borimas Hanboonkunupakarn
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Podjanee Jittmala
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nils Kaehler
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Phaik Yeong Cheah
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Christopher Pell
- Amsterdam Institute for Global Health & Development, Amsterdam, The Netherlands
| | - Mehul Dhorda
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- WWARN Asia Regional Centre, Mahidol University, Bangkok, Thailand
| | - Mallika Imwong
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Georges Snounou
- CEA–Université Paris Sud 11–INSERM U1184, IDMIT, Direction de la Recherche Fondamentale, Commissariat à l’Énergie Atomique et aux Énergies Alternatives, Fontenay-aux-Roses, France
| | - Mavuto Mukaka
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Pimnara Peerawaranun
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sue J. Lee
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Julie A. Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Sasithon Pukrittayakamee
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Royal Society of Thailand, Bangkok, Thailand
| | - Pratap Singhasivanon
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Martin P. Grobusch
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Frank Cobelens
- Amsterdam Institute for Global Health & Development, Amsterdam, The Netherlands
| | | | - Paul N. Newton
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
| | - Guy E. Thwaites
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Nicholas P. J. Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Mayfong Mayxay
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
- Institute of Research and Education Development, University of Health Sciences, Vientiane, Lao People’s Democratic Republic
| | - Tran Tinh Hien
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Institut de Recherche pour le Développement, Aix–Marseille University, INSERM, SESSTIM, Marseille, France
| | - Francois H. Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Arjen M. Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas J. White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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Nofal SD, Peto TJ, Adhikari B, Tripura R, Callery J, Bui TM, von Seidlein L, Pell C. How can interventions that target forest-goers be tailored to accelerate malaria elimination in the Greater Mekong Subregion? A systematic review of the qualitative literature. Malar J 2019; 18:32. [PMID: 30709399 PMCID: PMC6359845 DOI: 10.1186/s12936-019-2666-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/27/2019] [Indexed: 11/26/2022] Open
Abstract
Background Despite decreases in incidence and related mortality, malaria remains a major public health challenge in the Greater Mekong Sub-region (GMS). The emergence of artemisinin resistance threatens these gains and has prompted efforts to accelerate elimination in the region. In the GMS, transmission now clusters in hotspots along international borders and among high-risk populations, including forest-goers. To eliminate malaria in the region, interventions must target such hard-to-reach populations. This review provides a comprehensive overview of the qualitative research on behaviours and perceptions that influence uptake of and adherence to malaria interventions among forest-goers in the GMS. Methods A systematic search strategy was used to identify relevant sources, including database (OVID SP, PubMed, ISI Web of Knowledge) and bibliographic searches. Relevant findings from qualitative research methods were extracted and thematic analysis undertaken. Results Of 268 sources retrieved in searches twenty-two were reviewed. Most reported studies were conducted in Cambodia (n = 10), and were published after 2014 (n = 16). Four major themes emerged that are particularly relevant to the design of intervention packages targeted at forest-goers: (1) understanding of malaria and perceived risk; (2) preventive measures used when visiting the forest; (3) behaviours that put forest-goers at risk of infection; and, (4) malaria-related treatment seeking. There were notable differences across the reviewed articles that suggest the need for a locally tailored approach. Conclusion A more detailed characterization of forest activities is needed but research on this topic raises methodological challenges. Current vector control measures have limitations, with use of insecticidal-treated nets, hammocks and repellents influenced by the type of forest activities and the characteristics of these measures. In contrast, anti-malarial drugs, for example, as chemoprophylaxis, hold promise but require further evaluation. Electronic supplementary material The online version of this article (10.1186/s12936-019-2666-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stephanie D Nofal
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Bipin Adhikari
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - James Callery
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thanh Mai Bui
- Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Christopher Pell
- Centre for Social Sciences and Global Health, University of Amsterdam, Amsterdam, The Netherlands.,Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
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74
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Vilay P, Nonaka D, Senamonty P, Lao M, Iwagami M, Kobayashi J, Hernandez PM, Phrasisombath K, Kounnavong S, Hongvanthong B, Brey PT, Kano S. Malaria prevalence, knowledge, perception, preventive and treatment behavior among military in Champasak and Attapeu provinces, Lao PDR: a mixed methods study. Trop Med Health 2019; 47:11. [PMID: 30700970 PMCID: PMC6347756 DOI: 10.1186/s41182-019-0138-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/14/2019] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a major health problem in Lao People's Democratic Republic (Lao PDR) with high transmission in remote and forest areas, particularly in the South. The military is at risk of malaria infection especially those deployed in forest areas. This study determined the prevalence of malaria infection and assessed knowledge, perception, and preventive and treatment behavior regarding malaria among military personnel in two southern provinces in Lao PDR. Methods Quantitative and qualitative approaches were undertaken in Champasak and Attapeu provinces in 2017. From 313 military personnel, quantitative data were collected through questionnaire-based interviews and blood samples used for parasite detection by polymerase chain reaction (PCR). Qualitative data were collected through 7 focus group discussions and 17 in-depth interviews among 49 military personnel. Fisher's exact test and Mann-Whitney U test were used to assess the association between malaria infection and participant characteristics. Content analysis for qualitative data was performed to explore perception and treatment behaviors regarding malaria. Results The prevalence of malaria infection was 11.2% (Plasmodium falciparum: 1.3%, Plasmodium vivax: 9.3% and mixed infections: 0.6%). Many participants understood that malaria is transmitted through mosquito bites, although they did not necessarily know the name of vector mosquitoes (Anopheles). Surprisingly, more than a half also believed that malaria is transmitted through drinking stream water. One-third of the participants used long-lasting insecticidal nets. Due to limited supply, participants were often unable to use mosquito repellent and coils when necessary. Because participants were unable to receive timely diagnosis and appropriate treatment for malaria in their camps, they commonly practiced self-treatment using antibiotics, painkillers, and/or traditional medicines. They only go to a healthcare facility through their supervisor if their conditions worsen. Conclusions The prevalence of symptomatic and asymptomatic malaria was conspicuous among military in forest areas. Many participants believed that malaria is transmitted not only by mosquito bites but also from drinking stream water. Preventive equipment was often insufficient. Self-treatment was practiced before referring to healthcare facility. To further prevent military from contracting malaria, the National Malaria Control Program and military body should provide adequate and suitable health education, protective equipment, and on-site malaria case management.
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Affiliation(s)
- Phoutnalong Vilay
- 1Department of Global Health, Graduate School of Health Sciences, University of the Ryukyus, 207 Uehara-cho, Okinawa, 903-0215 Japan.,2Center of Malariology, Parasitology and Entomology, Ministry of Health, Vientiane, Lao PDR.,SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR
| | - Daisuke Nonaka
- 1Department of Global Health, Graduate School of Health Sciences, University of the Ryukyus, 207 Uehara-cho, Okinawa, 903-0215 Japan.,SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR
| | - Phosadeth Senamonty
- Military Institute of Diseases Prevention, Department of Military Medical, Ministry of Defense, Vientiane, Lao PDR
| | - Malayvanh Lao
- Military Institute of Diseases Prevention, Department of Military Medical, Ministry of Defense, Vientiane, Lao PDR
| | - Moritoshi Iwagami
- SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR.,5Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655 Japan.,6Institut Pasteur du Laos, Ministry of Health, Vientiane, Lao PDR
| | - Jun Kobayashi
- 1Department of Global Health, Graduate School of Health Sciences, University of the Ryukyus, 207 Uehara-cho, Okinawa, 903-0215 Japan.,SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR
| | - Paul Michael Hernandez
- 1Department of Global Health, Graduate School of Health Sciences, University of the Ryukyus, 207 Uehara-cho, Okinawa, 903-0215 Japan.,7Department of Environmental and Occupational Health, College of Public Health, University of the Philippines Manila, 625 Pedro Gil Street, Ermita, 1000 Manila, Philippines
| | | | - Sengchanh Kounnavong
- SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR.,9Lao Tropical and Public Health Institute, Ministry of Health, Vientiane, Lao PDR
| | - Bouasy Hongvanthong
- 2Center of Malariology, Parasitology and Entomology, Ministry of Health, Vientiane, Lao PDR.,SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR
| | - Paul T Brey
- SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR.,6Institut Pasteur du Laos, Ministry of Health, Vientiane, Lao PDR
| | - Shigeyuki Kano
- SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR.,5Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655 Japan
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75
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Peto TJ, Tripura R, Davoeung C, Nguon C, Nou S, Heng C, Kunthea P, Adhikari B, Lim R, James N, Pell C, Cheah PY. Reflections on a Community Engagement Strategy for Mass Antimalarial Drug Administration in Cambodia. Am J Trop Med Hyg 2018; 98:100-104. [PMID: 29165227 PMCID: PMC5928715 DOI: 10.4269/ajtmh.17-0428] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mass drug administration (MDA) to interrupt malaria transmission requires the participation of entire communities. As part of a clinical trial in western Cambodia, four villages received MDA in 2015–2016. Before approaching study communities, a collaboration was established with the local health authorities, village leaders, and village malaria workers. Formative research guided the development of engagement strategies. In each village, a team of volunteers was formed to explain MDA to their neighbors and provide support during implementation. Public mobilization events featuring drama and music were used to introduce MDA. Villages comprised groups with different levels of understanding and interests; therefore, multiple tailored engagement strategies were required. The main challenges were explaining malaria transmission, managing perceptions of drug side effects, and reaching mobile populations. It was important that local leaders took a central role in community engagement. Coverage during each round of MDA averaged 84%, which met the target for the trial.
