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Thu AM, Phyo AP, Pateekhum C, Rae JD, Landier J, Parker DM, Delmas G, Watthanaworawit W, McLean ARD, Arya A, Reyes A, Li X, Miotto O, Soe K, Ashley EA, Dondorp A, White NJ, Day NP, Anderson TJC, Imwong M, Nosten F, Smithuis F. Molecular markers of artemisinin resistance during falciparum malaria elimination in Eastern Myanmar. Malar J 2024; 23:138. [PMID: 38720269 PMCID: PMC11078751 DOI: 10.1186/s12936-024-04955-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 04/06/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND Artemisinin resistance in Plasmodium falciparum threatens global malaria elimination efforts. To contain and then eliminate artemisinin resistance in Eastern Myanmar a network of community-based malaria posts was instituted and targeted mass drug administration (MDA) with dihydroartemisinin-piperaquine (three rounds at monthly intervals) was conducted. The prevalence of artemisinin resistance during the elimination campaign (2013-2019) was characterized. METHODS Throughout the six-year campaign Plasmodium falciparum positive blood samples from symptomatic patients and from cross-sectional surveys were genotyped for mutations in kelch-13-a molecular marker of artemisinin resistance. RESULT The program resulted in near elimination of falciparum malaria. Of 5162 P. falciparum positive blood samples genotyped, 3281 (63.6%) had K13 mutations. The prevalence of K13 mutations was 73.9% in 2013 and 64.4% in 2019. Overall, there was a small but significant decline in the proportion of K13 mutants (p < 0.001). In the MDA villages there was no significant change in the K13 proportions before and after MDA. The distribution of different K13 mutations changed substantially; F446I and P441L mutations increased in both MDA and non-MDA villages, while most other K13 mutations decreased. The proportion of C580Y mutations fell from 9.2% (43/467) before MDA to 2.3% (19/813) after MDA (p < 0.001). Similar changes occurred in the 487 villages where MDA was not conducted. CONCLUSION The malaria elimination program in Kayin state, eastern Myanmar, led to a substantial reduction in falciparum malaria. Despite the intense use of artemisinin-based combination therapies, both in treatment and MDA, this did not select for artemisinin resistance.
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Affiliation(s)
- Aung Myint Thu
- Shoklo Malaria Research Unit (SMRU), Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University Mae Sot, Bangkok, Thailand
| | - Aung Pyae Phyo
- Shoklo Malaria Research Unit (SMRU), Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University Mae Sot, Bangkok, Thailand.
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK.
| | - Chanapat Pateekhum
- Shoklo Malaria Research Unit (SMRU), Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University Mae Sot, Bangkok, Thailand
| | - Jade D Rae
- Shoklo Malaria Research Unit (SMRU), Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University Mae Sot, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, P. O. Box 10400, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Jordi Landier
- IRD, Aix Marseille Univ, INSERM, SESSTIM, Aix Marseille Institute of Public Health, ISSPAM, Marseille, France
| | - Daniel M Parker
- Department of Population Health and Disease Prevention, Department of Epidemiology & Biostatistics, University of California, Irvine, CE, 92617, USA
| | - Gilles Delmas
- Shoklo Malaria Research Unit (SMRU), Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University Mae Sot, Bangkok, Thailand
| | - Wanitda Watthanaworawit
- Shoklo Malaria Research Unit (SMRU), Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University Mae Sot, Bangkok, Thailand
| | - Alistair R D McLean
- Medical Action Myanmar, Yangon, Myanmar
- Myanmar Oxford Clinical Research Unit (MOCRU), Yangon, Myanmar
| | - Ann Arya
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, P. O. Box 760549, San Antonio, TX, USA
| | - Ann Reyes
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, P. O. Box 760549, San Antonio, TX, USA
| | - Xue Li
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, P. O. Box 760549, San Antonio, TX, USA
| | - Olivo Miotto
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, P. O. Box 10400, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Kyaw Soe
- Medical Action Myanmar, Yangon, Myanmar
- Myanmar Oxford Clinical Research Unit (MOCRU), Yangon, Myanmar
| | - Elizabeth A Ashley
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
- Microbiology Laboratory, Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Mahosot Hospital, Vientiane, Lao PDR
| | - Arjen Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, P. O. Box 10400, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, P. O. Box 10400, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Nicholas P Day
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, P. O. Box 10400, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Tim J C Anderson
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, P. O. Box 760549, San Antonio, TX, USA
| | - Mallika Imwong
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, P. O. Box 10400, Bangkok, Thailand
- Department of Molecular Tropical Medicine and Genetics, Mahidol University, P. O. Box 10400, Bangkok, Thailand
| | - Francois Nosten
- Shoklo Malaria Research Unit (SMRU), Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University Mae Sot, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Frank Smithuis
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, P. O. Box 10400, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
- Medical Action Myanmar, Yangon, Myanmar
- Myanmar Oxford Clinical Research Unit (MOCRU), Yangon, Myanmar
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Sikulu-Lord MT, Edstein MD, Goh B, Lord AR, Travis JA, Dowell FE, Birrell GW, Chavchich M. Rapid and non-invasive detection of malaria parasites using near-infrared spectroscopy and machine learning. PLoS One 2024; 19:e0289232. [PMID: 38527002 PMCID: PMC10962802 DOI: 10.1371/journal.pone.0289232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 12/26/2023] [Indexed: 03/27/2024] Open
Abstract
BACKGROUND Novel and highly sensitive point-of-care malaria diagnostic and surveillance tools that are rapid and affordable are urgently needed to support malaria control and elimination. METHODS We demonstrated the potential of near-infrared spectroscopy (NIRS) technique to detect malaria parasites both, in vitro, using dilutions of infected red blood cells obtained from Plasmodium falciparum cultures and in vivo, in mice infected with P. berghei using blood spotted on slides and non-invasively, by simply scanning various body areas (e.g., feet, groin and ears). The spectra were analysed using machine learning to develop predictive models for infection. FINDINGS Using NIRS spectra of in vitro cultures and machine learning algorithms, we successfully detected low densities (<10-7 parasites/μL) of P. falciparum parasites with a sensitivity of 96% (n = 1041), a specificity of 93% (n = 130) and an accuracy of 96% (n = 1171) and differentiated ring, trophozoite and schizont stages with an accuracy of 98% (n = 820). Furthermore, when the feet of mice infected with P. berghei with parasitaemia ≥3% were scanned non-invasively, the sensitivity and specificity of NIRS were 94% (n = 66) and 86% (n = 342), respectively. INTERPRETATION These data highlights the potential of NIRS technique as rapid, non-invasive and affordable tool for surveillance of malaria cases. Further work to determine the potential of NIRS to detect malaria in symptomatic and asymptomatic malaria cases in the field is recommended including its capacity to guide current malaria elimination strategies.
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Affiliation(s)
- Maggy T. Sikulu-Lord
- School of the Environment, Faculty of Science, The University of Queensland, Brisbane, Queensland, Australia
| | - Michael D. Edstein
- Department of Drug Evaluation, Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Queensland, Australia
| | - Brendon Goh
- School of the Environment, Faculty of Science, The University of Queensland, Brisbane, Queensland, Australia
| | - Anton R. Lord
- Centre for Data Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Jye A. Travis
- Department of Drug Evaluation, Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Queensland, Australia
| | - Floyd E. Dowell
- Center for Grain and Animal Health Research, USDA Agricultural Research Service, Manhattan, Kansas, United States of America
| | - Geoffrey W. Birrell
- Department of Drug Evaluation, Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Queensland, Australia
| | - Marina Chavchich
- Department of Drug Evaluation, Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Queensland, Australia
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Grimée M, Tacoli C, Sandfort M, Obadia T, Taylor AR, Vantaux A, Robinson LJ, Lek D, Longley RJ, Mueller I, Popovici J, White MT, Witkowski B. Using serological diagnostics to characterize remaining high-incidence pockets of malaria in forest-fringe Cambodia. Malar J 2024; 23:49. [PMID: 38360625 PMCID: PMC10870639 DOI: 10.1186/s12936-024-04859-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 01/23/2024] [Indexed: 02/17/2024] Open
Abstract
BACKGROUND Over the last decades, the number of malaria cases has drastically reduced in Cambodia. As the overall prevalence of malaria in Cambodia declines, residual malaria transmission becomes increasingly fragmented over smaller remote regions. The aim of this study was to get an insight into the burden and epidemiological parameters of Plasmodium infections on the forest-fringe of Cambodia. METHODS 950 participants were recruited in the province of Mondulkiri in Cambodia and followed up from 2018 to 2020. Whole-blood samples were processed for Plasmodium spp. identification by PCR as well as for a serological immunoassay. A risk factor analysis was conducted for Plasmodium vivax PCR-detected infections throughout the study, and for P. vivax seropositivity at baseline. To evaluate the predictive effect of seropositivity at baseline on subsequent PCR-positivity, an analysis of P. vivax infection-free survival time stratified by serological status at baseline was performed. RESULTS Living inside the forest significantly increased the odds of P. vivax PCR-positivity by a factor of 18.3 (95% C.I. 7.7-43.5). Being a male adult was also a significant predictor of PCR-positivity. Similar risk profiles were identified for P. vivax seropositivity. The survival analysis showed that serological status at baseline significantly correlated with subsequent infection. Serology is most informative outside of the forest, where 94.0% (95% C.I. 90.7-97.4%) of seronegative individuals survived infection-free, compared to 32.4% (95% C.I.: 22.6-46.6%) of seropositive individuals. CONCLUSION This study justifies the need for serological diagnostic assays to target interventions in this region, particularly in demographic groups where a lot of risk heterogeneity persists, such as outside of the forest.
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Affiliation(s)
- Mathilde Grimée
- Infectious Disease Epidemiology and Analytics, Institut Pasteur, Université Paris Cité, Paris, France.
- Collège Doctoral, Sorbonne Université, Paris, France.
| | - Costanza Tacoli
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Mirco Sandfort
- Collège Doctoral, Sorbonne Université, Paris, France
- Malaria Parasites and Hosts, Institut Pasteur, Université Paris Cité, Paris, France
| | - Thomas Obadia
- Infectious Disease Epidemiology and Analytics, Institut Pasteur, Université Paris Cité, Paris, France
- Bioinformatics and Biostatistics Hub, Institut Pasteur, Université Paris Cité, Paris, France
| | - Aimee R Taylor
- Infectious Disease Epidemiology and Analytics, Institut Pasteur, Université Paris Cité, Paris, France
| | - Amélie Vantaux
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Leanne J Robinson
- Burnet Institute, Melbourne, Australia
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
- Population Health and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Dysoley Lek
- National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
- School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Rhea J Longley
- Population Health and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Ivo Mueller
- Malaria Parasites and Hosts, Institut Pasteur, Université Paris Cité, Paris, France
- Population Health and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Jean Popovici
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Michael T White
- Infectious Disease Epidemiology and Analytics, Institut Pasteur, Université Paris Cité, Paris, France.
- Malaria Parasites and Hosts, Institut Pasteur, Université Paris Cité, Paris, France.
| | - Benoît Witkowski
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
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Assefa A, Fola AA, Tasew G. Emergence of Plasmodium falciparum strains with artemisinin partial resistance in East Africa and the Horn of Africa: is there a need to panic? Malar J 2024; 23:34. [PMID: 38273360 PMCID: PMC10809756 DOI: 10.1186/s12936-024-04848-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 01/10/2024] [Indexed: 01/27/2024] Open
Abstract
The emergence and spread of artemisinin partial resistance in East and Horn of Africa is alarming. However, artemisinin-based combination therapy (ACT) generally remains efficacious for the treatment of falciparum malaria. The emergence of partial artemisinin resistance does not currently meet the criteria to initiate change on treatment guidelines nor affect ACT routine procurement and distribution. It is high time for scientists and transitional researchers to be more critical and vigilant on further changes so that national programmes will be able to make informed decisions as well as remain alert and prepared for any change that may be required in the future.
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Affiliation(s)
- Ashenafi Assefa
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia.
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
| | - Abebe A Fola
- Center for Computational Molecular Biology, Brown University, Providence, RI, USA
| | - Geremew Tasew
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
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St Laurent B. Genomic complexity of parasites and vectors challenges malaria control in Southeast Asia. Curr Opin Insect Sci 2023; 60:101113. [PMID: 37690774 DOI: 10.1016/j.cois.2023.101113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 09/02/2023] [Accepted: 09/05/2023] [Indexed: 09/12/2023]
Abstract
Southeast Asia is a uniquely complex region of malaria transmission that maintains an astounding level of species diversity among potential malaria vectors and also generates drug-resistant and quickly diverging populations of malaria parasites. All five human malaria species circulate in Southeast Asia with over 50 Anopheles species that vary in their ability to transmit these pathogens. The intricate relationships of these parasites and vectors are not well-understood. Human activity in Southeast Asian countries has created an increasingly fragmented landscape, bringing humans and mosquitoes into more frequent contact, sustaining malaria transmission in a region where few control tools are effective. Genomic shifts at the species, population, and individual level in parasites and vectors introduce variation that has produced drug- and insecticide resistance. The goal of this review is to highlight genomic studies of Southeast Asian malaria parasites and vectors that demonstrate how diversity in these organisms presents unique challenges and opportunities for global malaria control and eradication efforts.
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Zaw AS, Win ESS, Yan SW, Thein KS, Verma V, McLean ARD, Kyaw TT, White NJ, Smithuis FM. Successful elimination of falciparum malaria following the introduction of community-based health workers in Eastern Myanmar: A retrospective analysis. PLoS Med 2023; 20:e1004318. [PMID: 38033155 PMCID: PMC10721164 DOI: 10.1371/journal.pmed.1004318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 12/14/2023] [Accepted: 11/03/2023] [Indexed: 12/02/2023] Open
Abstract
BACKGROUND Myanmar has a large majority of all malaria in the Greater Mekong Subregion. In the past decade, substantial progress was made in malaria control. The residual burden of malaria is in remote areas where currently recommended malaria elimination approaches are generally not feasible. In such hard-to-reach communities in Mon state, East Myanmar, Medical Action Myanmar introduced community health workers (CHWs) to deliver early diagnosis and treatment for malaria. We conducted a retrospective analysis to assess the impact of this intervention. METHODS AND FINDINGS This retrospective analysis involved data collected routinely from a CHW programme in Mon state conducted between 2011 and 2018. A network of 172 CHWs serving a population of 236,340 was deployed. These CHWs carried out 260,201 malaria rapid diagnostic tests (RDTs) to investigate patients with acute febrile illness. The median blood examination rate was 1.33%; interquartile range (IQR) (0.38 to 3.48%); 95% CI [1.28%, 1.36%] per month. The changes in malaria incidence and prevalence in patients presenting with fever were assessed using negative binomial regression mixed effects models fitted to the observed data. The incidence of Plasmodium falciparum malaria (including mixed infections) declined by 70%; 95% CI [65%, 75%]; p < 0.001 for each year of CHW operation. The incidence of P. vivax malaria declined by 56%; 95% CI [50%, 62%]; p < 0.001 per year. Malaria RDT positivity rates for P. falciparum and P. vivax declined by 69%; 95% CI [62%, 75%]; p < 0.001 and 53%; 95% CI [47%, 59%]; p < 0.001 per year, respectively. Between 2017 and 2018, only 1 imported P. falciparum case was detected in 54,961 RDTs. The main limitations of the study are use of retrospective data with possible unidentified confounders and uncharacterised population movement. CONCLUSIONS The introduction of CHWs providing community-based malaria diagnosis and treatment and basic health care services in remote communities in Mon state was associated with a substantial reduction in malaria. Within 6 years, P. falciparum was eliminated and the incidence of P. vivax fell markedly.
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Affiliation(s)
- Aye Sandar Zaw
- Medical Action Myanmar, Yangon, Myanmar
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
| | | | | | | | | | - Alistair R. D. McLean
- Medical Action Myanmar, Yangon, Myanmar
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
| | - Thar Tun Kyaw
- Medical Action Myanmar, Yangon, Myanmar
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
- Department of Public Health, Ministry of Health and Sports, Nay Pyi Taw, Myanmar
| | - Nicholas J. White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Frank M. Smithuis
- Medical Action Myanmar, Yangon, Myanmar
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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Naserrudin NA, Jiee SF, Habil B, Jantim A, Mohamed AFB, Dony JJF, Ibrahim SSA, Fornace KM, Hassan MR, Jeffree MS, Hod R, Culleton R, Ahmed K. The public health response to a Plasmodium malariae outbreak in Penampang district, Sabah during a COVID-19 movement control order. Malar J 2023; 22:292. [PMID: 37789320 PMCID: PMC10546630 DOI: 10.1186/s12936-023-04693-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 08/29/2023] [Indexed: 10/05/2023] Open
Abstract
BACKGROUND Since 2018, no indigenous human malaria cases has been reported in Malaysia. However, during the recent COVID-19 pandemic the World Health Organization is concerned that the pandemic might erode the success of malaria control as there are reports of increase malaria cases in resource limited countries. Little is known how the COVID-19 pandemic has impacted malaria in middle-income countries like Malaysia. Here the public health response to a Plasmodium malariae outbreak occurred in a village in Sabah state, Malaysia, during a COVID-19 movement control order is reported. METHODS An outbreak was declared following the detection of P. malariae in July 2020 and active case detection for malaria was performed by collecting blood samples from residents residing within 2 km radius of Moyog village. Vector prevalence and the efficacy of residual insecticides were determined. Health awareness programmes were implemented to prevent future outbreaks. A survey was conducted among villagers to understand risk behaviour and beliefs concerning malaria. RESULTS A total of 5254 blood samples collected from 19 villages. Among them, 19 P. malariae cases were identified, including the index case, which originated from a man who returned from Indonesia. His return from Indonesia and healthcare facilities visit coincided with the movement control order during COVID-19 pandemic when the healthcare facilities stretched its capacity and only serious cases were given priority. Despite the index case being a returnee from a malaria endemic area presenting with mild fever, no malaria test was performed at local healthcare facilities. All cases were symptomatic and uncomplicated except for a pregnant woman with severe malaria. There were no deaths; all patients recovered following treatment with artemether-lumefantrine combination therapy. Anopheles balabacensis and Anopheles barbirostris were detected in ponds, puddles and riverbeds. The survey revealed that fishing and hunting during night, and self-treatment for mild symptoms contributed to the outbreak. Despite the index case being a returnee from a malaria-endemic area presenting with mild fever, no malaria test was performed at local healthcare facilities. CONCLUSION The outbreak occurred during a COVID-19 movement control order, which strained healthcare facilities, prioritizing only serious cases. Healthcare workers need to be more aware of the risk of malaria from individuals who return from malaria endemic areas. To achieve malaria elimination and prevention of disease reintroduction, new strategies that include multisectoral agencies and active community participation are essential for a more sustainable malaria control programme.
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Affiliation(s)
- Nurul Athirah Naserrudin
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Malaysia
- Sabah State Health Department, Ministry of Health, Kota Kinabalu, Malaysia
| | - Sam Froze Jiee
- Department of Community Medicine and Public Health, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Kota Samarahan, Malaysia
| | - Bobby Habil
- Penampang District Health Office, Ministry of Health, Kota Kinabalu, Malaysia
| | - Anisah Jantim
- Penampang District Health Office, Ministry of Health, Kota Kinabalu, Malaysia
| | | | | | | | - Kimberly M Fornace
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
- Faculty of Infectious and Tropical Diseases and Centre for Climate Change and Planetary Health, London School of Hygiene and Tropical Medicine, London, UK
- Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore, Singapore
| | - Mohd Rohaizat Hassan
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Malaysia
| | - Mohammad Saffree Jeffree
- Department of Public Health Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Malaysia
| | | | - Kamruddin Ahmed
- Borneo Medical Health and Research Centre,, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia.
- Department of Pathology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia.
- Research Center for Global and Local Infectious Diseases, Oita University, Oita, Japan.
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Hoffman-Hall A, Puett R, Silva JA, Chen D, Bredder A, Shevade V, Han ZY, Han KT, Aung PP, Plowe CV, Nyunt MM, Loboda TV. Comparison of deforestation and forest land use factors for malaria elimination in Myanmar. IJID Reg 2023; 8:75-83. [PMID: 37533552 PMCID: PMC10393544 DOI: 10.1016/j.ijregi.2023.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 08/04/2023]
Abstract
Objectives Within the remote region of Ann Township in Myanmar's Rakhine State, malaria prevalence has remained steady at ∼10% of the population from 2016-2019. Previous studies have linked areas of higher malaria prevalence in the region to heavily forested areas, however, little is known about how people live, work, and move through these areas. This work aims to disentangle landscape from land use in regard to malaria exposure. Methods We investigated the roles of forest cover, forest loss, and land use activities with malaria prevalence through the combined use of land use surveys, malaria surveillance, and satellite earth observations. Results Our results confirm previous research that linked areas of high forest cover with high malaria prevalence. However, areas experiencing high levels of deforestation were not associated with malaria prevalence. The land use factors that contribute most significantly to increased malaria risk remained those which put people in direct contact with forests, including conducting forest chores, having an outdoor job, and having a primary occupation in the logging and/or plantation industry. Conclusion Malaria prevention methods in Myanmar should focus on anyone who lives near forests or engages in land use activities that bring them within proximity of forested landscapes, whether through occupation or chores.
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Affiliation(s)
| | - Robin Puett
- University of Maryland, School of Public Health, College Park, USA
| | - Julie A. Silva
- University at Buffalo, Department of Geography, Buffalo, USA
| | - Dong Chen
- University of Maryland, Department of Geographical Sciences, College Park, USA
| | - Allison Bredder
- University of Maryland, Department of Geographical Sciences, College Park, USA
| | - Varada Shevade
- University of Maryland, Department of Geographical Sciences, College Park, USA
| | - Zay Yar Han
- Duke University, Global Health Institute, Durham, USA
| | - Kay Thwe Han
- Department of Medical Research, Myanmar Ministry of Health and Sports, Yangon, Myanmar
| | - Poe Poe Aung
- Malaria Consortium, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Tatiana V. Loboda
- University of Maryland, Department of Geographical Sciences, College Park, USA
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Byrne I, William T, Chua TH, Patterson C, Hall T, Tan M, Chitnis C, Adams J, Singh SK, Grignard L, Tetteh KKA, Fornace KM, Drakeley CJ. Serological evaluation of risk factors for exposure to malaria in a pre-elimination setting in Malaysian Borneo. Sci Rep 2023; 13:12998. [PMID: 37563178 PMCID: PMC10415323 DOI: 10.1038/s41598-023-39670-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 07/28/2023] [Indexed: 08/12/2023] Open
Abstract
Malaysia has reported no indigenous cases of P. falciparum and P. vivax for over 3 years. When transmission reaches such low levels, it is important to understand the individuals and locations where exposure risks are high, as they may be at greater risk in the case of a resurgence of transmission. Serology is a useful tool in low transmission settings, providing insight into exposure over longer durations than PCR or RDT. We ran blood samples from a 2015 population-based survey in northern Sabah, Malaysian Borneo on a multiplex bead assay. Using supervised machine learning methods, we characterised recent and historic exposure to Plasmodium falciparum and P. vivax and found recent exposure to P. falciparum to be very low, with exposure to both species increasing with age. We performed a risk-factor assessment on environmental, behavioural, demographic and household factors, and identified forest activity and longer travel times to healthcare as common risk-factors for exposure to P. falciparum and P. vivax. In addition, we used remote-sensing derived data and geostatistical models to assess environmental and spatial associations with exposure. We created predictive maps of exposure to recent P. falciparum in the study area and showed 3 clear foci of exposure. This study provides useful insight into the environmental, spatial and demographic risk factors for P. falciparum and P. vivax at a period of low transmission in Malaysian Borneo. The findings would be valuable in the case of resurgence of human malarias in the region.
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Affiliation(s)
- Isabel Byrne
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK.
| | - Timothy William
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Malaysia
- Gleneagles Hospital, Kota Kinabalu, Malaysia
- Clinical Research Centre, Queen Elizabeth Hospital, Kota Kinabalu, Malaysia
| | - Tock H Chua
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Catriona Patterson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK
| | - Tom Hall
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK
| | - Mark Tan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK
| | - Chetan Chitnis
- Department of Parasites and Insect Vectors, Malaria Parasite Biology and Vaccines, Institut Pasteur, Paris, France
| | - John Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Susheel K Singh
- Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Lynn Grignard
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK
| | - Kevin K A Tetteh
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK
| | - Kimberly M Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, Scotland
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Chris J Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK
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Kotepui M, Kotepui KU, Masangkay FR, Mahittikorn A, Wilairatana P. Prevalence and proportion estimate of asymptomatic Plasmodium infection in Asia: a systematic review and meta-analysis. Sci Rep 2023; 13:10379. [PMID: 37369862 DOI: 10.1038/s41598-023-37439-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 06/21/2023] [Indexed: 06/29/2023] Open
Abstract
Asymptomatic Plasmodium infection raises a problem for the persistent transmission of malaria in low-endemic areas such as Asia. This systematic review was undertaken to estimate the prevalence and proportion of asymptomatic Plasmodium infection in Asia. The systematic review was registered at PROSPERO (ID: CRD42022373664). The research followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A comprehensive search of five databases, Ovid, Scopus, MEDLINE, PubMed, and Embase, was conducted to identify studies of asymptomatic Plasmodium infection in Asian countries. The pooled prevalence of asymptomatic Plasmodium infection, the pooled proportion of asymptomatic Plasmodium infection among all parasitised individuals, and the associated 95% confidence intervals were estimated using a random-effects model. A total of 916 articles were retrieved, and 87 articles that met the criteria were included in the systematic review. The pooled prevalence of asymptomatic Plasmodium infection among enrolled participants in Southeast Asia, South Asia, and Western Asia was 5.8%, 9.4%, and 8.4%, respectively. The pooled proportion of asymptomatic Plasmodium infection among all parasitised individuals in Southeast Asia, South Asia, and Western Asia was 89.3%, 87.2%, and 64.8%, respectively. There was a low prevalence of asymptomatic Plasmodium infection, but there was a high proportion of asymptomatic Plasmodium infection per all parasitised individuals in different parts of Asia. These results may support and facilitate elimination and control programs for asymptomatic Plasmodium infection in Asia.