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Affiliation(s)
- Thomas J Peto
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rupam Tripura
- Department of Infectious Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chan Davoeung
- Department of Provincial Health, Battambang, Cambodia
| | - Chea Nguon
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Sanann Nou
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chhouen Heng
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pich Kunthea
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Bipin Adhikari
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Renly Lim
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
| | - Nicola James
- Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher Pell
- Centre for Social Science and Global Health, University of Amsterdam, The Netherlands.,Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
| | - Phaik Yeong Cheah
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,The Ethox Centre, University of Oxford, Oxford, United Kingdom
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76
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Landier J, Rebaudet S, Piarroux R, Gaudart J. Spatiotemporal analysis of malaria for new sustainable control strategies. BMC Med 2018; 16:226. [PMID: 30509258 PMCID: PMC6278049 DOI: 10.1186/s12916-018-1224-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 11/20/2018] [Indexed: 12/31/2022] Open
Abstract
Malaria transmission is highly heterogeneous through time and space, and mapping of this heterogeneity is necessary to better understand local dynamics. New targeted policies are needed as numerous countries have placed malaria elimination on their public health agenda for 2030. In this context, developing national health information systems and collecting information at sufficiently precise scales (at least at the 'week' and 'village' scales), is of strategic importance. In a recent study, Macharia et al. relied on extensive prevalence survey data to develop malaria risk maps for Kenya, including uncertainty assessments specifically designed to support decision-making by the National Malaria Control Program. Targeting local persistent transmission or epidemiologic changes is necessary to maintain efficient control, but also to deploy sustainable elimination strategies against identified transmission bottlenecks such as the reservoir of subpatent infections. Such decision-making tools are paramount to allocate resources based on sound scientific evidence and public health priorities.Please see related article: https://malariajournal.biomedcentral.com/articles/10.1186/s12936-018-2489-9 .
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Affiliation(s)
- Jordi Landier
- Aix Marseille Univ, INSERM, IRD, SESSTIM, Sciences Economiques & Sociales de la Santé & Traitement de l'Information Médicale, Marseille, France
| | - Stanislas Rebaudet
- APHM, Assistance Publique - Hôpitaux de Marseille, Marseille, France.,Hôpital Européen, Marseille, France
| | - Renaud Piarroux
- Sorbonne Université, INSERM, Institut Pierre-Louis d'Epidémiologie et de Santé Publique, AP-HP, Hôpital Pitié-Salpêtrière, Paris, France
| | - Jean Gaudart
- Aix Marseille Univ, APHM, INSERM, IRD, SESSTIM, Hop Timone, BioSTIC, Biostatistic & ICT, Marseille, France.
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77
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Thway AM, Rotejanaprasert C, Sattabongkot J, Lawawirojwong S, Thi A, Hlaing TM, Soe TM, Kaewkungwal J. Bayesian spatiotemporal analysis of malaria infection along an international border: Hlaingbwe Township in Myanmar and Tha-Song-Yang District in Thailand. Malar J 2018; 17:428. [PMID: 30445962 PMCID: PMC6240260 DOI: 10.1186/s12936-018-2574-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/09/2018] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND One challenge in moving towards malaria elimination is cross-border malaria infection. The implemented measures to prevent and control malaria re-introduction across the demarcation line between two countries require intensive analyses and interpretation of data from both sides, particularly in border areas, to make correct and timely decisions. Reliable maps of projected malaria distribution can help to direct intervention strategies. In this study, a Bayesian spatiotemporal analytic model was proposed for analysing and generating aggregated malaria risk maps based on the exceedance probability of malaria infection in the township-district adjacent to the border between Myanmar and Thailand. Data of individual malaria cases in Hlaingbwe Township and Tha-Song-Yang District during 2016 were extracted from routine malaria surveillance databases. Bayesian zero-inflated Poisson model was developed to identify spatial and temporal distributions and associations between malaria infections and risk factors. Maps of the descriptive statistics and posterior distribution of predicted malaria infections were also developed. RESULTS A similar seasonal pattern of malaria was observed in both Hlaingbwe Township and Tha-Song-Yang District during the rainy season. The analytic model indicated more cases of malaria among males and individuals aged ≥ 15 years. Mapping of aggregated risk revealed consistently high or low probabilities of malaria infection in certain village tracts or villages in interior parts of each country, with higher probability in village tracts/villages adjacent to the border in places where it could easily be crossed; some border locations with high mountains or dense forests appeared to have fewer malaria cases. The probability of becoming a hotspot cluster varied among village tracts/villages over the year, and some had close to no cases all year. CONCLUSIONS The analytic model developed in this study could be used for assessing the probability of hotspot cluster, which would be beneficial for setting priorities and timely preventive actions in such hotspot cluster areas. This approach might help to accelerate reaching the common goal of malaria elimination in the two countries.
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Affiliation(s)
- Aung Minn Thway
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chawarat Rotejanaprasert
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Siam Lawawirojwong
- Geo-Informatics and Space Technology Development Agency, Bangkok, Thailand
| | - Aung Thi
- National Malaria Control Program, Nay Pyi Taw, Myanmar
| | | | | | - Jaranit Kaewkungwal
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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78
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Nascimento J, Sampaio VS, Karl S, Kuehn A, Almeida A, Vitor-Silva S, de Melo GC, Baia da Silva DC, C. P. Lopes S, Fé NF, Lima JBP, Guerra MGB, Pimenta PFP, Bassat Q, Mueller I, Lacerda MVG, Monteiro WM. Use of anthropophilic culicid-based xenosurveillance as a proxy for Plasmodium vivax malaria burden and transmission hotspots identification. PLoS Negl Trop Dis 2018; 12:e0006909. [PMID: 30418971 PMCID: PMC6258424 DOI: 10.1371/journal.pntd.0006909] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 11/26/2018] [Accepted: 10/08/2018] [Indexed: 12/14/2022] Open
Abstract
Vector-borne diseases account for more than 17% of all infectious diseases, causing more than one million deaths annually. Malaria remains one of the most important public health problems worldwide. These vectors are bloodsucking insects, which can transmit disease-producing microorganisms during a blood meal. The contact of culicids with human populations living in malaria-endemic areas suggests that the identification of Plasmodium genetic material in the blood present in the gut of these mosquitoes may be possible. The process of assessing the blood meal for the presence of pathogens is termed 'xenosurveillance'. In view of this, the present work investigated the relationship between the frequency with which Plasmodium DNA is found in culicids and the frequency with which individuals are found to be carrying malaria parasites. A cross-sectional study was performed in a peri-urban area of Manaus, in the Western Brazilian Amazon, by simultaneously collecting human blood samples and trapping culicids from households. A total of 875 individuals were included in the study and a total of 13,374mosquito specimens were captured. Malaria prevalence in the study area was 7.7%. The frequency of households with at least one culicid specimen carrying Plasmodium DNA was 6.4%. Plasmodium infection incidence was significantly related to whether any Plasmodium positive blood-fed culicid was found in the same household [IRR 3.49 (CI95% 1.38-8.84); p = 0.008] and for indoor-collected culicids [IRR 4.07 (CI95%1.25-13.24); p = 0.020]. Furthermore, the number of infected people in the house at the time of mosquito collection was related to whether there were any positive blood-fed culicid mosquitoes in that household for collection methods combined [IRR 4.48 (CI95%2.22-9.05); p<0.001] or only for indoor-collected culicids [IRR 4.88 (CI95%2.01-11.82); p<0.001]. Our results suggest that xenosurveillance can be used in endemic tropical regions in order to estimate the malaria burden and identify transmission foci in areas where Plasmodium vivax is predominant.