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Affiliation(s)
- Manas Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand.
| | - Kwuntida Uthaisar Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | | | - Aongart Mahittikorn
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Polrat Wilairatana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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11
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Doum D, Mclver DJ, Hustedt J, Hii J, Sovannaroth S, Lek D, Richardson JH, Tatarsky A, Lobo NF. An active and targeted survey reveals asymptomatic malaria infections among high-risk populations in Mondulkiri, Cambodia. Malar J 2023; 22:193. [PMID: 37353790 DOI: 10.1186/s12936-023-04630-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023] Open
Abstract
BACKGROUND Malaria is a mosquito-borne disease that is one of the most serious public health issues globally and a leading cause of mortality in many developing countries worldwide. Knowing the prevalence of both symptomatic and asymptomatic malaria on a subnational scale allows for the estimation of the burden of parasitaemia present in the transmission system, enabling targeting and tailoring of resources towards greater impact and better use of available capacity. This study aimed to determine the PCR-based point prevalence of malaria infection, by parasite species, among three high-risk populations in Mondulkiri province, Cambodia: forest rangers, forest dwellers, and forest goers. METHODS A cross-sectional survey was performed during the transmission season in November and December 2021. Blood samples collected on filter paper from participants (n = 1301) from all target groups were screened for Plasmodium spp using PCR. RESULTS Malaria prevalence among all study participants was 6.7% for any Plasmodium species. Malaria prevalence in the forest ranger group was 8.1%, was 6.8% in forest goers, and 6.4% in forest dwellers; all infections were asymptomatic. Plasmodium vivax was detected in all participant groups, while the few Plasmodium falciparum infections were found in goers and dwellers. 81% of all infections were due to P. vivax, 9% were due to P. falciparum, 3% due to Plasmodium cynomolgi, and the rest (7%) remained undefined. Gender was associated with malaria infection prevalence, with male participants having higher odds of malaria infection than female participants (OR = 1.69, 95% CI 1.08-2.64). Passively collected malaria incidence data from the Cambodian government were also investigated. Health facility-reported malaria cases, based on rapid diagnostic tests, for the period Jan-Dec 2021 were 521 Plasmodium vivax (0.89% prevalence), 34 P. falciparum (0.06%) and four P. falciparum + mixed (0.01%)-a total of 559 cases (0.95%) for all of Mondulkiri. CONCLUSION This reservoir of asymptomatic parasitaemia may be perpetuating low levels of transmission, and thus, new strategies are required to realize the goal of eliminating malaria in Cambodia by 2025.
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Affiliation(s)
- Dyna Doum
- Health Forefront Organization, Phnom Penh, Cambodia
| | - David J Mclver
- Malaria Elimination Initiative, University of California, San Francisco, CA, USA.
| | - John Hustedt
- Health Forefront Organization, Phnom Penh, Cambodia
| | - Jeffrey Hii
- Malaria Elimination Initiative, University of California, San Francisco, CA, USA
| | - Siv Sovannaroth
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Dysoley Lek
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - Allison Tatarsky
- Malaria Elimination Initiative, University of California, San Francisco, CA, USA
| | - Neil F Lobo
- Malaria Elimination Initiative, University of California, San Francisco, CA, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, USA
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12
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Amaral LC, Salazar YEAR, de Alvarenga DAM, de Pina-Costa A, Nunes AJD, de Souza Junior JC, Gonçalves GHP, Hirano ZMB, Moreira SB, Pissinatti A, Daniel-Ribeiro CT, de Sousa TN, Alves de Brito CF. Detection of Plasmodium simium gametocytes in non-human primates from the Brazilian Atlantic Forest. Malar J 2023; 22:170. [PMID: 37268984 DOI: 10.1186/s12936-023-04601-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/20/2023] [Indexed: 06/04/2023] Open
Abstract
BACKGROUND Plasmodium species of non-human primates (NHP) are of great interest because they can naturally infect humans. Plasmodium simium, a parasite restricted to the Brazilian Atlantic Forest, was recently shown to cause a zoonotic outbreak in the state of Rio de Janeiro. The potential of NHP to act as reservoirs of Plasmodium infection presents a challenge for malaria elimination, as NHP will contribute to the persistence of the parasite. The aim of the current study was to identify and quantify gametocytes in NHP naturally-infected by P. simium. METHODS Whole blood samples from 35 NHP were used in quantitative reverse transcription PCR (RT-qPCR) assays targeting 18S rRNA, Pss25 and Pss48/45 malaria parasite transcripts. Absolute quantification was performed in positive samples for 18S rRNA and Pss25 targets. Linear regression was used to compare the quantification cycle (Cq) and the Spearman's rank correlation coefficient was used to assess the correlation between the copy numbers of 18S rRNA and Pss25 transcripts. The number of gametocytes/µL was calculated by applying a conversion factor of 4.17 Pss25 transcript copies per gametocyte. RESULTS Overall, 87.5% of the 26 samples, previously diagnosed as P. simium, were positive for 18S rRNA transcript amplification, of which 13 samples (62%) were positive for Pss25 transcript amplification and 7 samples (54%) were also positive for Pss48/45 transcript. A strong positive correlation was identified between the Cq of the 18S rRNA and Pss25 and between the Pss25 and Pss48/45 transcripts. The 18S rRNA and Pss25 transcripts had an average of 1665.88 and 3.07 copies/µL, respectively. A positive correlation was observed between the copy number of Pss25 and 18S rRNA transcripts. Almost all gametocyte carriers exhibited low numbers of gametocytes (< 1/µL), with only one howler monkey having 5.8 gametocytes/µL. CONCLUSIONS For the first time, a molecular detection of P. simium gametocytes in the blood of naturally-infected brown howler monkeys (Alouatta guariba clamitans) was reported here, providing evidence that they are likely to be infectious and transmit P. simium infection, and, therefore, may act as a reservoir of malaria infection for humans in the Brazilian Atlantic Forest.
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Affiliation(s)
- Lara Cotta Amaral
- Grupo de Pesquisa em Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz (Fiocruz), Belo Horizonte, Brazil
| | | | - Denise Anete Madureira de Alvarenga
- Grupo de Pesquisa em Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz (Fiocruz), Belo Horizonte, Brazil
| | - Anielle de Pina-Costa
- Laboratório de Doenças Febris Agudas, Instituto Nacional de Infectologia Evandro Chagas, Fiocruz, Rio de Janeiro, Brazil
- Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Rio de Janeiro, Brazil
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
- Departamento de Doenças Infecciosas e Parasitárias, Escola de Enfermagem Aurora de Afonso Costa, Universidade Federal Fluminense, Niterói, Brazil
| | - Ana Júlia Dutra Nunes
- Programa de Conservação do Bugio Ruivo, Joinville, Brazil
- Centro de Pesquisas Biológicas de Indaial, Indaial, Brazil
- Universidade Regional de Blumenau - FURB, Blumenau, Brazil
| | - Júlio Cesar de Souza Junior
- Centro de Pesquisas Biológicas de Indaial, Indaial, Brazil
- Universidade Regional de Blumenau - FURB, Blumenau, Brazil
| | | | - Zelinda Maria Braga Hirano
- Centro de Pesquisas Biológicas de Indaial, Indaial, Brazil
- Universidade Regional de Blumenau - FURB, Blumenau, Brazil
| | | | - Alcides Pissinatti
- Centro de Primatologia do Rio de Janeiro/INEA, Guapimirim, Brazil
- Centro Universitário Serra dos Órgãos, Teresópolis, Brazil
| | - Cláudio Tadeu Daniel-Ribeiro
- Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Rio de Janeiro, Brazil
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Taís Nóbrega de Sousa
- Grupo de Pesquisa em Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz (Fiocruz), Belo Horizonte, Brazil
| | - Cristiana Ferreira Alves de Brito
- Grupo de Pesquisa em Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz (Fiocruz), Belo Horizonte, Brazil.
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13
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Sirimatayanant M, Hein PS, Anderson LF, Montoya LF, Potter R, Nghipumbwa M, Ranaweera P, Ngor P, Phetsouvanh R, Maude RJ. Gaps in research and capacity development for malaria surveillance and response in the Asia-Pacific: meeting report. Malar J 2023; 22:91. [PMID: 36899358 PMCID: PMC10000341 DOI: 10.1186/s12936-023-04459-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 01/14/2023] [Indexed: 03/12/2023] Open
Abstract
BACKGROUND This report is based on the 2021 annual meeting of the Asia-Pacific Malaria Elimination Network Surveillance and Response Working Group held online on November 1-3, 2021. In light of the 2030 regional malaria elimination goal, there is an urgency for Asia-Pacific countries to accelerate progress towards national elimination and prevent re-establishment. The Asia Pacific Malaria Elimination Network (APMEN) Surveillance Response Working Group (SRWG) supports elimination goals of national malaria control programmes (NMCPs) by expanding the knowledge base, guiding the region-specific operational research agenda and addressing evidence gaps to improve surveillance and response activities. METHODS An online annual meeting was hosted from 1 to 3 November 2021, to reflect on research needed to support malaria elimination in the region, challenges with malaria data quality and integration, current surveillance-related technical tools, and training needs of NMCPs to support surveillance and response activities. Facilitator-led breakout groups were held during meeting sessions to encourage discussion and share experience. A list of identified research priorities was voted on by attendees and non-attending NMCP APMEN contacts. FINDINGS 127 participants from 13 country partners and 44 partner institutions attended the meeting, identifying strategies to address malaria transmission amongst mobile and migrant populations as the top research priority, followed by cost effective surveillance strategies in low resource settings, and integration of malaria surveillance into broader health systems. Key challenges, solutions and best practices for improving data quality and integrating epidemiology and entomology data were identified, including technical solutions to improve surveillance activities, guiding priority themes for hosting informative webinars, training workshops and technical support initiatives. Inter-regional partnerships and SRWG-led training plans were developed in consultation with members to be launched from 2022 onwards. CONCLUSION The 2021 SRWG annual meeting provided an opportunity for regional stakeholders, both NMCPs and APMEN partner institutions, to highlight remaining challenges and barriers and identify research priorities pertaining to surveillance and response in the region, and advocate for strengthening capacity through training and supportive partnerships.
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Affiliation(s)
- Massaya Sirimatayanant
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Phone Si Hein
- Asia Pacific Malaria Elimination Network (APMEN), Singapore, Singapore
| | - Laura Fay Anderson
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | | | | | | | | | - Pengby Ngor
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - 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 Medicine, University of Oxford, Oxford, UK. .,Harvard TH Chan School of Public Health, Harvard University, Boston, USA. .,The Open University, Milton Keynes, UK.
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Naserrudin NA, Hassan MR, Jeffree MS, Culleton R, Hod R, Ahmed K. A systematic review of asymptomatic Plasmodium knowlesi infection: an emerging challenge involving an emerging infectious disease. Malar J 2022; 21:373. [PMID: 36474243 PMCID: PMC9724390 DOI: 10.1186/s12936-022-04339-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 10/18/2022] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND In the last decade Plasmodium knowlesi has been detected in humans throughout South East Asia. The highest risk groups for this infection are males, adults and those performing forest-related work. Furthermore, asymptomatic cases of P. knowlesi malaria have been reported including among women and children. METHODS Pubmed, Scopus and the Web of Science databases for literature describing asymptomatic P. knowlesi malaria published between 2010 and 2020 were searched. A systematic literature review was conducted to identify studies reporting the prevalence and incidence of laboratory confirmed asymptomatic P. knowlesi cases in humans, their clinical and demographic characteristics, and methods used to diagnose these cases. RESULTS By analysing over 102 papers, thirteen were eligible for this review. Asymptomatic P. knowlesi infections have been detected in 0.03%-4.0% of the population depending on region, and infections have been described in children as young as 2 years old. Various different diagnostic methods were used to detect P. knowlesi cases and there were differing definitions of asymptomatic cases in these studies. The literature indicates that regionally-differing immune-related mechanisms may play a part on the prevalence of asymptomatic P. knowlesi. CONCLUSION Differing epidemiological characteristics of asymptomatic P. knowlesi malaria in different regions reinforces the need to further investigate disease transmission mechanics. Effective public health responses to changes in P. knowlesi epidemiology require proactive intervention and multisectoral collaboration.
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Affiliation(s)
- Nurul Athirah Naserrudin
- grid.412113.40000 0004 1937 1557Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia ,grid.265727.30000 0001 0417 0814Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia, Sabah, Kota Kinabalu, Malaysia ,grid.415759.b0000 0001 0690 5255Sabah State Health Department, Ministry of Health, Kota Kinabalu, Malaysia
| | - Mohd Rohaizat Hassan
- grid.412113.40000 0004 1937 1557Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia ,grid.265727.30000 0001 0417 0814Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia, Sabah, Kota Kinabalu, Malaysia
| | - Mohammad Saffree Jeffree
- grid.265727.30000 0001 0417 0814Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia, Sabah, Kota Kinabalu, Malaysia ,grid.265727.30000 0001 0417 0814Department of Community and Family Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Richard Culleton
- grid.255464.40000 0001 1011 3808Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Japan
| | - Rozita Hod
- grid.412113.40000 0004 1937 1557Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Kamruddin Ahmed
- grid.265727.30000 0001 0417 0814Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia, Sabah, Kota Kinabalu, Malaysia ,grid.265727.30000 0001 0417 0814Department of Pathology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
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Turnbull LB, Ayodo G, Knight V, John CC, McHenry MS, Tran TM. Evaluation of an ultrasensitive HRP2–based rapid diagnostic test for detection of asymptomatic Plasmodium falciparum parasitaemia among children in western Kenya. Malar J 2022; 21:337. [DOI: 10.1186/s12936-022-04351-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 10/21/2022] [Indexed: 11/17/2022] Open
Abstract
Abstract
Background
Accurate detection of asymptomatic malaria parasitaemia in children living in high transmission areas is important for malaria control and reduction programmes that employ screen-and-treat surveillance strategies. Relative to microscopy and conventional rapid diagnostic tests (RDTs), ultrasensitive RDTs (us-RDTs) have demonstrated reduced limits of detection with increased sensitivity to detect parasitaemia in symptomatic individuals. In this study, the performance of the NxTek™ Eliminate Malaria P.f test was compared with traditional microscopy and quantitative polymerase chain reaction (qPCR) testing methods of detection for P. falciparum parasitaemia among asymptomatic children aged 7–14 years living in an area of high malaria transmission intensity in western Kenya.
Methods
In October 2020, 240 healthy children without any reported malaria symptoms were screened for the presence of P. falciparum parasitaemia; 120 children were randomly selected to participate in a follow-up visit at 6–10 weeks. Malaria parasitaemia was assessed by blood-smear microscopy, us-RDT, and qPCR of a conserved var gene sequence from genomic DNA extracted from dried blood spots. Sensitivity, specificity, and predictive values were calculated for field diagnostic methods using qPCR as the gold standard. Comparison of detectable parasite density distributions and area under the curve were also calculated to determine the effectiveness of the us-RDT in detecting asymptomatic infections with low parasite densities.
Results
The us-RDT detected significantly more asymptomatic P. falciparum infections than microscopy (42.5% vs. 32.2%, P = 0.002). The positive predictive value was higher for microscopy (92.2%) than for us-RDT (82.4%). However, false negative rates were high for microscopy and us-RDT, with negative predictive values of 53.7% and 54.6%, respectively. While us-RDT detected significantly more infections than microscopy overall, the density distribution of detectable infections did not differ (P = 0.21), and qPCR detected significantly more low-density infections than both field methods (P < 0.001, for both comparisons).
Conclusions
Us-RDT is more sensitive than microscopy for detecting asymptomatic malaria parasitaemia in children. Though the detectable parasite density distributions by us-RDT in our specific study did not significantly differ from microscopy, the additional sensitivity of the us-RDT resulted in more identified asymptomatic infections in this important group of the population and makes the use of the us-RDT advisable compared to other currently available malaria field detection methods.
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Rahim MAFA, Chuangchaiya S, Chanpum P, Palawong L, Kantee P, Dian ND, Lubis IND, Divis PCS, Kaneko A, Tetteh KKA, Idris ZM. Seroepidemiological surveillance, community perceptions and associated risk factors of malaria exposure among forest-goers in Northeastern Thailand. Front Cell Infect Microbiol 2022; 12:953585. [PMID: 36093204 PMCID: PMC9450859 DOI: 10.3389/fcimb.2022.953585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/03/2022] [Indexed: 12/02/2022] Open
Abstract
Malaria remains a major public health challenge in Thailand. Continuous assessment and understanding of the behavior and perceptions related to malaria exposure in the high-risk group are necessary to achieve the elimination goal. This study aimed to investigate the parasite prevalence, seroprevalence rate, knowledge, attitudes, and practices (KAP), and malaria risk factors in rural communities living close to a forested area in the northeastern part of Thailand. A community-based cross-sectional survey was conducted in three forest-goer communities (i.e., Ban Khok, Ban Koh, and Dong Yang) located in Khamcha-i district, Mukdahan Province, Thailand, from July to August 2019. Demographic, socioeconomic information and KAP data were collected using a structured questionnaire. Parasite prevalence was determined by microscopy. Seroprevalence was determined via ELISA using two Plasmodium falciparum (PfAMA-1 and PfMSP-119) and two Plasmodium vivax (PvAMA-1 and PvMSP-119) antigens. Age-adjusted antibody responses were analyzed using a reversible catalytic model to calculate seroconversion rate (SCR). Malaria parasite was not detected in any of the 345 participants. The overall malaria seroprevalence was 72.2% for PfAMA-1, 18.8% for PfMSP-119, 32.5% for PvAMA-1, and 4.4% for PvMSP-119. The proportion of seroprevalence for P. falciparum and P. vivax antigens was significantly highest in Ban Koh (35.1%, P < 0.001) and Don Yang (18.8%, P < 0.001), respectively. For all parasite antigens except PvMSP-119, the proportion of seropositive individuals significantly increased with age (P < 0.001). Based on the SCRs, there was a higher level of P. falciparum transmission than P. vivax. Regarding KAP, almost all respondents showed adequate knowledge and awareness about malaria. Nevertheless, significant effort is needed to improve positive attitudes and practices concerning malaria prevention measures. Multivariate regression analyses showed that living in Ban Koh was associated with both P. falciparum (adjusted odds ratio [aOR] 12.87, P < 0.001) and P. vivax (aOR 9.78, P < 0.001) seropositivities. We also found significant associations between age and seropositivity against P. falciparum and P. vivax antigens. The data suggest that seroepidemiological surveillance using AMA-1 and MSP-119 antigens may provide further evidence to reconstruct malaria exposure history. The absence of weak evidence of recent malaria transmission in Mukdahan Province is promising in the context of the disease elimination program.
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Affiliation(s)
- Mohd Amirul Fitri A. Rahim
- Deparment of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Sriwipa Chuangchaiya
- Faculty of Public Health, Kasetsart University, Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon, Thailand
- *Correspondence: Zulkarnain Md Idris, ; Sriwipa Chuangchaiya,
| | - Paisit Chanpum
- Vector Borne Disease Unit, Ban Koh Sub-District Health Promoting Hospital, Mukdahan, Thailand
| | - Laun Palawong
- Vector Borne Disease Unit, Ban Koh Sub-District Health Promoting Hospital, Mukdahan, Thailand
| | - Panuwat Kantee
- Vector Borne Disease Unit, Ban Koh Sub-District Health Promoting Hospital, Mukdahan, Thailand
| | - Nor Diyana Dian
- Deparment of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Inke Nadia D. Lubis
- Department of Paediatric, Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia
| | - Paul C. S. Divis
- Malaria Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Kota Samarahan, Sarawak, Malaysia
| | - Akira Kaneko
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Department of Parasitology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Kevin K. A. Tetteh
- Department of Infection Biology, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Zulkarnain Md Idris
- Deparment of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
- *Correspondence: Zulkarnain Md Idris, ; Sriwipa Chuangchaiya,
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Byrne I, Cramer E, Nelli L, Rerolle F, Wu L, Patterson C, Rosado J, Dumont E, Tetteh KKA, Dantzer E, Hongvanthong B, Fornace KM, Stresman G, Lover A, Bennett A, Drakeley C. Characterizing the spatial distribution of multiple malaria diagnostic endpoints in a low-transmission setting in Lao PDR. Front Med (Lausanne) 2022; 9:929366. [PMID: 36059850 PMCID: PMC9433740 DOI: 10.3389/fmed.2022.929366] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/22/2022] [Indexed: 11/21/2022] Open
Abstract
The epidemiology of malaria changes as prevalence falls in low-transmission settings, with remaining infections becoming more difficult to detect and diagnose. At this stage active surveillance is critical to detect residual hotspots of transmission. However, diagnostic tools used in active surveillance generally only detect concurrent infections, and surveys may benefit from sensitive tools such as serological assays. Serology can be used to interrogate and characterize individuals' previous exposure to malaria over longer durations, providing information essential to the detection of remaining foci of infection. We ran blood samples collected from a 2016 population-based survey in the low-transmission setting of northern Lao PDR on a multiplexed bead assay to characterize historic and recent exposures to Plasmodium falciparum and vivax. Using geostatistical methods and remote-sensing data we assessed the environmental and spatial associations with exposure, and created predictive maps of exposure within the study sites. We additionally linked the active surveillance PCR and serology data with passively collected surveillance data from health facility records. We aimed to highlight the added information which can be gained from serology as a tool in active surveillance surveys in low-transmission settings, and to identify priority areas for national surveillance programmes where malaria risk is higher. We also discuss the issues faced when linking malaria data from multiple sources using multiple diagnostic endpoints.
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Affiliation(s)
- Isabel Byrne
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- *Correspondence: Isabel Byrne
| | - Estee Cramer
- Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts-Amherst, Amherst, MA, United States
| | - Luca Nelli
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Francois Rerolle
- Malaria Elimination Initiative, The Global Health Group, University of California, San Francisco, San Francisco, CA, United States
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, United States
| | - Lindsey Wu
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Catriona Patterson
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jason Rosado
- Unit of Malaria: Parasites and Hosts, Institut Pasteur, Paris, France
- Infectious Diseases Epidemiology and Analytics G5 Unit, Institut Pasteur, Paris, France
| | - Elin Dumont
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Kevin K. A. Tetteh
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Emily Dantzer
- Malaria Elimination Initiative, The Global Health Group, University of California, San Francisco, San Francisco, CA, United States
| | - Bouasy Hongvanthong
- Center for Malariology, Parasitology and Entomology, Ministry of Health, Vientiane, Laos
| | - Kimberley M. Fornace
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Gillian Stresman
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Andrew Lover
- Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts-Amherst, Amherst, MA, United States
| | - Adam Bennett
- Malaria Elimination Initiative, The Global Health Group, University of California, San Francisco, San Francisco, CA, United States
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, United States
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
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18
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Han KT, Han ZY, Zainabadi K. Developing Molecular Surveillance Capacity for Asymptomatic and Drug-Resistant Malaria in a Resource-Limited Setting-Experiences and Lessons Learned. Am J Trop Med Hyg 2022; 107:222-230. [PMID: 35895423 PMCID: PMC9393433 DOI: 10.4269/ajtmh.21-0543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 10/15/2021] [Indexed: 08/03/2023] Open
Abstract
The COVID-19 pandemic has highlighted the important role molecular surveillance plays in public health. Such capacity however is either weak or nonexistent in many low-income countries. This article outlines a 2-year effort to establish two high-throughput molecular surveillance laboratories in Myanmar for tracking asymptomatic and drug resistant Plasmodium falciparum malaria. The lessons learned from this endeavor may prove useful for others seeking to establish similar molecular surveillance capacity in other resource-limited settings.
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Affiliation(s)
- Kay Thwe Han
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Zay Yar Han
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Kayvan Zainabadi
- Center for Global Health, Weill Cornell Medicine, New York, New York
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19
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Egger JR, Han KT, Fang H, Zhou XN, Hlaing TM, Thant M, Han ZY, Wang XX, Hong T, Platt A, Simmons R, Thane TK, Meng M, Hogue J, Markwalter CF, Thi A, Htay T, Thein ZW, Paing AK, Tun ZM, Oo SM, Aung PP, Nyunt MM, Plowe CV. Temporal Dynamics of Subclinical Malaria in Different Transmission Zones of Myanmar. Am J Trop Med Hyg 2022; 107:tpmd220027. [PMID: 35895341 PMCID: PMC9490656 DOI: 10.4269/ajtmh.22-0027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/19/2022] [Indexed: 12/03/2022] Open
Abstract
Countries in the Greater Mekong Subregion have committed to eliminate Plasmodium falciparum malaria by 2025. Subclinical malaria infections that can be detected by highly sensitive polymerase chain reaction (PCR) testing in asymptomatic individuals represent a potential impediment to this goal, although the extent to which these low-density infections contribute to transmission is unclear. To understand the temporal dynamics of subclinical malaria in this setting, a cohort of 2,705 participants from three epidemiologically distinct regions of Myanmar was screened for subclinical P. falciparum and P. vivax infection using ultrasensitive PCR (usPCR). Standard rapid diagnostic tests (RDTs) for P. falciparum were also performed. Individuals who tested positive for malaria by usPCR were followed for up to 12 weeks. Regression analysis was performed to estimate whether the baseline prevalence of infection and the count of repeated positive tests were associated with demographic, behavioral, and clinical factors. At enrollment, the prevalence of subclinical malaria infection measured by usPCR was 7.7% (1.5% P. falciparum monoinfection, 0.3% mixed P. falciparum and P. vivax, and 6.0% P. vivax monoinfection), while P. falciparum prevalence measured by RDT was just 0.2%. Prevalence varied by geography and was higher among older people and in those with outdoor exposure and travel. No difference was observed in either the prevalence or count of subclinical infection by time of year, indicating that even in low-endemicity areas, a reservoir of subclinical infection persists year-round. If low-density infections are shown to represent a significant source of transmission, identification of high-risk groups and locations may aid elimination efforts.