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Affiliation(s)
- Joabi Nascimento
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
- Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, AM, Brazil
| | - Vanderson S. Sampaio
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
- Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, AM, Brazil
| | - Stephan Karl
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Entomology Section, Vector-borne Diseases Unit, Papua New Guinea Institute of Medical Research, Papua, New Guinea
- Department of Medical Biology, University of Melbourne, Australia
| | - Andrea Kuehn
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
| | - Anne Almeida
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
- Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, AM, Brazil
| | - Sheila Vitor-Silva
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
- Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, AM, Brazil
| | - Gisely Cardoso de Melo
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
- Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, AM, Brazil
| | - Djane C. Baia da Silva
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
| | | | - Nelson F. Fé
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
| | - José B. Pereira Lima
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil
| | - Maria G. Barbosa Guerra
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
- Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, AM, Brazil
| | - Paulo F. P. Pimenta
- Laboratório de Entomologia Médica, Centro de Pesquisas René Rachou (Fiocruz), Belo Horizonte, MG, Brazil
| | - Quique Bassat
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- ICREA, Barcelona, Spain
- Pediatric Infectious Diseases Unit, Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, Spain
| | - Ivo Mueller
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Australia
- Parasites & Hosts Unit, Institut Pasteur, Paris, France
| | - Marcus V. G. Lacerda
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
- Instituto Leônidas & Maria Deane, Fundação Oswaldo Cruz, Manaus, AM, Brazil
| | - Wuelton M. Monteiro
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brazil
- Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, AM, Brazil
- * E-mail:
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79
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Abstract
Malaria is a major cause of anaemia in tropical areas. Malaria infection causes haemolysis of infected and uninfected erythrocytes and bone marrow dyserythropoiesis which compromises rapid recovery from anaemia. In areas of high malaria transmission malaria nearly all infants and young children, and many older children and adults have a reduced haemoglobin concentration as a result. In these areas severe life-threatening malarial anaemia requiring blood transfusion in young children is a major cause of hospital admission, particularly during the rainy season months when malaria transmission is highest. In severe malaria, the mortality rises steeply below an admission haemoglobin of 3 g/dL, but it also increases with higher haemoglobin concentrations approaching the normal range. In the management of severe malaria transfusion thresholds remain uncertain. Prevention of malaria by vector control, deployment of insecticide-treated bed nets, prompt and accurate diagnosis of illness and appropriate use of effective anti-malarial drugs substantially reduces the burden of anaemia in tropical countries.
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Affiliation(s)
- Nicholas J White
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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80
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Gilder ME, Hanpithakphong W, Hoglund RM, Tarning J, Win HH, Hilda N, Chu CS, Bancone G, Carrara VI, Singhasivanon P, White NJ, Nosten F, McGready R. Primaquine Pharmacokinetics in Lactating Women and Breastfed Infant Exposures. Clin Infect Dis 2018; 67:1000-1007. [PMID: 29590311 PMCID: PMC6137118 DOI: 10.1093/cid/ciy235] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/21/2018] [Indexed: 02/04/2023] Open
Abstract
Background Primaquine is the only drug providing radical cure of Plasmodium vivax malaria. It is not recommended for breastfeeding women as it causes hemolysis in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals, and breast milk excretion and thus infant exposure are not known. Methods Healthy G6PD-normal breastfeeding women with previous P. vivax infection and their healthy G6PD-normal infants between 28 days and 2 years old were enrolled. Mothers took primaquine 0.5 mg/kg/day for 14 days. Primaquine and carboxyprimaquine concentrations were measured in maternal venous plasma, capillary plasma, and breast milk samples and infant capillary plasma samples taken on days 0, 3, 7, and 13. Results In 20 mother-infant pairs, primaquine concentrations were below measurement thresholds in all but 1 infant capillary plasma sample (that contained primaquine 2.6 ng/mL), and carboxyprimaquine was likewise unmeasurable in the majority of infant samples (maximum value 25.8 ng/mL). The estimated primaquine dose received by infants, based on measured breast milk levels, was 2.98 µg/kg/day (ie, ~0.6% of a hypothetical infant daily dose of 0.5 mg/kg). There was no evidence of drug-related hemolysis in the infants. Maternal levels were comparable to levels in nonlactating patients, and adverse events in mothers were mild. Conclusions The concentrations of primaquine in breast milk are very low and therefore very unlikely to cause adverse effects in the breastfeeding infant. Primaquine should not be withheld from mothers breastfeeding infants or young children. More information is needed in neonates. Clinical Trials Registration NCT01780753.
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Affiliation(s)
- Mary Ellen Gilder
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot
| | - Warunee Hanpithakphong
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Richard M Hoglund
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Joel Tarning
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Htun Htun Win
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot
| | - Naw Hilda
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot
| | - Cindy S Chu
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Germana Bancone
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Verena I Carrara
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot
| | - Pratap Singhasivanon
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - François Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Rose McGready
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
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81
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Sattabongkot J, Suansomjit C, Nguitragool W, Sirichaisinthop J, Warit S, Tiensuwan M, Buates S. Prevalence of asymptomatic Plasmodium infections with sub-microscopic parasite densities in the northwestern border of Thailand: a potential threat to malaria elimination. Malar J 2018; 17:329. [PMID: 30208895 PMCID: PMC6134695 DOI: 10.1186/s12936-018-2476-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/04/2018] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Asymptomatic infections with sub-microscopic Plasmodium serve as a silent reservoir of disease, critical to sustaining a low level of remanent malaria in the population. These infections must be effectively identified and targeted for elimination. The sensitivity of light microscopy, the traditional method used for diagnosing Plasmodium infections, is frequently insufficient for detecting asymptomatic infections due to the low density of parasitaemia. The objective of this study was to explore the current prevalence of asymptomatic sub-microscopic Plasmodium carriages to evaluate the parasite reservoir amongst residents from 7 hamlets in Tak Province in northwestern Thailand using a highly sensitive molecular method. METHODS Malaria infection was screened in a real-world setting from 3650 finger-prick blood specimens collected in a mass cross-sectional survey using light microscopy and loop-mediated isothermal amplification (LAMP). LAMP results were later confirmed in a laboratory setting in Bangkok using nested PCR, restriction enzyme digestion and DNA sequencing. The association of malaria infection with demographic factors was explored. RESULTS Parasite prevalence was 0.27% (10/3650) as determined by microscopy. Sub-microscopic infection prevalence was 2.33% (85/3650) by LAMP. Of these, 30.6% (26/85) were infected with Plasmodium falciparum, 52.9% (45/85) with Plasmodium vivax, 2.4% (2/85) with Plasmodium malariae, 4.7% (4/85) with mixed P. falciparum and P. vivax, and 9.4% (8/85) had parasite densities too low for species identification. Asymptomatic carriages (T < 37.5 °C) accounted for 95% (76/80) of all sub-microscopic cases with the highest prevalence occurring in the subjects 31-45 years of age (p ≤ 0.035). Participants working on plantations or as merchants had an increased infection risk. Evaluation by microscopy identified 10.53% (10/95) of all Plasmodium infected participants. CONCLUSION Participants carrying asymptomatic Plasmodium infections with sub-microscopic parasite densities are considerable in this area. These findings provide the true disease burden and risk factors in this region. This information helps to direct policy makers towards better schemes and delivery of targeted interventions. Moreover, this is the first study to use LAMP in mass screening for sub-clinical and sub-microscopic infections in a field setting in Thailand. LAMP proves to be a sensitive and field-deployable assay suitable for national malaria control screening campaigns.
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Affiliation(s)
- Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chayanut Suansomjit
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Wang Nguitragool
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Saradee Warit
- Tuberculosis Research Laboratory, Medical Molecular Biology Research Unit, BIOTEC, National Science and Technology Development Agency, Thailand Science Park, Pathum Thani, Thailand
| | - Montip Tiensuwan
- Department of Mathematics, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Sureemas Buates
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand.
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82
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Agnihotri N, Agnihotri A. Clinical Malaria as a Rare post Blood Donation Complication. Indian J Hematol Blood Transfus 2018; 34:589-590. [PMID: 30127586 DOI: 10.1007/s12288-017-0900-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 10/30/2017] [Indexed: 10/18/2022] Open
Affiliation(s)
- Naveen Agnihotri
- Department of Blood Transfusion Medicine, Nayati Medicity, NH-2, Mathura, Uttar Pradesh 283001 India
| | - Ajju Agnihotri
- Department of Blood Transfusion Medicine, Nayati Medicity, NH-2, Mathura, Uttar Pradesh 283001 India
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83
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84
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Zhao Y, Zeng J, Zhao Y, Liu Q, He Y, Zhang J, Yang Z, Fan Q, Wang Q, Cui L, Cao Y. Risk factors for asymptomatic malaria infections from seasonal cross-sectional surveys along the China-Myanmar border. Malar J 2018; 17:247. [PMID: 29973194 PMCID: PMC6032786 DOI: 10.1186/s12936-018-2398-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/22/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Border malaria, a shared phenomenon in the Greater Mekong Sub-region of Southeast Asia, is a major obstacle for regional malaria elimination. Along the China-Myanmar border, an additional problem arose as a result of the settlement of internally displaced people (IDP) in the border region. Since asymptomatic malaria significantly impacts transmission dynamics, assessment of the prevalence, dynamics and risk factors of asymptomatic malaria infections is necessary. METHODS Cross-sectional surveys were carried out in 3 seasons (March and April, July and November) and 2 sites (villages and IDP camps) in 2015. A total of 1680 finger-prick blood samples were collected and used for parasite detection by microscopy and nested RT-PCR (nRT-PCR). Logistic regression models were used to explore the risk factors associated with asymptomatic malaria at individual and household levels. RESULTS The prevalence of asymptomatic Plasmodium infections was 23.3% by nRT-PCR, significantly higher than that detected by microscopy (1.5%). The proportions of Plasmodium vivax, Plasmodium falciparum and mixed-species infections were 89.6, 8.1 and 2.3%, respectively. Asymptomatic infections showed obvious seasonality with higher prevalence in the rainy season. Logistic regression analysis identified males and school children (≤ 15 years) as the high-risk populations. Vector-based interventions, including bed net and indoor residual spray, were found to have significant impacts on asymptomatic Plasmodium infections, with non-users of these measures carrying much higher risks of infection. In addition, individuals living in poorly constructed households or farther away from clinics were more prone to asymptomatic infections. CONCLUSIONS Sub-microscopic Plasmodium infections were highly prevalent in the border human populations from IDP camps and surrounding villages. Both individual- and household-level risk factors were identified, which provides useful information for identifying the high-priority populations to implement targeted malaria control.