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Affiliation(s)
- Joseph R. Egger
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Kay T. Han
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Huang Fang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Xiao Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China
| | - Tin M. Hlaing
- Defense Services Medical Research Center, Nay Pyi Taw, Myanmar
| | - Myo Thant
- Defense Services Medical Research Center, Nay Pyi Taw, Myanmar
| | - Zay Y. Han
- Duke Global Health Institute, Duke University, Durham, North Carolina
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Xiao X. Wang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Tu Hong
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Alyssa Platt
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | | | - Thynn K. Thane
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Manfred Meng
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Joyce Hogue
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | | | - Aung Thi
- National Malaria Control Program, Myanmar Ministry of Health and Sports, Nay Pyi Taw, Myanmar
| | - Thura Htay
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Zaw W. Thein
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Aye K. Paing
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Zin M. Tun
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Swai M. Oo
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Poe P. Aung
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Myaing M. Nyunt
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Christopher V. Plowe
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
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20
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Abebaw A, Aschale Y, Kebede T, Hailu A. The prevalence of symptomatic and asymptomatic malaria and its associated factors in Debre Elias district communities, Northwest Ethiopia. Malar J 2022; 21:167. [PMID: 35659661 PMCID: PMC9166605 DOI: 10.1186/s12936-022-04194-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 05/21/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria is a major cause of morbidity and mortality worldwide. According to the World Health Organization 2021 malaria report, it is considered to be endemic in 85 countries and territories. Malaria elimination programmes have also faced many challenges, such as widespread asymptomatic carriers in endemic regions, and they should be considered in malaria-control programmes in endemic areas for successful transmission interruption. This study aimed to assess the prevalence of symptomatic and asymptomatic malaria infections, and associated factors in Debre Elias district communities, Northwest Ethiopia from May to Jun 2018. METHODS A community-based cross-sectional study was conducted among selected kebeles in Debre Elias district, Amhara region, North-western Ethiopia. Multi-stage sampling technique was carried out to select representative households. A total of 440 randomly selected households were included, of which one individual per household was sampled for laboratory examination. Malaria prevalence was determined by light microscopy of stained blood films and using CareStart™ Malaria HRP2/pLDH (Pf/Pv) Combo rapid diagnostic test (RDT). A structured questionnaire was employed to collect socio-demographic data and associated risk factors. Data entry and analysis were carried out using Epi data 3.1 and SPSS version 23 software, respectively. The association between dependent and independent variables was explored by using bivariate and multivariate logistic regression analyses. Statistically significant association was declared at P-value of < 0.05. RESULTS A total of 440 (333 asymptomatic and 107 symptomatic) individuals were included in this study. The overall prevalence of malaria was 5% with the majority (59.1%) of infections caused by Plasmodium falciparum. Among asymptomatic participants, 4.8% (n = 16, 95% CI = 2.6-7.3) and 4.2% (n = 14, 95% CI = 2.1-6.5) were diagnosed and confirmed by RDT and light microscopy respectively. Similarly, the prevalence of malaria among 107 symptomatic individuals was 7.5% (n = 8, 95% CI = 2.8-12.6) by either RDT or light microscopy. Utilization of insecticide-treated net (ITN), availability of ITN, house with eave, previous history of malaria infection, and family history of malaria infection were significantly associated with malaria infection (P < 0.05). CONCLUSION In this study, the prevalence of asymptomatic and symptomatic malaria was moderate. Screening of both symptomatic and asymptomatic malaria in the community is very important to scale up intervention programmes.
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Affiliation(s)
- Abtie Abebaw
- Department of Medical Laboratory Science, College of Health Sciences, Debre Markos University, P.O. Box: 269, Debre Markos, Ethiopia.
| | - Yibeltal Aschale
- Department of Medical Laboratory Science, College of Health Sciences, Debre Markos University, P.O. Box: 269, Debre Markos, Ethiopia
| | - Tadesse Kebede
- Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Asrat Hailu
- Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
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21
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Abstract
The countries of the Greater Mekong subregion-Myanmar, Thailand, Laos, Cambodia, and Vietnam-have set a target of eliminating all Plasmodium falciparum malaria by 2025. Generous funding has been provided, principally by The Global Fund to Fight AIDS, Tuberculosis, and Malaria, to achieve this objective and thereby prevent the spread of artemisinin-resistant Plasmodium falciparum to India and Africa. As the remaining time to reach agreed targets is limited and future external funding is uncertain, it is important to be realistic about the future and spend what remaining funding is left, wisely. New, labour intensive, vertical approaches to malaria elimination (such as the 1-3-7 approach) should not be promoted as these are unproven, likely to be ineffective, costly, and unlikely to be sustainable in the most remote areas where malaria prevalence is highest. Instead, the focus should be on reducing the malaria burden more rapidly in the remaining localised high transmission foci with proven effective interventions, including mass drug administration. Well supported community-based health workers are the key operatives in controlling malaria, but their remit should be broadened to sustain the uptake of their services as malaria declines. This strategy is a sustainable evolution, which will improve rural health care while ensuring progress towards malaria elimination.
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Affiliation(s)
- Frank M Smithuis
- Medical Action Myanmar, Yangon, Myanmar; Myanmar Oxford Clinical Research Unit, Yangon, Myanmar; Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Nicholas J White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK; Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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22
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Melese Y, Alemu M, Yimer M, Tegegne B, Tadele T. Asymptomatic Malaria in Households and Neighbors of Laboratory Confirmed Cases in Raya Kobo District, Northeast Ethiopia. Ethiop J Health Sci 2022; 32:623-630. [PMID: 35813680 PMCID: PMC9214748 DOI: 10.4314/ejhs.v32i3.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 02/13/2022] [Indexed: 11/17/2022] Open
Abstract
Background Malaria is the leading vector-borne parasitic disease that is causing high morbidity and mortality worldwide. So far huge efforts to control and eliminate malaria are hindered by the occurrence of asymptomatic carriers that are a potential source of infection. Yet, there is a scarcity of data nationally and in the current study area as well. Therefore, this study was aimed to assess the prevalence of asymptomatic malaria in Northeast Ethiopia. Methods A community-based cross-sectional study was conducted in 2019 involving a total of 270 study participants recruited via purposive non-probability sampling technique. A structured questionnaire was used to collect data on sociodemographic characteristics, individual and household factors related to asymptomatic malaria. Data were entered in Epi Data 3.1 version and analyzed by using SPSS version 20, and p< 0.05 was considered statistically significant. Results The overall prevalence of asymptomatic malaria was 7.0%, with 3.0%, 5.2%, and 12.0%, respectively by Rapid diagnostic tests (RDT), Microscopy and Polymerase chain reaction (PCR). The majority of infections (73.7%) were identified from index households. Previous malaria history (AOR: 4.030, 95% CI: 1.021-15.903), living with index cases (AOR: 3.880, 95% CI: 1.275-11.806) and family size > 6 members (AOR: 4.820, 95% CI: 1.260-18.437) were significant predictors of asymptomatic malaria. Conclusion Reactive case detection had identified considerably higher asymptomatic malaria cases in the community. Therefore, active case investigation should be established in the community by tracking the symptomatic cases at the health facilities.
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Affiliation(s)
| | - Megbaru Alemu
- Department of Medical Laboratory Science, College of Medicine and Health Sciences, Bahir Dar University, Ethiopia
| | - Mulat Yimer
- Department of Medical Laboratory Science, College of Medicine and Health Sciences, Bahir Dar University, Ethiopia
| | | | - Tigist Tadele
- Department of Biomedical Sciences, College of Medicine and Health Sciences, Bahir Dar University, Ethiopia
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23
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San NN, Kien NX, Manh ND, Van Thanh N, Chavchich M, Binh NTH, Long TK, Edgel KA, Rovira-Vallbona E, Edstein MD, Martin NJ. Cross-sectional study of asymptomatic malaria and seroepidemiological surveillance of seven districts in Gia Lai province, Vietnam. Malar J 2022; 21:40. [PMID: 35135536 PMCID: PMC8822839 DOI: 10.1186/s12936-022-04060-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 01/23/2022] [Indexed: 11/12/2022] Open
Abstract
Background Malaria elimination by 2030 is an aim of many countries in the Greater Mekong Sub-region, including Vietnam. However, to achieve this goal and accelerate towards malaria elimination, countries need to determine the extent and prevalence of asymptomatic malaria as a potential reservoir for malaria transmission and the intensity of malaria transmission. The purpose of this study was to determine the prevalence of asymptomatic malaria and seropositivity rate in several districts of Gia Lai province in the Central Highlands of Vietnam. Methods A cross-sectional survey of asymptomatic malaria and serological testing was conducted in 3283 people living at 14 communes across seven districts in Gia Lai province in December 2016 to January 2017. Finger prick capillary blood samples were tested for malaria using rapid diagnostic testing and polymerase chain reaction (PCR), as well as detecting antibodies against 3 Plasmodium falciparum and 4 Plasmodium vivax antigens by indirect enzyme-linked immunosorbent assay (ELISA). Age-seroprevalence curves were fitted using reverse catalytic models with maximum likelihood. Results The study population was predominantly male (65.9%, 2165/3283), adults (88.7%, 2911/3283) and of a minority ethnicity (72.2%, 2371/3283), with most participants being farmers and outdoor government workers (90.2%, 2960/3283). Using a small volume of blood (≈ 10 µL) the PCR assay revealed that 1.74% (57/3283) of the participants had asymptomatic malaria (P. falciparum 1.07%, P. vivax 0.40%, Plasmodium malariae 0.15% and mixed infections 0.12%). In contrast, the annual malaria prevalence rates for clinical malaria in the communities where the participants lived were 0.12% (108/90,395) in 2016 and 0.22% (201/93,184) in 2017. Seropositivity for at least one P. falciparum or one P. vivax antigen was 38.5% (1257/3262) and 31.1% (1022/3282), respectively. Age-dependent trends in the proportion of seropositive individuals in five of the districts discriminated the three districts with sustained low malaria prevalence from the two districts with higher transmission. Conclusions Asymptomatic Plasmodium carriers were found to be substantially more prevalent than clinical cases in seven districts of Gia Lai province, and a third of the population had serological evidence of previous malaria exposure. The findings add knowledge on the extent of asymptomatic malaria and transmission for developing malaria elimination strategies for Vietnam. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04060-6.
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Affiliation(s)
| | - Nguyen Xuan Kien
- Vietnam People's Army Military Medical Department, Hanoi, Vietnam
| | - Nguyen Duc Manh
- Vietnam People's Army Military Institute of Preventive Medicine, Hanoi, Vietnam
| | - Nguyen Van Thanh
- Vietnam People's Army Military Institute of Preventive Medicine, Hanoi, Vietnam
| | - Marina Chavchich
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
| | | | | | | | | | - Michael D Edstein
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
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Abstract
BACKGROUND Plasmodium vivax infects an estimated 7 million people every year. Previously, vivax malaria was perceived as a benign condition, particularly when compared to falciparum malaria. Reports of the severe clinical impacts of vivax malaria have been increasing over the last decade. METHODS AND FINDINGS We describe the main clinical impacts of vivax malaria, incorporating a rapid systematic review of severe disease with meta-analysis of data from studies with clearly defined denominators, stratified by hospitalization status. Severe anemia is a serious consequence of relapsing infections in children in endemic areas, in whom vivax malaria causes increased morbidity and mortality and impaired school performance. P. vivax infection in pregnancy is associated with maternal anemia, prematurity, fetal loss, and low birth weight. More than 11,658 patients with severe vivax malaria have been reported since 1929, with 15,954 manifestations of severe malaria, of which only 7,157 (45%) conformed to the World Health Organization (WHO) diagnostic criteria. Out of 423 articles, 311 (74%) were published since 2010. In a random-effects meta-analysis of 85 studies, 68 of which were in hospitalized patients with vivax malaria, we estimated the proportion of patients with WHO-defined severe disease as 0.7% [95% confidence interval (CI) 0.19% to 2.57%] in all patients with vivax malaria and 7.11% [95% CI 4.30% to 11.55%] in hospitalized patients. We estimated the mortality from vivax malaria as 0.01% [95% CI 0.00% to 0.07%] in all patients and 0.56% [95% CI 0.35% to 0.92%] in hospital settings. WHO-defined cerebral, respiratory, and renal severe complications were generally estimated to occur in fewer than 0.5% patients in all included studies. Limitations of this review include the observational nature and small size of most of the studies of severe vivax malaria, high heterogeneity of included studies which were predominantly in hospitalized patients (who were therefore more likely to be severely unwell), and high risk of bias including small study effects. CONCLUSIONS Young children and pregnant women are particularly vulnerable to adverse clinical impacts of vivax malaria, and preventing infections and relapse in this groups is a priority. Substantial evidence of severe presentations of vivax malaria has accrued over the last 10 years, but reporting is inconsistent. There are major knowledge gaps, for example, limited understanding of the underlying pathophysiology and the reason for the heterogenous geographical distribution of reported complications. An adapted case definition of severe vivax malaria would facilitate surveillance and future research to better understand this condition.
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Affiliation(s)
| | - Prabin Dahal
- Infectious Diseases Data Observatory–IDDO, Oxford, United Kingdom
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Mayfong Mayxay
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Institute of Research and Education Development (IRED), University of Health Sciences, Ministry of Health, Vientiane, Laos
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Mahosot Hospital, Vientiane, Laos
| | - Elizabeth A. Ashley
- 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, Mahosot Hospital, Vientiane, Laos
- * E-mail:
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25
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Jongdeepaisal M, Ean M, Heng C, Buntau T, Tripura R, Callery JJ, Peto TJ, Conradis-Jansen F, von Seidlein L, Khonputsa P, Pongsoipetch K, Soviet U, Sovannaroth S, Pell C, Maude RJ. Acceptability and feasibility of malaria prophylaxis for forest goers: findings from a qualitative study in Cambodia. Malar J 2021; 20:446. [PMID: 34823527 PMCID: PMC8613728 DOI: 10.1186/s12936-021-03983-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 11/12/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND In the Greater Mekong Subregion, adults are at highest risk for malaria, particularly those who visit forests. The absence of effective vector control strategies and limited periods of exposure during forest visits suggest that chemoprophylaxis could be an appropriate strategy to protect forest goers against malaria. METHODS Alongside a clinical trial of anti-malarial chemoprophylaxis in northern Cambodia, qualitative research was conducted, including in-depth interviews and observation, to explore the acceptability of malaria prophylaxis for forest goers, the implementation opportunities, and challenges of this strategy. RESULTS Prophylaxis with artemether-lumefantrine for forest goers was found to be acceptable under trial conditions. Three factors played a major role: the community's awareness and perception of the effectiveness of prophylaxis, their trust in the provider, and malaria as a local health concern. The findings highlight how uptake and adherence to prophylaxis are influenced by the perceived balance between benefits and burden of anti-malarials which are modulated by the seasonality of forest visits and its influence on malaria risk. CONCLUSIONS The implementation of anti-malarial prophylaxis needs to consider how the preventive medication can be incorporated into existing vector-control measures, malaria testing and treatment services. The next step in the roll out of anti-malarial prophylaxis for forest visitors will require support from local health workers.