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Affiliation(s)
- Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Jie Zeng
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Yonghong Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Qingyang Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Yang He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Jiaqi Zhang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Qinghui Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China.
| | - Liwang Cui
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China. .,Department of Entomology, Pennsylvania State University, University Park, State College, PA, 16802, USA.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China.
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85
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Goldlust SM, Thuan PD, Giang DDH, Thang ND, Thwaites GE, Farrar J, Thanh NV, Nguyen TD, Grenfell BT, Boni MF, Hien TT. The decline of malaria in Vietnam, 1991-2014. Malar J 2018; 17:226. [PMID: 29880051 PMCID: PMC5992833 DOI: 10.1186/s12936-018-2372-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 05/28/2018] [Indexed: 02/04/2023] Open
Abstract
Background Despite the well-documented clinical efficacy of artemisinin-based combination therapy (ACT) against malaria, the population-level effects of ACT have not been studied thoroughly until recently. An ideal case study for these population-level effects can be found in Vietnam’s gradual adoption of artemisinin in the 1990s. Methods and results Analysis of Vietnam’s national annual malaria reports (1991–2014) revealed that a 10% increase in artemisinin procurement corresponded to a 32.8% (95% CI 27.7–37.5%) decline in estimated malaria cases. There was no consistent national or regional effect of vector control on malaria. The association between urbanization and malaria was generally negative and sometimes statistically significant. Conclusions The decline of malaria in Vietnam can largely be attributed to the adoption of artemisinin-based case management. Recent analyses from Africa showed that insecticide-treated nets had the greatest effect on lowering malaria prevalence, suggesting that the success of interventions is region-specific. Continuing malaria elimination efforts should focus on both vector control and increased access to ACT. Electronic supplementary material The online version of this article (10.1186/s12936-018-2372-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sandra M Goldlust
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,Department of Biology, Georgetown University, Washington, DC, USA.,Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Phung Duc Thuan
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Dang Duy Hoang Giang
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Ngo Duc Thang
- National Institutes for Malariology, Parasitology, and Entomology, Hanoi, Vietnam
| | - Guy E Thwaites
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Jeremy Farrar
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,The Wellcome Trust, London, UK
| | - Ngo Viet Thanh
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Tran Dang Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Bryan T Grenfell
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Maciej F Boni
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK. .,Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA, USA.
| | - Tran Tinh Hien
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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86
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Ya-Umphan P, Cerqueira D, Cottrell G, Parker DM, Fowkes FJI, Nosten F, Corbel V. Anopheles Salivary Biomarker as a Proxy for Estimating Plasmodium falciparum Malaria Exposure on the Thailand-Myanmar Border. Am J Trop Med Hyg 2018; 99:350-356. [PMID: 29869601 DOI: 10.4269/ajtmh.18-0081] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Timely identification and treatment of malaria transmission "hot spots" is essential to achieve malaria elimination. Here we investigate the relevance of using an Anopheles salivary biomarker to estimate Plasmodium falciparum malaria exposure risk along the Thailand-Myanmar border to guide malaria control. Between May 2013 and December 2014, > 9,000 blood samples collected in a cluster randomized control trial were screened with serological assays to measure the antibody responses to Anopheles salivary antigen (gSG6-P1) and P. falciparum malaria antigens (circumsporozoite protein, merozoite surface protein 119 [MSP-119]). Plasmodium falciparum infections were monitored through passive and active case detection. Seroprevalence to gSG6-P1, MSP-119, and CSP were 71.8% (95% Confidence interval [CI]: 70.9, 72.7), 68.6% (95% CI: 67.7, 69.5), and 8.6% (95% CI: 8.0, 9.2), respectively. Multivariate analysis showed that individuals with the highest Ab response to gSG6-P1 had six times the odds of being positive to CSP antigens (P < 0.001) and two times the odds of P. falciparum infection compared with low gSG6-P1 responders (P = 0.004). Spatial scan statistics revealed the presence of clusters of gSG6-P1 that partially overlapped P. falciparum infections. The gSG6-P1 salivary biomarker represents a good proxy for estimating P. falciparum malaria risk and could serve to implement hot spot-targeted vector control interventions to achieve malaria elimination.
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Affiliation(s)
- Phubeth Ya-Umphan
- Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (IRD 224-CNRS 5290 UM1-UM2), Institut de Recherche pour le Développement (IRD), University of Montpellier, Montpellier, France
| | - Dominique Cerqueira
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Gilles Cottrell
- Institut de Recherche pour le Développement (IRD), Université Paris Descartes, Sorbonne Paris Cité, UMR 216, Paris, France
| | - Daniel M Parker
- Department of Population Health and Disease Prevention, University of California, Irvine, California.,Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Freya J I Fowkes
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia.,Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.,Disease Elimination Program, Life Sciences, Burnet Institute, Melbourne, Australia
| | - Francois Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, United Kingdom.,Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Vincent Corbel
- Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (IRD 224-CNRS 5290 UM1-UM2), Institut de Recherche pour le Développement (IRD), University of Montpellier, Montpellier, France
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87
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Goomber S, Mishra N, Anvikar A, Yadav CP, Valecha N. Spatio-temporal distribution of PfMDR1 polymorphism among uncomplicated Plasmodium falciparum malaria cases along international border of north east India. INFECTION GENETICS AND EVOLUTION 2018; 63:285-290. [PMID: 29842979 DOI: 10.1016/j.meegid.2018.05.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/22/2018] [Accepted: 05/25/2018] [Indexed: 10/16/2022]
Abstract
PfMDR1 single nucleotide polymorphisms (SNP) are good correlate markers for antimalarial drug resistance worldwide. Present study is a comprehensive view of screening of PfMDR1 polymorphism to antimalarials practiced with geography and time. Study sites Mizoram, Tripura, Meghalaya chosen are at multivariate drug pressure due to cross border migration and transmission. Mizoram is gateway to south east Asia through Myanmar whereas Tripura, Meghalaya share porous border with Bangladesh. Baseline finger pricked blood stained filter paper for confirmed uncomplicated Plasmodium falciparum infected patients (year 2015) were obtained from National Institute of Malaria Research, New Delhi, India. PfMDR1 polymorphism for codon N86Y, Y184F, D1246Y was determined by PCR-RFLP, further confirmed by sequencing. There observed marked predominance of Plasmodium isolates with PfMDR1 wild type alleles for all codons under study i.e. 86, 184, 1246. Spatially, Plasmodium isolates from Mizoram were most diverse with co-existence of PfMDR1 genotype with NYD, YYD, NFD haplotypes, followed by Tripura. Isolates from Meghalaya were of all NYD haplotype. Reports, referring to screening of PfMDR1 SNPs to CQ/SP/AS-SP across India, were archived. Temporal study show distinct rise in proportion of PfMDR1 wild type N86 allele since introduction of Artemether-Lumefantrine as first line antimalarial. Hence spatio-temporal screening of Plasmodium population with PfMDR1 single nucleotide polymorphism accounts for its association with antimalarial susceptibility and validate PfMDR1 SNPs as antimalarial drug resistant marker.
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Affiliation(s)
- Shelly Goomber
- National Institute of Malaria Research, Indian Council of Medical Research, Sector - 8, Dwarka, New Delhi, India.
| | - Neelima Mishra
- National Institute of Malaria Research, Indian Council of Medical Research, Sector - 8, Dwarka, New Delhi, India
| | - Anup Anvikar
- National Institute of Malaria Research, Indian Council of Medical Research, Sector - 8, Dwarka, New Delhi, India
| | - Chander Prakash Yadav
- National Institute of Malaria Research, Indian Council of Medical Research, Sector - 8, Dwarka, New Delhi, India
| | - Neena Valecha
- National Institute of Malaria Research, Indian Council of Medical Research, Sector - 8, Dwarka, New Delhi, India
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88
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Flanagan KL, Fink AL, Plebanski M, Klein SL. Sex and Gender Differences in the Outcomes of Vaccination over the Life Course. Annu Rev Cell Dev Biol 2018; 33:577-599. [PMID: 28992436 DOI: 10.1146/annurev-cellbio-100616-060718] [Citation(s) in RCA: 313] [Impact Index Per Article: 52.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Both sex (i.e., biological differences) and gender (i.e., social or cultural influences) impact vaccine acceptance, responses, and outcomes. Clinical data illustrate that among children, young adults, and aged individuals, males and females differ in vaccine-induced immune responses, adverse events, and protection. Although males are more likely to receive vaccines, following vaccination, females typically develop higher antibody responses and report more adverse effects of vaccination than do males. Human, nonhuman animal, and in vitro studies reveal numerous immunological, genetic, hormonal, and environmental factors that differ between males and females and contribute to sex- and gender-specific vaccine responses and outcomes. Herein, we address the impact of sex and gender variables that should be considered in preclinical and clinical studies of vaccines.