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Affiliation(s)
- Monnaphat Jongdeepaisal
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Mom Ean
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chhoeun Heng
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thoek Buntau
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rupam Tripura
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - James J. Callery
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Thomas J. Peto
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Franca Conradis-Jansen
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lorenz von Seidlein
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Panarasri Khonputsa
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kulchada Pongsoipetch
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ung Soviet
- Provincial Health Department, Stung Treng, Stung Treng Cambodia
| | - Siv Sovannaroth
- grid.452707.3National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Christopher Pell
- grid.450091.90000 0004 4655 0462Amsterdam Institute for Global Health and Development (AIGHD), Amsterdam, The Netherlands ,grid.509540.d0000 0004 6880 3010Department of Global Health, Amsterdam University Medical Centers - Location Academic Medical Center, Amsterdam, The Netherlands ,grid.7177.60000000084992262Centre for Social Science and Global Health, University of Amsterdam, Amsterdam, The Netherlands
| | - Richard J. Maude
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.38142.3c000000041936754XHarvard TH Chan School of Public Health, Harvard University, Boston, USA ,grid.10837.3d0000000096069301The Open University, Milton Keynes, UK
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Zeng W, Zhao H, Zhao W, Yang Q, Li X, Li X, Duan M, Wang X, Li C, Xiang Z, Chen X, Cui L, Yang Z. Molecular Surveillance and Ex Vivo Drug Susceptibilities of Plasmodium vivax Isolates From the China-Myanmar Border. Front Cell Infect Microbiol 2021; 11:738075. [PMID: 34790586 PMCID: PMC8591282 DOI: 10.3389/fcimb.2021.738075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/06/2021] [Indexed: 11/18/2022] Open
Abstract
Drug resistance in Plasmodium vivax may pose a challenge to malaria elimination. Previous studies have found that P. vivax has a decreased sensitivity to antimalarial drugs in some areas of the Greater Mekong Sub-region. This study aims to investigate the ex vivo drug susceptibilities of P. vivax isolates from the China–Myanmar border and genetic variations of resistance-related genes. A total of 46 P. vivax clinical isolates were assessed for ex vivo susceptibility to seven antimalarial drugs using the schizont maturation assay. The medians of IC50 (half-maximum inhibitory concentrations) for chloroquine, artesunate, and dihydroartemisinin from 46 parasite isolates were 96.48, 1.95, and 1.63 nM, respectively, while the medians of IC50 values for piperaquine, pyronaridine, mefloquine, and quinine from 39 parasite isolates were 19.60, 15.53, 16.38, and 26.04 nM, respectively. Sequence polymorphisms in pvmdr1 (P. vivax multidrug resistance-1), pvmrp1 (P. vivax multidrug resistance protein 1), pvdhfr (P. vivax dihydrofolate reductase), and pvdhps (P. vivax dihydropteroate synthase) were determined by PCR and sequencing. Pvmdr1 had 13 non-synonymous substitutions, of which, T908S and T958M were fixed, G698S (97.8%) and F1076L (93.5%) were highly prevalent, and other substitutions had relatively low prevalences. Pvmrp1 had three non-synonymous substitutions, with Y1393D being fixed, G1419A approaching fixation (97.8%), and V1478I being rare (2.2%). Several pvdhfr and pvdhps mutations were relatively frequent in the studied parasite population. The pvmdr1 G698S substitution was associated with a reduced sensitivity to chloroquine, artesunate, and dihydroartemisinin. This study suggests the possible emergence of P. vivax isolates resistant to certain antimalarial drugs at the China–Myanmar border, which demands continuous surveillance for drug resistance.
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Affiliation(s)
- Weilin Zeng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Hui Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Wei Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Qi Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Xinxin Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Xiaosong Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Mengxi Duan
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Xun Wang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Cuiying Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Zheng Xiang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Xi Chen
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
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Bantuchai S, Imad H, Nguitragool W. Plasmodium vivax gametocytes and transmission. Parasitol Int 2021; 87:102497. [PMID: 34748969 DOI: 10.1016/j.parint.2021.102497] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 08/14/2021] [Accepted: 10/30/2021] [Indexed: 10/19/2022]
Abstract
Malaria elimination means cessation of parasite transmission. At present, the declining malaria incidence in many countries has made elimination a feasible goal. Transmission control has thus been placed at the center of the national malaria control programs. The efficient transmission of Plasmodium vivax from humans to mosquitoes is a key factor that helps perpetuate malaria in endemic areas. A better understanding of transmission is crucial to the success of elimination efforts. Biological delineation of the parasite transmission process is important for identifying and prioritizing new targets of intervention. Identification of the infectious parasite reservoir in the community is key to devising an effective elimination strategy. Here we describe the fundamental characteristics of P. vivax gametocytes - the dynamics of their production, longevity, and the relationship with the total parasitemia - as well as recent advances in the molecular understanding of parasite sexual development. In relation to malaria elimination, factors influencing the human infectivity and the current evidence for a role of asymptomatic carriers in transmission are presented.
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Affiliation(s)
- Sirasate Bantuchai
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.
| | - Hisham Imad
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.
| | - Wang Nguitragool
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand; Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.
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28
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Quang HH, Chavchich M, Trinh NTM, Manh ND, Edstein MD, Martin NJ, Edgel KA. Cross-sectional survey of asymptomatic malaria in Dak Nong province in the Central Highlands of Vietnam for the malaria elimination roadmap. PLoS One 2021; 16:e0258580. [PMID: 34669697 PMCID: PMC8528296 DOI: 10.1371/journal.pone.0258580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 09/30/2021] [Indexed: 12/25/2022] Open
Abstract
Asymptomatic parasite carriers represent a “silent” infective reservoir for malaria transmission and contributes to malaria persistence. However, limited data are available on asymptomatic malaria in Vietnam. Between November 2018 and March 2019, we conducted a malaria epidemiological survey of asymptomatic people (children ≥ 10 years old and adults ≥18 years old, n = 2,809) residing in three communes in Tuy Duc district, Dak Nong province in the Central Highlands of Vietnam. Based on the national stratification of malaria risk, Dak Buk So, Dak Ngo and Quang Truc communes were classified by the National Malaria Control Programme as low, moderate and high malaria endemic areas, respectively. Using participants’ finger prick blood samples, malaria parasites were detected by one-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The median age (Interquartile Range) for adults and children were 35 years (26–50) and 12 years (11–14), respectively. The prevalence of asymptomatic malaria was 1.7% (22/1,328), 3.5% (31/890) and 12.2% (72/591) for participants from Dak Buk So, Dak Ngo and Quang Truc, respectively. The prevalence of asymptomatic malaria was lower in children compared to adults: 2.6% (9/352) versus 4.7% (116/2,457) (Odds Ratio 0.53, 95% Confidence Interval 0.28 to1.02). Ownership of long-lasting insecticide-treated bed nets and hammocks was 97.1%, 99.0% and 94.7% for participants in Dak Buk So, Dak Ngo and Quang Truc, respectively, however, only 66.0%, 57.3% and 42.8% of the participants reported using bed nets every night. Of the several risk factors examined, going to the forest two weeks prior to enrolment into the study and sleeping in the forest had a significant association with participants being infected with asymptomatic malaria in Quang Truc, but not in the other two communes. Knowledge of the prevalence and distribution of asymptomatic malaria will help design and evaluate future intervention strategies for malaria elimination in Vietnam.
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Affiliation(s)
- Huynh Hong Quang
- Institute of Malariology, Parasitology and Entomology, Quy Nhon, Vietnam
| | - Marina Chavchich
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
- * E-mail:
| | | | | | - Michael D. Edstein
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
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29
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Maude RJ, Tripura R, Ean M, Sokha M, Peto TJ, Callery JJ, Imwong M, Vongpromek R, Tarning J, Mukaka M, Waithira N, Soviet O, von Seidlein L, Sovannaroth S. Study protocol: an open-label individually randomised controlled trial to assess the efficacy of artemether-lumefantrine prophylaxis for malaria among forest goers in Cambodia. BMJ Open 2021; 11:e045900. [PMID: 34233975 PMCID: PMC8264911 DOI: 10.1136/bmjopen-2020-045900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 06/15/2021] [Indexed: 12/02/2022] Open
Abstract
INTRODUCTION In the Greater Mekong Subregion, adults are at highest risk for malaria. The most relevant disease vectors bite during daytime and outdoors which makes forest work a high-risk activity for malaria. The absence of effective vector control strategies and limited periods of exposure during forest visits suggest that chemoprophylaxis could be an appropriate strategy to protect forest goers against malaria. METHODS AND ANALYSIS The protocol describes an open-label randomised controlled trial of artemether-lumefantrine (AL) versus multivitamin as prophylaxis against malaria among forest goers aged 16-65 years in rural northeast Cambodia. The primary objective is to compare the efficacy of the artemisinin combination therapy AL versus a multivitamin preparation as defined by the 28-day PCR parasite positivity rate and incidence of confirmed clinical malaria of any species. The sample size is 2200 patient-episodes of duration 1 month in each arm. The duration of follow-up and prophylaxis for each participant is 1, 2 or 3 consecutive 28-day periods, followed by a further 28 days of post-exposure prophylaxis, depending on whether they continue to visit the forest. Analysis will be done both by intention to treat and per protocol. ETHICS AND DISSEMINATION All participants will provide written, informed consent. Ethical approval was obtained from the Oxford Tropical Research Ethics Committee and the Cambodia National Ethics Committee for Health Research. Results will be disseminated by peer-reviewed open access publication together with open data. TRIAL REGISTRATION NUMBER NCT04041973; Pre-result.
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Affiliation(s)
- Richard James 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 TH Chan School of Public Health, Harvard University, Boston, MA, USA
- The Open University, Milton Keynes, 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
| | - Mom Ean
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Meas Sokha
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thomas Julian 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
| | - James John Callery
- 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
| | - 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
| | - Ranitha Vongpromek
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Asia-Pacific Regional Centre, WorldWide Antimalarial Resistance Network, Bangkok, Thailand
| | - 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, Oxford, UK
| | - 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, UK
| | - Naomi Waithira
- 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
| | - Oung Soviet
- Provincial Health Department, Stung Treng, Cambodia
| | - 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
| | - Siv Sovannaroth
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
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Han KT, Han ZY, Aye KH, Wai KT, Thi A, Cui L, Sattabongkot J. G6PD deficiency among malaria-infected national groups at the western part of Myanmar with implications for primaquine use in malaria elimination. Trop Med Health 2021; 49:47. [PMID: 34108049 PMCID: PMC8191138 DOI: 10.1186/s41182-021-00339-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 05/31/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Glucose 6-phosphate dehydrogenase deficiency (G6PDd) plays a central role in readiness assessment for malaria elimination in Myanmar by 2030 that includes primaquine (PQ) use. The risk of hemolysis in G6PDd individuals hampers the widespread use of primaquine safely in malaria-infected patients. In the pre-elimination era, it is important to screen initially for asymptomatic malaria in combination with G6PD deficiency by applying more sensitive diagnostic tools. Therefore, this study examined the proportion of G6PDd and the distribution of G6PD genotypes among malaria-infected national groups in Myanmar before initiation of malaria elimination strategies. METHODS A cross-sectional study in one township each with high malaria burden from two states in the western part of Myanmar, was conducted during 2016-2018, and 320 participants (164 Rakhine and 156 Chin National groups) were recruited. We used RDT and ultrasensitive polymerase chain reaction (us PCR) method to confirm malaria infection, and a G6PD RDT(CareStart) to detect G6PDd and PCR/restriction fragment length polymorphism (RFLP) method to confirm the variant of G6PDd for genotyping. G6PD enzyme activity was measured by G6PD Biosensor (CareStart). RESULTS Malaria positivity rates detected by RDT were lower than those detected by us PCR in the combined samples [13% (42/320) vs. 21% (67/320)] as well as in the Rakhine samples [17% (28/164) vs. 25% (41/164)] and in Chin samples [9% (14/156) vs. 17% (26/156)]. G6PD deficiency rates were approximately 10% in both the combined samples and specific national groups. For G6PD enzyme activity in the combined samples, G6PDd (defined as < 30% of adjusted male median) was 10% (31/320) and severe G6PDd (< 10% of AMM) was 3% (9/320). Among malaria-infected patients with positive by both RDT and usPCR, G6PDd was less than 20% in each national group. G6PD genotyping showed that the G6PD Mahidol (G487A) was the major variant. CONCLUSIONS The varying degree of G6PDd detected among malaria-infected national groups by advanced diagnostic tools, strongly support the recommend G6PD testing by the National Malaria Control Program and the subsequent safe treatment of P. vivax by primaquine for radical cure. Establishing a field monitoring system to achieve timely malaria elimination is mandatory to observe the safety of patients after PQ treatment.