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Affiliation(s)
- Katie L Flanagan
- Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia, 3800; ,
| | - Ashley L Fink
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205; ,
| | - Magdalena Plebanski
- Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia, 3800; ,
| | - Sabra L Klein
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205; ,
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89
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Landier J, Parker DM, Thu AM, Lwin KM, Delmas G, Nosten FH. Effect of generalised access to early diagnosis and treatment and targeted mass drug administration on Plasmodium falciparum malaria in Eastern Myanmar: an observational study of a regional elimination programme. Lancet 2018; 391:1916-1926. [PMID: 29703425 PMCID: PMC5946089 DOI: 10.1016/s0140-6736(18)30792-x] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 12/31/2022]
Abstract
BACKGROUND Potentially untreatable Plasmodium falciparum malaria threatens the Greater Mekong subregion. A previous series of pilot projects in Myanmar, Laos, Cambodia, and Vietnam suggested that mass drug administration was safe, and when added to provision of early diagnosis and treatment, could reduce the reservoir of P falciparum and interrupts transmission. We examined the effects of a scaled-up programme of this strategy in four townships of eastern Myanmar on the incidence of P falciparum malaria. METHODS The programme was implemented in the four townships of Myawaddy, Kawkareik, Hlaingbwe, and Hpapun in Kayin state, Myanmar. Increased access to early diagnosis and treatment of malaria was provided to all villages through community-based malaria posts equipped with rapid diagnostic tests, and treatment with artemether-lumefantrine plus single low-dose primaquine. Villages were identified as malarial hotspots (operationally defined as >40% malaria, of which 20% was P falciparum) with surveys using ultrasensitive quantitative PCR either randomly or targeted at villages where the incidence of clinical cases of P falciparum malaria remained high (ie, >100 cases per 1000 individuals per year) despite a functioning malaria post. During each survey, a 2 mL sample of venous blood was obtained from randomly selected adults. Hotspots received targeted mass drug administration with dihydroartemisinin-piperaquine plus single-dose primaquine once per month for 3 consecutive months in addition to the malaria posts. The main outcome was the change in village incidence of clinical P falciparum malaria, quantified using a multivariate, generalised, additive multilevel model. Malaria prevalence was measured in the hotspots 12 months after mass drug administration. FINDINGS Between May 1, 2014, and April 30, 2017, 1222 malarial posts were opened, providing early diagnosis and treatment to an estimated 365 000 individuals. Incidence of P falciparum malaria decreased by 60 to 98% in the four townships. 272 prevalence surveys were undertaken and 69 hotspot villages were identified. By April 2017, 50 hotspots were treated with mass drug administration. Hotspot villages had a three times higher incidence of P falciparum at malarial posts than neighbouring villages (adjusted incidence rate ratio [IRR] 2·7, 95% CI 1·8-4·4). Early diagnosis and treatment was associated with a significant decrease in P falciparum incidence in hotspots (IRR 0·82, 95% CI 0·76-0·88 per quarter) and in other villages (0·75, 0·73-0·78 per quarter). Mass drug administration was associated with a five-times decrease in P falciparum incidence within hotspot villages (IRR 0·19, 95% CI 0·13-0·26). By April, 2017, 965 villages (79%) of 1222 corresponding to 104 village tracts were free from P falciparum malaria for at least 6 months. The prevalence of wild-type genotype for K13 molecular markers of artemisinin resistance was stable over the three years (39%; 249/631). INTERPRETATION Providing early diagnosis and effective treatment substantially decreased village-level incidence of artemisinin-resistant P falciparum malaria in hard-to-reach, politically sensitive regions of eastern Myanmar. Targeted mass drug administration significantly reduced malaria incidence in hotspots. If these activities could proceed in all contiguous endemic areas in addition to standard control programmes already implemented, there is a possibility of subnational elimination of P falciparum. FUNDING The Bill & Melinda Gates Foundation, the Regional Artemisinin Initiative (Global Fund against AIDS, Tuberculosis and Malaria), and the Wellcome Trust.
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Affiliation(s)
- Jordi Landier
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; Institut de Recherches pour le Développement, Aix Marseille Univ, INSERM, SESSTIM, Sciences Economiques & Sociales de la Santé & Traitement de l'Information Médicale, Marseille, France.
| | - Daniel M Parker
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; Department of Population Health and Disease Prevention, University of California, Irvine, CA, USA
| | - Aung Myint Thu
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Khin Maung Lwin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Gilles Delmas
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - François H Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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90
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Nguyen TN, von Seidlein L, Nguyen TV, Truong PN, Hung SD, Pham HT, Nguyen TU, Le TD, Dao VH, Mukaka M, Day NP, White NJ, Dondorp AM, Thwaites GE, Hien TT. The persistence and oscillations of submicroscopic Plasmodium falciparum and Plasmodium vivax infections over time in Vietnam: an open cohort study. THE LANCET. INFECTIOUS DISEASES 2018; 18:565-572. [PMID: 29398388 PMCID: PMC5910058 DOI: 10.1016/s1473-3099(18)30046-x] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/29/2017] [Accepted: 11/20/2017] [Indexed: 11/27/2022]
Abstract
BACKGROUND A substantial proportion of Plasmodium species infections are asymptomatic with densities too low to be detectable with standard diagnostic techniques. The importance of such asymptomatic plasmodium infections in malaria transmission is probably related to their duration and density. To explore the duration of asymptomatic plasmodium infections and changes in parasite densities over time, a cohort of participants who were infected with Plasmodium parasites was observed over a 2-year follow-up period. METHODS In this open cohort study, inhabitants of four villages in Vietnam were invited to participate in baseline and subsequent 3-monthly surveys up to 24 months, which included the collection of venous blood samples. Samples were batch-screened using ultra-sensitive (u)PCR (lower limit of detection of 22 parasites per mL). Participants found to be infected by uPCR during any of these surveys were invited to join a prospective cohort and provide monthly blood samples. We estimated the persistence of Plasmodium falciparum and Plasmodium vivax infections and changes in parasite densities over a study period of 24 months. FINDINGS Between Dec 1, 2013, and Jan 8, 2016, 356 villagers participated in between one and 22 surveys. These study participants underwent 4248 uPCR evaluations (11·9 tests per participant). 1874 (32%) of 4248 uPCR tests indicated a plasmodium infection; 679 (36%) of 1874 tests were P falciparum monoinfections, 507 (27%) were P vivax monoinfections, 463 (25%) were co-infections with P falciparum and P vivax, and 225 (12%) were indeterminate species of Plasmodium. The median duration of P falciparum infection was 2 months (IQR 1-3); after accounting for censoring, participants had a 20% chance of having parasitaemia for 4 months or longer. The median duration of P vivax infection was 6 months (3-9), and participants had a 59% chance of having parasitaemia for 4 months or longer. The parasite densities of persistent infections oscillated; following ultralow-density infections, high-density infections developed frequently. INTERPRETATION Persistent largely asymptomatic P vivax and P falciparum infections are common in this area of low seasonal malaria transmission. Infections with low-density parasitaemias can develop into much higher density infections at a later time, which are likely to sustain malaria endemicity. FUNDING The Wellcome Trust, Bill & Melinda Gates Foundation.