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Affiliation(s)
- Kay Thwe Han
- grid.415741.2Parasitology Research Division, Department of Medical Research (DMR), No. 5 Ziwaka Road, Yangon, 11191 Myanmar
| | - Zay Yar Han
- DMR, No. 5 Ziwaka Road, Yangon, 11191 Myanmar
| | - Kyin Hla Aye
- grid.415741.2Parasitology Research Division, Department of Medical Research (DMR), No. 5 Ziwaka Road, Yangon, 11191 Myanmar
| | | | - Aung Thi
- National Malaria Control Program, Department of Public Health (DoPH), Naypyitaw, Myanmar
| | - Liwang Cui
- grid.170693.a0000 0001 2353 285XDepartment of Internal Medicine, University of South Florida, Tampa, USA
| | - Jetsumon Sattabongkot
- grid.10223.320000 0004 1937 0490Mahidol Vivax Research Unit (MVRU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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31
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Ean M, Sanann N, Callery JJ, Pell C, Peto TJ, Tripura R, Cheah PY. Theory of change: Drama and arts-based community engagement for malaria research and elimination in Cambodia. Wellcome Open Res 2021; 6:46. [PMID: 34041367 PMCID: PMC8127021 DOI: 10.12688/wellcomeopenres.16574.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2021] [Indexed: 11/21/2022] Open
Abstract
Background: Across the Greater Mekong Sub-region, malaria persists in isolated communities along international borders. Arts and drama have been used to reach to communities in Cambodia to engage them in malaria research, prevention and control. The “Village Drama Against Malaria” (VDAM) project was conducted in north eastern and western Cambodia: Stung Treng; Battambang and Pailin provinces during 2016 to 2019. In total, VDAM reached 55 rural villages, 2,378 student participants and 43,502 audience members. Methods: This article presents the results of two stakeholder-led evaluation workshops in which participants collaboratively developed theories of change to better understand the potential and actual impact of arts and drama-based activities on malaria in these communities. The workshops had a particular focus on identifying areas for monitoring and evaluation so that impact can be measured. Workshop participants included village malaria workers, community leaders, professional and student drama performers, and representatives from the local health authorities and the national malaria control programme. Results: Five broad areas were identified as relevant for monitoring and evaluation: logistical and practical challenges; embeddedness and reach of engagement; health knowledge and confidence of young people; effectiveness of communications; impact on malaria. These areas align well with the monitoring and evaluation conducted to date and point to additional opportunities for data collection. Conclusions: The findings from these workshops will inform future engagement strategies, for example, we may engage a smaller number of young people but over a longer period and more in-depth.
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Affiliation(s)
- Mom Ean
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
| | - Nou Sanann
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand.,University Research Company, Phnom Penh, Cambodia
| | - James J Callery
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
| | - Christopher Pell
- 3Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
| | - Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, 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, 10400, 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, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.,The Ethox Centre, University of Oxford, Oxford, UK
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32
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Ean M, Sanann N, Callery JJ, Pell C, Peto TJ, Tripura R, Cheah PY. Theory of change: Drama and arts-based community engagement for malaria research and elimination in Cambodia. Wellcome Open Res 2021; 6:46. [PMID: 34041367 PMCID: PMC8127021 DOI: 10.12688/wellcomeopenres.16574.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2021] [Indexed: 01/24/2024] Open
Abstract
Background: Across the Greater Mekong Sub-region, malaria persists in isolated communities along international borders. Arts and drama have been used to reach to communities in Cambodia to engage them in malaria research, prevention and control. The "Village Drama Against Malaria" (VDAM) project was conducted in north eastern and western Cambodia: Stung Treng; Battambang and Pailin provinces during 2016 to 2019. In total, VDAM reached 55 rural villages, 2,378 student participants and 43,502 audience members. Methods: This article presents the results of two stakeholder-led evaluation workshops in which participants collaboratively developed theories of change to better understand the potential and actual impact of arts and drama-based activities on malaria in these communities. The workshops had a particular focus on identifying areas for monitoring and evaluation so that impact can be measured. Workshop participants included village malaria workers, community leaders, professional and student drama performers, and representatives from the local health authorities and the national malaria control programme. Results: Five broad areas were identified as relevant for monitoring and evaluation: logistical and practical challenges; embeddedness and reach of engagement; health knowledge and confidence of young people; effectiveness of communications; impact on malaria. These areas align well with the monitoring and evaluation conducted to date and point to additional opportunities for data collection. Conclusions: The findings from these workshops will inform future engagement strategies, for example, we may engage a smaller number of young people but over a longer period and more in-depth.
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Affiliation(s)
- Mom Ean
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
| | - Nou Sanann
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
- University Research Company, Phnom Penh, Cambodia
| | - James J. Callery
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
| | - Christopher Pell
- 3Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
| | - Thomas J. Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, 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, 10400, 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, 10400, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
- The Ethox Centre, University of Oxford, Oxford, UK
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Võ TC, Lê HG, Kang JM, Naw H, Fan CK, Trinh NTM, Quang HH, Na BK. Molecular surveillance of malaria in the Central Highlands, Vietnam. Parasitol Int 2021; 83:102374. [PMID: 33957296 DOI: 10.1016/j.parint.2021.102374] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 01/25/2023]
Abstract
Vietnam achieved outstanding success against malaria in the last few decades. The mortality and morbidity of malaria in Vietnam have decreased remarkably in recent years, but malaria is still a major public health concern in the country, particularly in the Central Highlands region. In this study, molecular analyses of malaria parasites in the Central Highlands were performed to understand the population structure and genetic diversity of the parasites circulating in the region. Plasmodium falciparum (68.7%) and P. vivax (27.4%) along with mixed infections with P. falciparum/P. vivax (3.9%) were detected in 230 blood samples from patients with malaria. Allele-specific nested-polymerase chain reaction (PCR) or PCR-restriction fragment length polymorphism (PCR-RFLP) analyses of pfmsp-1, pfama-1, pvcsp, and pvmsp-1 revealed complex genetic makeup in P. falciparum and P. vivax populations of Vietnam. Substantial multiplicity of infection (MOI) was also identified, suggesting significant genetic diversity and polymorphism of P. falciparum and P. vivax populations in the Central Highlands of Vietnam. These results provide fundamental insight into the current patterns of dispersion and genetic nature of malaria parasites as well as for the development of malaria elimination strategies in the endemic region.
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Affiliation(s)
- Tuấn Cường Võ
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea.
| | - Hương Giang Lê
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea.
| | - Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea.
| | - Haung Naw
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea.
| | - Chia-Kwung Fan
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine and Research Center of International Tropical Medicine, College of Medicine, Taipei Medical University, 250 Wu-Xing Street, Taipei, Taiwan.
| | - Nguyen Thi Minh Trinh
- Tropical Diseases Clinical and Treatment Research Department, Institute of Malariology, Parasitology, and Entomology Quy Nhon, MoH, 611B Nguyen Thai Hoc Street, Quy Nhon, Vietnam.
| | - Huynh Hong Quang
- Tropical Diseases Clinical and Treatment Research Department, Institute of Malariology, Parasitology, and Entomology Quy Nhon, MoH, 611B Nguyen Thai Hoc Street, Quy Nhon, Vietnam.
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea.
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Kyaw SS, Delmas G, Drake TL, Celhay O, Pan-Ngum W, Pukrittayakamee S, Lubell Y, Aguas RJ, Maude RJ, White LJ, Nosten F. Estimating the programmatic cost of targeted mass drug administration for malaria in Myanmar. BMC Public Health 2021; 21:826. [PMID: 33926399 PMCID: PMC8082869 DOI: 10.1186/s12889-021-10842-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 04/15/2021] [Indexed: 11/23/2022] Open
Abstract
Background Mass drug administration (MDA) has received growing interest to accelerate the elimination of multi-drug resistant malaria in the Greater Mekong Subregion. Targeted MDA, sometimes referred to as focal MDA, is the practice of delivering MDA to high incidence subpopulations only, rather than the entire population. The potential effectiveness of delivering targeted MDA was demonstrated in a recent intervention in Kayin State, Myanmar. Policymakers and funders need to know what resources are required if MDA, targeted or otherwise, is to be included in elimination packages beyond existing malaria interventions. This study aims to estimate the programmatic cost and the unit cost of targeted MDA in Kayin State, Myanmar. Methods We used financial data from a malaria elimination initiative, conducted in Kayin State, to estimate the programmatic costs of the targeted MDA component using a micro-costing approach. Three activities (community engagement, identification of villages for targeted MDA, and conducting mass treatment in target villages) were evaluated. We then estimated the programmatic costs of implementing targeted MDA to support P. falciparum malaria elimination in Kayin State. A costing tool was developed to aid future analyses. Results The cost of delivering targeted MDA within an integrated malaria elimination initiative in eastern Kayin State was approximately US$ 910,000. The cost per person reached, distributed among those in targeted and non-targeted villages, for the MDA component was US$ 2.5. Conclusion This cost analysis can assist policymakers in determining the resources required to clear malaria parasite reservoirs. The analysis demonstrated the value of using financial data from research activities to predict programmatic implementation costs of targeting MDA to different numbers of target villages. Supplementary Information The online version contains supplementary material available at 10.1186/s12889-021-10842-5.
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Affiliation(s)
- Shwe Sin Kyaw
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Gilles Delmas
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Mae Sot, Thailand
| | - Tom L Drake
- Department for International Development, London, UK
| | - Olivier Celhay
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wirichada Pan-Ngum
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sasithon Pukrittayakamee
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - 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 Clinical Medicine, University of Oxford, Oxford, UK
| | - Ricardo J 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 Clinical Medicine, University of Oxford, Oxford, UK
| | - Richard James 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.,Harvard TH Chan School of Public Health, Harvard University, Boston, USA
| | - Lisa J White
- Li Ka Shing Centre for Health Information and Discovery, Big Data Institute, University of Oxford, Oxford, UK
| | - Francois Nosten
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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Ngo TD, Canavati SE, Dung DV, Vo TH, Tran DT, Tran LK, Whedbee RJ, Milgotina EI, Kelly GC, Edgel KA, Martin NJ. Results from a malaria indicator survey highlight the importance of routine data capture in high-risk forest and farm transmission sites in Vietnam to tailor location-specific malaria elimination interventions. PLoS One 2021; 16:e0250045. [PMID: 33861798 PMCID: PMC8051764 DOI: 10.1371/journal.pone.0250045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 03/29/2021] [Indexed: 11/18/2022] Open
Abstract
In-line with the World Health Organization's (WHO) Global Technical Strategy for Malaria (2016-2030), Vietnam is striving to eliminate malaria by 2030. Targeting appropriate interventions in high-risk populations such as forest and forest-fringe communities is a critical component of malaria elimination efforts in Vietnam. In 2016, a household-level malaria indicator survey was conducted in Phu Yen Province, Vietnam with the aim of assessing the knowledge, behaviors and associated risks of malaria infection among priority mobile and migrant populations (MMPs) working and sleeping in forests and on farms. A total of 4211 people were included in the survey, comprised of 1074 heads of households and 3137 associated household members. Of the 1074 head-of-household respondents, 472 slept in a forest, 92 slept on a farm, 132 slept in both forests and farms, and 378 slept at their villages within the last 12 months. Age, literacy, and occupation were significantly different among those who slept in a forest versus on a farm. Of 301 respondents who answered questions about malaria risk factors at sleeping sites, 35% were somewhat aware of malaria prevention practices, but only 4% could recall at least four malaria prevention messages. Among the same group of 301 respondents, only 29% used nets and only 11% used treated nets. Ownership and use of nets among forest-goers was significantly lower than those who slept on a farm or in their village. Huts without walls were significantly prominent forest sleeping site locations (POR = 10.3; 95% CI 4.67-22.7). All respondents who slept in a forest requested standby malaria drugs and one-third of them self-treated without blood testing. Results from this study highlight the importance of capturing relevant location-specific data among priority populations such as remote forest and farm going mobile and migrant populations in Vietnam. Data regarding behavioral practices, knowledge, preventative measures, and intervention coverage at remote-area transmission sites must be routinely captured to effectively monitor progress and refine targeted intervention strategies accordingly.
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Affiliation(s)
- Thang Duc Ngo
- Department of Epidemiology, National Institute of Malariology, Parasitology and Entomology, Hanoi, Vietnam
| | - Sara E. Canavati
- Vysnova Partners, Inc., Landover, Maryland, United States of America
- Burnet Institute, Melbourne, Victoria, Australia
| | - Dang Viet Dung
- Department of Epidemiology, National Institute of Malariology, Parasitology and Entomology, Hanoi, Vietnam
| | - Thuan Huu Vo
- Vysnova Partners, Inc., Landover, Maryland, United States of America
| | - Duong Thanh Tran
- Department of Epidemiology, National Institute of Malariology, Parasitology and Entomology, Hanoi, Vietnam
| | - Long Khanh Tran
- Vysnova Partners, Inc., Landover, Maryland, United States of America
| | - Rosalie J. Whedbee
- Global Scientific Solutions for Health, Baltimore, Maryland, United States of America
| | | | - Gerard C. Kelly
- Vysnova Partners, Inc., Landover, Maryland, United States of America
- * E-mail:
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Abstract
Sarah Auburn and co-authors discuss the unique biology and epidemiology of P. vivax and current evidence on conventional and new approaches to surveillance.