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Affiliation(s)
- Thuy-Nhien Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Oversea Programme, Ho Chi Minh City, Vietnam
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK.
| | - Tuong-Vy Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Oversea Programme, Ho Chi Minh City, Vietnam
| | - Phuc-Nhi Truong
- Oxford University Clinical Research Unit, Wellcome Trust Major Oversea Programme, Ho Chi Minh City, Vietnam
| | - Son Do Hung
- Oxford University Clinical Research Unit, Wellcome Trust Major Oversea Programme, Ho Chi Minh City, Vietnam
| | - Huong-Thu Pham
- Oxford University Clinical Research Unit, Wellcome Trust Major Oversea Programme, Ho Chi Minh City, Vietnam
| | - Tam-Uyen Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Oversea Programme, Ho Chi Minh City, Vietnam
| | - Thanh Dong Le
- Institute of Malariology, Parasitology, and Entomology (IMPE), Ho Chi Minh City, Vietnam
| | - Van Hue Dao
- Center for Malariology, Parasitology and Entomology Control, Ninh Thuan Province, Vietnam
| | - Mavuto Mukaka
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Nicholas Pj Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Guy E Thwaites
- Oxford University Clinical Research Unit, Wellcome Trust Major Oversea Programme, Ho Chi Minh City, Vietnam; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Tran Tinh Hien
- Oxford University Clinical Research Unit, Wellcome Trust Major Oversea Programme, Ho Chi Minh City, Vietnam; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
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91
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Micro-epidemiology of malaria in an elimination setting in Central Vietnam. Malar J 2018; 17:119. [PMID: 29554901 PMCID: PMC5859719 DOI: 10.1186/s12936-018-2262-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/08/2018] [Indexed: 11/10/2022] Open
Abstract
Background In Vietnam, malaria persists in remote forested regions where infections are spatially heterogeneous, mostly asymptomatic and with low parasite density. Previous studies in Vietnam have investigated broad behavioural concepts such as ‘engaging in forest activities’ as risk factors for malaria infection, which may not explain heterogeneity in malaria risk, especially in malaria elimination settings. Methods A mixed methods study combining ethnographic research and a cross-sectional survey was embedded in a 1-year malariometric cohort study in three ethnic minority villages in South Tra My district, Quang Nam Province in Central Vietnam. Qualitative data collection included in-depth interviews, informal conversations and participant observations over a 2-month period, and the findings were used to develop the questionnaire used in the cross-sectional survey. The latter collected data on evening activities, mobility patterns and household characteristics. The primary outcome, recent exposure to malaria, was defined using the classification and regression tree method to determine significant changes in antibody titres during the year preceding the survey. Risk factor analyses for recent exposure to malaria were conducted using logistic regression. Results 22 in-depth interviews and numerous participant observations were recorded during the ethnographic research (April to June 2015), and 160 adults (86% response rate) responded to the cross-sectional survey (November to December 2015). Recent exposure to Plasmodium falciparum malaria was estimated at 22.9 and at 17.1% for Plasmodium vivax. Ongoing malaria transmission appears to be maintained by activities that delay or disrupt sleeping in a permanent structure in which a bed net could be hung, including evening drinking gatherings, fishing, logging in the forest and outdoor TV watching. Conclusions Vector control tools for outdoor evening activities in villages as well as at farms, forest and river locations should be incorporated into current malaria elimination efforts in Central Vietnam. Micro-epidemiology studies using mixed-methods designs can provide a comprehensive understanding of the malaria risk at fine spatial scales and better inform the implementation of targeted interventions for malaria elimination. Electronic supplementary material The online version of this article (10.1186/s12936-018-2262-0) contains supplementary material, which is available to authorized users.
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92
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Katrak S, Nayebare P, Rek J, Arinaitwe E, Nankabirwa JI, Kamya M, Dorsey G, Rosenthal PJ, Greenhouse B. Clinical consequences of submicroscopic malaria parasitaemia in Uganda. Malar J 2018; 17:67. [PMID: 29402282 PMCID: PMC5800031 DOI: 10.1186/s12936-018-2221-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 01/31/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Submicroscopic malaria parasitaemia is common in both high- and low-endemicity settings, but its clinical consequences are unclear. METHODS A cohort of 364 children (0.5-10 years of age) and 106 adults was followed from 2011 to 2016 in Tororo District, Uganda using passive surveillance for malaria episodes and active surveillance for parasitaemia. Participants presented every 90 days for routine visits (n = 9075); a subset was followed every 30 days. Participants who presented with fever and a positive blood smear were treated for malaria. At all routine visits microscopy was performed and samples from subjects with a negative blood smear underwent loop-mediated isothermal amplification for detection of plasmodial DNA. RESULTS Submicroscopic parasitaemia was common; the proportion of visits with submicroscopic parasitemia was 25.8% in children and 39.2% in adults. For children 0.5-10 years of age, but not adults, having microscopic and submicroscopic parasitaemia at routine visits was significantly associated with both fever (adjusted risk ratios [95% CI], 2.64 [2.16-3.22], 1.67 [1.37-2.03]) and non-febrile illness (aRR [CI], 1.52 [1.30-1.78], 1.26 [1.09-1.47]), compared to not having parasitaemia. After stratifying by age, significant associations were seen between submicroscopic parasitaemia and fever in children aged 2-< 5 and 5-10 years (aRR [CI], 1.42 [1.03-1.98], 2.01 [1.49-2.71]), and submicroscopic parasitaemia and non-febrile illness in children aged 5-10 years (aRR [CI], 1.44 [1.17-1.78]). These associations were maintained after excluding individuals with a malaria episode within the preceding 14 or following 7 days, and after adjusting for household wealth. CONCLUSIONS Submicroscopic malaria infections were associated with fever and non-febrile illness in Ugandan children. These findings support malaria control strategies that target low-density infections.
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Affiliation(s)
- Shereen Katrak
- Department of Medicine, University of California San Francisco, San Francisco, USA.
| | | | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Emmanuel Arinaitwe
- Infectious Diseases Research Collaboration, Kampala, Uganda.,London School of Hygiene and Tropical Medicine, London, UK
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Moses Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Philip J Rosenthal
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, USA
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93
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Parker DM, Landier J, Thu AM, Lwin KM, Delmas G, Nosten FH. Scale up of a Plasmodium falciparum elimination program and surveillance system in Kayin State, Myanmar. Wellcome Open Res 2017; 2:98. [PMID: 29384151 PMCID: PMC5701446 DOI: 10.12688/wellcomeopenres.12741.2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2017] [Indexed: 12/17/2022] Open
Abstract
Background: Myanmar has one of the largest malaria burdens in the Greater Mekong Subregion (GMS). Throughout the GMS,
Plasmodium falciparum parasites are increasingly resistant to artemisinin combination therapies. Given that there are no current alternative treatment therapies, one proposed solution to the threat of untreatable
P. falciparum malaria is to eliminate the parasite from the region. Several small-scale elimination projects have been piloted in the GMS, including along the Myanmar-Thailand border. Following the success of the pilot elimination project along the Myanmar-Thailand border, there was a scale up to a broad area of Eastern Kayin State, Myanmar. Here we describe the establishment of the scale up elimination project in Easter Kayin State. Methods: The scale up relied on geographic reconnaissance and a geographic information system, community engagement, generalized access to community-based early diagnosis and treatment, near real-time epidemiological surveillance, cross sectional malaria prevalence surveys and targeted mass drug administration in villages with high prevalence of
P. falciparum malaria. Molecular markers of drug resistance were also monitored in individuals with symptomatic and asymptomatic infections. Discussion: This protocol illustrates the establishment of an elimination project and operational research in a remote, rural area encompassing several armed groups, multiple political organizations and a near-absent health care infrastructure. The establishment of the project relied on a strong rapport with the target community, on-the-ground knowledge (through geographic surveys and community engagement), rapid decision making and an approach that was flexible enough to quickly adapt to a complex landscape. The elimination project is ongoing, now over three years in operation, and assessment of the impact of this operational research will follow. This project has relevance not only for other malaria elimination projects but also for operational research aimed at eliminating other diseases.
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Affiliation(s)
- Daniel M Parker
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Jordi Landier
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Aung Myint Thu
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Khin Maung Lwin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Gilles Delmas
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - François H Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
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Parker DM, Landier J, Thu AM, Lwin KM, Delmas G, Nosten FH. Scale up of a Plasmodium falciparum elimination program and surveillance system in Kayin State, Myanmar. Wellcome Open Res 2017. [PMID: 29384151 DOI: 10.12688/wellcomeopenres.12741.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Myanmar has one of the largest malaria burdens in the Greater Mekong Subregion (GMS). Throughout the GMS, Plasmodium falciparum parasites are increasingly resistant to artemisinin combination therapies. Given that there are no current alternative treatment therapies, one proposed solution to the threat of untreatable P. falciparum malaria is to eliminate the parasite from the region. Several small-scale elimination projects have been piloted in the GMS, including along the Myanmar-Thailand border. Following the success of the pilot elimination project along the Myanmar-Thailand border, there was a scale up to a broad area of Eastern Kayin State, Myanmar. Here we describe the establishment of the scale up elimination project in Easter Kayin State. Methods: The scale up relied on geographic reconnaissance and a geographic information system, community engagement, generalized access to community-based early diagnosis and treatment, near real-time epidemiological surveillance, cross sectional malaria prevalence surveys and targeted mass drug administration in villages with high prevalence of P. falciparum malaria. Molecular markers of drug resistance were also monitored in individuals with symptomatic and asymptomatic infections. Discussion: This protocol illustrates the establishment of an elimination project and operational research in a remote, rural area encompassing several armed groups, multiple political organizations and a near-absent health care infrastructure. The establishment of the project relied on a strong rapport with the target community, on-the-ground knowledge (through geographic surveys and community engagement), rapid decision making and an approach that was flexible enough to quickly adapt to a complex landscape. The elimination project is ongoing, now over three years in operation, and assessment of the impact of this operational research will follow. This project has relevance not only for other malaria elimination projects but also for operational research aimed at eliminating other diseases.
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Affiliation(s)
- Daniel M Parker
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Jordi Landier
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Aung Myint Thu
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Khin Maung Lwin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Gilles Delmas
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - François H Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
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The detection of cryptic Plasmodium infection among villagers in Attapeu province, Lao PDR. PLoS Negl Trop Dis 2017; 11:e0006148. [PMID: 29261647 PMCID: PMC5754130 DOI: 10.1371/journal.pntd.0006148] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 01/04/2018] [Accepted: 12/02/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Although the malaria burden in the Lao PDR has gradually decreased, the elimination of malaria by 2030 presents many challenges. Microscopy and malaria rapid diagnostic tests (RDTs) are used to diagnose malaria in the Lao PDR; however, some studies have reported the prevalence of sub-microscopic Plasmodium infections or asymptomatic Plasmodium carriers in endemic areas. Thus, highly sensitive detection methods are needed to understand the precise malaria situation in these areas. METHODOLOGY/PRINCIPAL FINDINGS A cross-sectional malaria field survey was conducted in 3 highly endemic malaria districts (Xaysetha, Sanamxay, Phouvong) in Attapeu province, Lao PDR in 2015, to investigate the precise malaria endemicity in the area; 719 volunteers from these villages participated in the survey. Microscopy, RDTs and a real-time nested PCR were used to detect Plasmodium infections and their results were compared. A questionnaire survey of all participants was also conducted to estimate risk factors of Plasmodium infection. Numbers of infections detected by the three methods were microscopy: P. falciparum (n = 1), P. vivax (n = 2); RDTs: P. falciparum (n = 2), P. vivax (n = 3); PCR: Plasmodium (n = 47; P. falciparum [n = 4], P. vivax [n = 41], mixed infection [n = 2]; 6.5%, 47/719). Using PCR as a reference, the sensitivity and specificity of microscopy were 33.3% and 100.0%, respectively, for detecting P. falciparum infection, and 7.0% and 100.0%, for detecting P. vivax infection. Among the 47 participants with parasitemia, only one had a fever (≥37.5°C) and 31 (66.0%) were adult males. Risk factors of Plasmodium infection were males and soldiers, whereas a risk factor of asymptomatic Plasmodium infection was a history of ≥3 malaria episodes. CONCLUSIONS/SIGNIFICANCE There were many asymptomatic Plasmodium carriers in the study areas of Attapeu province in 2015. Adult males, probably soldiers, were at high risk for malaria infection. P. vivax, the dominant species, accounted for 87.2% of the Plasmodium infections among the participants. To achieve malaria elimination in the Lao PDR, highly sensitive diagnostic tests, including PCR-based diagnostic methods should be used, and plans targeting high-risk populations and elimination of P. vivax should be designed and implemented.
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Koepfli C, Ome-Kaius M, Jally S, Malau E, Maripal S, Ginny J, Timinao L, Kattenberg JH, Obadia T, White M, Rarau P, Senn N, Barry AE, Kazura JW, Mueller I, Robinson LJ. Sustained Malaria Control Over an 8-Year Period in Papua New Guinea: The Challenge of Low-Density Asymptomatic Plasmodium Infections. J Infect Dis 2017; 216:1434-1443. [PMID: 29029179 PMCID: PMC5853328 DOI: 10.1093/infdis/jix507] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 09/19/2017] [Indexed: 12/31/2022] Open
Abstract
Background The scale-up of effective malaria control in the last decade has resulted in a substantial decline in the incidence of clinical malaria in many countries. The effects on the proportions of asymptomatic and submicroscopic infections and on transmission potential are yet poorly understood. Methods In Papua New Guinea, vector control has been intensified since 2008, and improved diagnosis and treatment was introduced in 2012. Cross-sectional surveys were conducted in Madang Province in 2006 (with 1280 survey participants), 2010 (with 2117 participants), and 2014 (with 2516 participants). Infections were quantified by highly sensitive quantitative polymerase chain reaction (PCR) analysis, and gametocytes were quantified by reverse-transcription qPCR analysis. Results Plasmodium falciparum prevalence determined by qPCR decreased from 42% in 2006 to 9% in 2014. The P. vivax prevalence decreased from 42% in 2006 to 13% in 2010 but then increased to 20% in 2014. Parasite densities decreased 5-fold from 2006 to 2010; 72% of P. falciparum and 87% of P. vivax infections were submicroscopic in 2014. Gametocyte density and positivity correlated closely with parasitemia, and population gametocyte prevalence decreased 3-fold for P. falciparum and 29% for P. vivax from 2010 to 2014. Conclusions Sustained control has resulted in reduced malaria transmission potential, but an increasing proportion of gametocyte carriers are asymptomatic and submicroscopic and represent a challenge to malaria control.
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Affiliation(s)
- Cristian Koepfli
- Population Health and Immunity Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- University of California–Irvine
| | - Maria Ome-Kaius
- Population Health and Immunity Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- Papua New Guinea Institute of Medical Research, Madang
| | | | - Elisheba Malau
- Population Health and Immunity Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
| | | | - Jason Ginny
- Papua New Guinea Institute of Medical Research, Madang
| | | | - Johanna Helena Kattenberg
- Population Health and Immunity Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Papua New Guinea Institute of Medical Research, Madang
| | - Thomas Obadia
- Malaria: Parasites & Hosts Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
- Bioinformatics and Biostatistics Hub, Center for Bioinformatics, Biostatistics, and Integrative Biology, Institut Pasteur, Paris, France
| | - Michael White
- Population Health and Immunity Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
| | - Patricia Rarau
- School of Population and Global Health, University of Melbourne, Parkville, Australia
- Papua New Guinea Institute of Medical Research, Madang
| | - Nicolas Senn
- Papua New Guinea Institute of Medical Research, Madang
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Alyssa E Barry
- Population Health and Immunity Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
| | | | - Ivo Mueller
- Population Health and Immunity Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- Malaria: Parasites & Hosts Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
- Barcelona Center for International Health, Barcelona, Spain
| | - Leanne J Robinson
- Population Health and Immunity Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- Burnet Institute, Melbourne, Australia
- Papua New Guinea Institute of Medical Research, Madang
- Correspondence: L. Robinson, PhD, MPH, Walter and Eliza Hall Institute, 1G Royal Parade, Parkville VIC 3052, Australia ()
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97
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Katrak S, Murphy M, Nayebare P, Rek J, Smith M, Arinaitwe E, Nankabirwa JI, Kamya M, Dorsey G, Rosenthal PJ, Greenhouse B. Performance of Loop-Mediated Isothermal Amplification for the Identification of Submicroscopic Plasmodium falciparum Infection in Uganda. Am J Trop Med Hyg 2017; 97:1777-1781. [PMID: 29016335 PMCID: PMC5805042 DOI: 10.4269/ajtmh.17-0225] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Accurately identifying and targeting the human reservoir of malaria parasitemia is critical for malaria control, and requires a reliable and sensitive diagnostic method. Loop-mediated isothermal amplification (LAMP) is increasingly used to diagnose submicroscopic parasitemia. Although most published studies report the sensitivity of LAMP compared with nested polymerase chain reaction (PCR) as ≥ 80%, they have failed to use a consistent, sensitive diagnostic as a comparator. We used cross-sectional samples from children and adults in Tororo, Uganda, a region with high but declining transmission due to indoor residual spraying, to characterize the sensitivity and specificity of pan-Plasmodium LAMP for detecting submicroscopic infections. We compared LAMP results targeting a mitochondrial DNA sequence conserved in all Plasmodium species, performed on DNA extracted from dried blood spots, to those of a gold standard quantitative PCR assay targeting the var gene acidic terminal sequence of Plasmodium falciparum (varATS qPCR), performed on DNA extracted from 200 µL of whole blood. Using LAMP and varATS qPCR increased the detection of parasitemia 2- to 5-fold, compared with microscopy. Among microscopy-negative samples, the sensitivity of LAMP was 81.5% for detecting infection ≥ 1 parasites/µL. However, low density infections were common, and LAMP failed to identify more than half of all infections diagnosed by varATS qPCR, performing with an overall sensitivity of 44.7% for detecting submicroscopic infections ≥ 0.01 parasites/µL. Thus, although the LAMP assay is more sensitive than microscopy, it missed a significant portion of the submicroscopic reservoir. These findings have important implications for malaria control, particularly in settings where low-density infections predominate.
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Affiliation(s)
- Shereen Katrak
- Department of Medicine, University of California San Francisco, San Francisco, California;,Address correspondence to Shereen Katrak, Department of Medicine, University of California San Francisco, 513 Parnassus Avenue, Room S380, Box 0654, San Francisco, CA 94143. E-mail:
| | - Maxwell Murphy
- Department of Medicine, University of California San Francisco, San Francisco, California
| | | | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Mary Smith
- Chicago Medical School, Rosalind Franklin University, North Chicago, Illinois
| | - Emmanuel Arinaitwe
- Infectious Diseases Research Collaboration, Kampala, Uganda;,London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Joaniter I. Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda;,School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Moses Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda;,School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California
| | - Philip J. Rosenthal
- Department of Medicine, University of California San Francisco, San Francisco, California
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, California
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Parker DM, Tripura R, Peto TJ, Maude RJ, Nguon C, Chalk J, Sirithiranont P, Imwong M, von Seidlein L, White NJ, Dondorp AM. A multi-level spatial analysis of clinical malaria and subclinical Plasmodium infections in Pailin Province, Cambodia. Heliyon 2017; 3:e00447. [PMID: 29202107 PMCID: PMC5701807 DOI: 10.1016/j.heliyon.2017.e00447] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 10/26/2017] [Accepted: 11/01/2017] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND The malaria burden is decreasing throughout the Greater Mekong Subregion, however transmission persists in some areas. Human movement, subclinical infections and complicated transmission patterns contribute to the persistence of malaria. This research describes the micro-geographical epidemiology of both clinical malaria and subclinical Plasmodium infections in three villages in Western Cambodia. METHODS Three villages in Western Cambodia were selected for the study based on high reported Plasmodium falciparum incidence. A census was conducted at the beginning of the study, including demographic information and travel history. The total population was 1766. Cross-sectional surveys were conducted every three months from June 2013 to June 2014. Plasmodium infections were detected using an ultra-sensitive, high-volume, quantitative polymerase chain reaction (uPCR) technique. Clinical episodes were recorded by village health workers. The geographic coordinates (latitude and longitude) were collected for all houses and all participants were linked to their respective houses using a demographic surveillance system. Written informed consent was obtained from all participants. RESULTS Most clinical episodes and subclinical infections occurred within a single study village. Clinical Plasmodium vivax episodes clustered spatially in each village but only lasted for a month. In one study village subclinical infections clustered in geographic proximity to clusters of clinical episodes. The largest risk factor for clinical P. falciparum episodes was living in a house where another clinical P. falciparum episode occurred (model adjusted odds ratio (AOR): 6.9; CI: 2.3-19. 8). Subclinical infections of both P. vivax and P. falciparum were associated with clinical episodes of the same species (AOR: 5.8; CI: 1.5-19.7 for P. falciparum and AOR: 14.6; CI: 8.6-25.2 for P. vivax) and self-reported overnight visits to forested areas (AOR = 3.8; CI: 1.8-7. 7 for P. falciparum and AOR = 2.9; CI: 1.7-4.8 for P. vivax). DISCUSSION Spatial clustering within the villages was transient, making the prediction of spatial clusters difficult. Interventions that are dependent on predicting spatial clusters (such as reactive case detection) would only have detected a small proportion of cases unless the entire village was screened within a limited time frame and with a highly sensitive diagnostic test. Subclinical infections may be acquired outside of the village (particularly in forested areas) and may play an important role in transmission.
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Affiliation(s)
- Daniel M. Parker
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Thomas J. Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Richard J. Maude
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Harvard University, Boston, USA
| | - Chea Nguon
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Jeremy Chalk
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pasathorn Sirithiranont
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mallika Imwong
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Nicholas J. White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Arjen M. Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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Nguitragool W, Mueller I, Kumpitak C, Saeseu T, Bantuchai S, Yorsaeng R, Yimsamran S, Maneeboonyang W, Sa-Angchai P, Chaimungkun W, Rukmanee P, Puangsa-Art S, Thanyavanich N, Koepfli C, Felger I, Sattabongkot J, Singhasivanon P. Very high carriage of gametocytes in asymptomatic low-density Plasmodium falciparum and P. vivax infections in western Thailand. Parasit Vectors 2017; 10:512. [PMID: 29065910 PMCID: PMC5655986 DOI: 10.1186/s13071-017-2407-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 09/26/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Low-density asymptomatic infections of Plasmodium spp. are common in low endemicity areas worldwide, but outside Africa, their contribution to malaria transmission is poorly understood. Community-based studies with highly sensitive molecular diagnostics are needed to quantify the asymptomatic reservoir of Plasmodium falciparum and P. vivax infections in Thai communities. METHODS A cross-sectional survey of 4309 participants was conducted in three endemic areas in Kanchanaburi and Ratchaburi provinces of Thailand in 2012. The presence of P. falciparum and P. vivax parasites was determined using 18S rRNA qPCR. Gametocytes were also detected by pfs25 / pvs25 qRT-PCRs. RESULTS A total of 133 individuals were found infected with P. vivax (3.09%), 37 with P. falciparum (0.86%), and 11 with mixed P. vivax/ P. falciparum (0.26%). The clear majority of both P. vivax (91.7%) and P. falciparum (89.8%) infections were not accompanied by any febrile symptoms. Infections with either species were most common in adolescent and adult males. Recent travel to Myanmar was highly associated with P. falciparum (OR = 9.0, P = 0.001) but not P. vivax infections (P = 0.13). A large number of P. vivax (71.5%) and P. falciparum (72.0%) infections were gametocyte positive by pvs25/pfs25 qRT-PCR. Detection of gametocyte-specific pvs25 and pfs25 transcripts was strongly dependent on parasite density. pvs25 transcript numbers, a measure of gametocyte density, were also highly correlated with parasite density (r 2 = 0.82, P < 0.001). CONCLUSIONS Asymptomatic infections with Plasmodium spp. were common in western Thai communities in 2012. The high prevalence of gametocytes indicates that these infections may contribute substantially to the maintenance of local malaria transmission.
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Affiliation(s)
- Wang Nguitragool
- Department of Molecular Tropical Medicine & Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ivo Mueller
- Barcelona Centre for International Health Research, Barcelona, Spain.,Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, VIC, Australia.,Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
| | - Chalermpon Kumpitak
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Teerawat Saeseu
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sirasate Bantuchai
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ritthideach Yorsaeng
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Surapon Yimsamran
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wanchai Maneeboonyang
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Patiwat Sa-Angchai
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wutthichai Chaimungkun
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Prasert Rukmanee
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Supalarp Puangsa-Art
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nipon Thanyavanich
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Cristian Koepfli
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, VIC, Australia.,Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
| | - Ingrid Felger
- Department of Medical Parasitology and Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pratap Singhasivanon
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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100
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Huang F, Takala-Harrison S, Liu H, Xu JW, Yang HL, Adams M, Shrestha B, Mbambo G, Rybock D, Zhou SS, Xia ZG, Zhou XN, Plowe CV, Nyunt MM. Prevalence of Clinical and Subclinical Plasmodium falciparum and Plasmodium vivax Malaria in Two Remote Rural Communities on the Myanmar-China Border. Am J Trop Med Hyg 2017; 97:1524-1531. [PMID: 29016341 PMCID: PMC5817756 DOI: 10.4269/ajtmh.17-0167] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Malaria infections may be symptomatic, leading to treatment, or “asymptomatic,” typically detected through active surveillance, and not leading to treatment. Malaria elimination may require purging both types of infection. Using detection methods with different sensitivities, we conducted a cross-sectional study in two rural communities located along the border between China’s Yunnan Province and Myanmar’s Shan and Kachin States, to estimate the prevalence of asymptomatic and symptomatic malaria. In Mong Pawk, all infections detected were asymptomatic, and the prevalence of Plasmodium falciparum was 0.3%, 4.3%, 4.0%, and 7.8% by light microscopy, rapid diagnostic test (RDT), conventional polymerase chain reaction (cPCR), and multiplexed real-time PCR (RT-PCR), respectively, and Plasmodium vivax prevalence was 0% by all detection methods. In Laiza, of 385 asymptomatic participants, 2.3%, 4.4%, and 12.2% were positive for P. vivax by microscopy, cPCR, and RT-PCR, respectively, and 2.3% were P. falciparum-positive only by RT-PCR. Of 34 symptomatic participants in Laiza, 32.4% were P. vivax-positive by all detection methods. Factors associated with infection included gender (males higher than females, P = 0.014), and young age group (5–17 age group compared with others, P = 0.0024). Although the sensitivity of microscopy was adequate to detect symptomatic infections, it missed the vast majority (86.5%) of asymptomatic infections. Although molecular detection methods had no advantage over standard microscopy or RDT diagnosis for clinically apparent infections, malaria elimination along the Myanmar–China border will likely require highly sensitive surveillance tools to identify asymptomatic infections and guide targeted screen-and-treat interventions.
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Affiliation(s)
- Fang Huang
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland.,National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China.,World Health Organization Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, China.,Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, China
| | - Shannon Takala-Harrison
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Hui Liu
- Yunnan Institute of Parasitic Diseases, Pu'er, China
| | - Jian-Wei Xu
- Yunnan Institute of Parasitic Diseases, Pu'er, China
| | - Heng-Lin Yang
- Yunnan Institute of Parasitic Diseases, Pu'er, China
| | - Matthew Adams
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Biraj Shrestha
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Gillian Mbambo
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Demian Rybock
- Department of Geographical Sciences, University of Maryland, College Park, Maryland
| | - Shui-Sen Zhou
- Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, China.,World Health Organization Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, China.,National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Zhi-Gui Xia
- Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, China.,World Health Organization Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, China.,National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Xiao-Nong Zhou
- Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, China.,World Health Organization Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, China.,National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Christopher V Plowe
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Myaing M Nyunt
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland
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