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Affiliation(s)
- Sarah Auburn
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Qin Cheng
- Department of Drug Resistance and Diagnostics, Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
- The Australian Defence Force Malaria and Infectious Disease Institute Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Jutta Marfurt
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Ric N. Price
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
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Abstract
Relapses of Plasmodium vivax malaria are prevented by 8-aminoquinolines. If hypnozoites survive, then the subsequent blood stage infections in early relapses (< 2 months) are suppressed by the slowly eliminated anti-malarial drugs used to treat the blood stage infection (chloroquine, artemisinin combination treatments), but they are not usually eliminated. The 8-aminoquinolines have significant blood stage activity which contributes to therapeutic responses. The latent interval from primary infection to early relapse depends on the number of activatable hypnozoites, the dose of anti-malarial, its pharmacokinetic properties, the level of resistance (minimum inhibitory concentration) and immunity. The dose-response relationship for radical curative efficacy of primaquine and tafenoquine is steep over the total dose range from 1.5 to 5 mg base/kg which may explain the poor efficacy of tafenoquine at the currently recommended dose.
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Affiliation(s)
- Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.
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Zainabadi K. Ultrasensitive Diagnostics for Low-Density Asymptomatic Plasmodium falciparum Infections in Low-Transmission Settings. J Clin Microbiol 2021; 59:e01508-20. [PMID: 33148707 DOI: 10.1128/JCM.01508-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The emergence of multidrug-resistant Plasmodium falciparum malaria in Southeast Asia (SEA) has accelerated regional malaria elimination efforts. Most malaria in this and other low-transmission settings exists in asymptomatic individuals, which conventional diagnostic tests lack the sensitivity to detect. This has led to the development of new ultrasensitive diagnostics that are capable of detecting these low-parasitemia infections. This review summarizes the current status of ultrasensitive technologies, including PCR and loop-mediated isothermal amplification (LAMP)-based methods, as well as a newly developed ultrasensitive rapid diagnostic test (uRDT). The sensitivity, specificity, and field performance of these platforms will be examined, as well as their suitability for use in resource-limited settings to aid in malaria elimination efforts. uRDTs, with their improved sensitivity, are now able to detect approximately half of asymptomatic infections, providing a useful point-of-contact tool for malaria surveillance. The increased sensitivity and high-throughput nature of PCR-based tests make them ideal for screening large populations in places where laboratory capacity exists, and the recent commercialization of malaria LAMP kits should facilitate their adoption as a public health tool in places where such infrastructure is lacking. Finally, recent advances with dried blood spots may enable utilization of the extensive laboratory infrastructure of higher-income countries to assist with molecular surveillance in support of malaria elimination. If malaria is to be eliminated in SEA and other low-endemicity regions, then ultrasensitive diagnostics will likely play a key role in identifying and clearing the vast asymptomatic pool of infections that are common to these regions.
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Fink J, Jones PD. High Prevalence of Low-Level Parasitemia With Plasmodium vivax in Makira-Ulawa Province Presents a Challenge for the Diagnosis and Eradication of Malaria in Solomon Islands. Ochsner J 2021; 21:76-80. [PMID: 33828428 DOI: 10.31486/toj.20.0023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background: Malaria remains endemic in Solomon Islands, but data on malaria in the provinces of Solomon Islands are limited. This study from Makira-Ulawa Province aimed to identify the most prevalent strain of malaria and assess if the available rapid diagnostic test (RDT) was effective in Kirakira Hospital. Methods: Forty-five patients who presented to Kirakira Hospital with symptoms of fever had a positive malaria parasite smear during a 4-week period in 2017. The parasite count for each smear was calculated. Simultaneous testing using the CareStart Malaria HRP2/pLDH (Pf/pan) Combo RDT was conducted. The data for all malaria parasite smears performed in Makira-Ulawa Province in 2016 were collated for comparison. Results: All 45 patients diagnosed with malaria in a 4-week period in 2017 were positive for Plasmodium vivax. The median parasite load was 280 parasites per μL (range, 160 to 640 parasites per μL). None of the 45 CareStart RDTs performed was positive. In 2016, 5,505 of 17,195 patients (32.0%) screened had malaria parasites detected on a malaria parasite smear. P vivax was detected in 5,212 (94.7%) and Plasmodium falciparum in 285 (5.2%) of patients with malaria. Conclusion:P vivax is the predominant strain of malaria present in Makira-Ulawa Province. RDTs were not helpful in the diagnosis of malaria at Kirakira Hospital. The parasite load detected in the 45 patients diagnosed with malaria in this study was low. A focus on attempting to eradicate P vivax in the community through improved compliance with treatment protocols is suggested as a possible way forward to best manage malaria in Makira-Ulawa Province.
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40
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Acquah FK, Donu D, Obboh EK, Bredu D, Mawuli B, Amponsah JA, Quartey J, Amoah LE. Diagnostic performance of an ultrasensitive HRP2-based malaria rapid diagnostic test kit used in surveys of afebrile people living in Southern Ghana. Malar J 2021; 20:125. [PMID: 33653356 PMCID: PMC7927401 DOI: 10.1186/s12936-021-03665-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
Background The Alere™ Malaria Ag P.f Ultra-sensitive RDT (UsmRDT) kit is an HRP2-based malaria rapid diagnostic test (RDT) with enhanced sensitivity relative to the SD Bioline Malaria Ag P.f RDT (mRDT) kit. However, the diagnostic performance of the UsmRDT kit has not been evaluated in Ghana. Methods A total of 740 afebrile participants aged between 3 and 88 years old were recruited from the Central and Greater Accra Regions of Ghana during the off-peak malaria season. Axillary body temperature was measured, and a volume of 1 ml venous blood was drawn from each participant. Prior to separating the blood into plasma and packed cell pellets via centrifugation, the blood was spotted onto one UsmRDT and one mRDT kit and also used to prepare thick and thin blood smears as well as filter paper blood spots. Plasmodium falciparum specific polymerase chain reaction (PCR) was performed on gDNA extracted from 100 µl of the whole blood. Results The overall positivity rate for microscopy, PCR, UsmRDT and mRDT kit were 20.4%, 40.8%, 31.3% and 30.8%, respectively. Overall, the UsmRDT identified 9.3% (28/302) more PCR positive samples than the mRDT kits. All samples that were negative by the UsmRDT kit were also negative by the mRDT kit. Overall, the sensitivity and specificity of the UsmRDT was 73% (221/302) and 89% (388/436), respectively, while that for the mRDT kit was 58% and 90%, respectively. Conclusion Although the UsmRDT kit was not as sensitive as PCR at detecting asymptomatic P. falciparum carriage, it correctly identified P. falciparum in 9.3% of the study participants that were not captured by the mRDT kit. In malaria endemic settings, the UsmRDT would provide an added advantage by identifying more asymptomatic P. falciparum carriers than the mRDT kit for targeted treatment interventions.
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Affiliation(s)
- Festus K Acquah
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana.,West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Dickson Donu
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Evans K Obboh
- School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Dorcas Bredu
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Bernice Mawuli
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Jones A Amponsah
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Joseph Quartey
- Parasitology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Linda E Amoah
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana. .,West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana.
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Sallah K, Giorgi R, Ba EH, Piarroux M, Piarroux R, Cisse B, Gaudart J. Targeting Malaria Hotspots to Reduce Transmission Incidence in Senegal. Int J Environ Res Public Health 2020; 18:E76. [PMID: 33374228 DOI: 10.3390/ijerph18010076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 11/16/2022]
Abstract
In central Senegal, malaria incidence declined in response to scaling-up of control measures from 2000 to 2010 and has since remained stable, making elimination unlikely in the short term. Additional control measures are needed to reduce transmission. We simulated chemoprophylaxis interventions targeting malaria hotspots using a metapopulation mathematical model, based on a differential-equation framework and incorporating human mobility. The model was fitted to weekly malaria incidence from 45 villages. Three approaches for selecting intervention targets were compared: (a) villages with malaria cases during the low transmission season of the previous year; (b) villages with highest incidence during the high transmission season of the previous year; (c) villages with highest connectivity with adjacent populations. Our results showed that intervention strategies targeting hotspots would be effective in reducing malaria incidence in both targeted and untargeted areas. Regardless of the intervention strategy used, pre-elimination (1-5 cases per 1000 per year) would not be reached without simultaneously increasing vector control by more than 10%. A cornerstone of malaria control and elimination is the effective targeting of strategic locations. Mathematical tools help to identify those locations and estimate the impact in silico.
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Hoffman‐Hall A, Puett R, Silva JA, Chen D, Baer A, Han KT, Han ZY, Thi A, Htay T, Thein ZW, Aung PP, Plowe CV, Nyunt MM, Loboda TV. Malaria Exposure in Ann Township, Myanmar, as a Function of Land Cover and Land Use: Combining Satellite Earth Observations and Field Surveys. Geohealth 2020; 4:e2020GH000299. [PMID: 33364532 PMCID: PMC7752622 DOI: 10.1029/2020gh000299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/07/2020] [Accepted: 10/22/2020] [Indexed: 06/12/2023]
Abstract
Despite progress toward malaria elimination in the Greater Mekong Subregion, challenges remain owing to the emergence of drug resistance and the persistence of focal transmission reservoirs. Malaria transmission foci in Myanmar are heterogeneous and complex, and many remaining infections are clinically silent, rendering them invisible to routine monitoring. The goal of this research is to define criteria for easy-to-implement methodologies, not reliant on routine monitoring, that can increase the efficiency of targeted malaria elimination strategies. Studies have shown relationships between malaria risk and land cover and land use (LCLU), which can be mapped using remote sensing methodologies. Here we aim to explain malaria risk as a function of LCLU for five rural villages in Myanmar's Rakhine State. Malaria prevalence and incidence data were analyzed through logistic regression with a land use survey of ~1,000 participants and a 30-m land cover map. Malaria prevalence per village ranged from 5% to 20% with the overwhelming majority of cases being subclinical. Villages with high forest cover were associated with increased risk of malaria, even for villagers who did not report visits to forests. Villagers living near croplands experienced decreased malaria risk unless they were directly engaged in farm work. Finally, land cover change (specifically, natural forest loss) appeared to be a substantial contributor to malaria risk in the region, although this was not confirmed through sensitivity analyses. Overall, this study demonstrates that remotely sensed data contextualized with field survey data can be used to inform critical targeting strategies in support of malaria elimination.
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Affiliation(s)
| | - Robin Puett
- School of Public Health, Maryland Institute for Applied Environmental HealthUniversity of MarylandCollege ParkMDUSA
| | - Julie A. Silva
- Department of Geographical SciencesUniversity of MarylandCollege ParkMDUSA
| | - Dong Chen
- Department of Geographical SciencesUniversity of MarylandCollege ParkMDUSA
| | - Allison Baer
- Department of Geographical SciencesUniversity of MarylandCollege ParkMDUSA
| | - Kay Thwe Han
- Department of Medical ResearchMyanmar Ministry of Health and SportsYangonMyanmar
| | - Zay Yar Han
- Department of Medical ResearchMyanmar Ministry of Health and SportsYangonMyanmar
| | - Aung Thi
- National Malaria Control ProgrammeMyanmar Ministry of Health and SportsNaypyitawMyanmar
| | - Thura Htay
- Duke Global Health Institute Myanmar ProgramYangonMyanmar
| | - Zaw Win Thein
- Duke Global Health Institute Myanmar ProgramYangonMyanmar
| | - Poe Poe Aung
- Duke Global Health Institute Myanmar ProgramYangonMyanmar
| | | | | | - Tatiana V. Loboda
- Department of Geographical SciencesUniversity of MarylandCollege ParkMDUSA
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Imwong M, Dhorda M, Myo Tun K, Thu AM, Phyo AP, Proux S, Suwannasin K, Kunasol C, Srisutham S, Duanguppama J, Vongpromek R, Promnarate C, Saejeng A, Khantikul N, Sugaram R, Thanapongpichat S, Sawangjaroen N, Sutawong K, Han KT, Htut Y, Linn K, Win AA, Hlaing TM, van der Pluijm RW, Mayxay M, Pongvongsa T, Phommasone K, Tripura R, Peto TJ, von Seidlein L, Nguon C, Lek D, Chan XHS, Rekol H, Leang R, Huch C, Kwiatkowski DP, Miotto O, Ashley EA, Kyaw MP, Pukrittayakamee S, Day NPJ, Dondorp AM, Smithuis FM, Nosten FH, White NJ. Molecular epidemiology of resistance to antimalarial drugs in the Greater Mekong subregion: an observational study. Lancet Infect Dis 2020; 20:1470-1480. [PMID: 32679084 PMCID: PMC7689289 DOI: 10.1016/s1473-3099(20)30228-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/19/2020] [Accepted: 03/16/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND The Greater Mekong subregion is a recurrent source of antimalarial drug resistance in Plasmodium falciparum malaria. This study aimed to characterise the extent and spread of resistance across this entire region between 2007 and 2018. METHODS P falciparum isolates from Myanmar, Thailand, Laos, and Cambodia were obtained from clinical trials and epidemiological studies done between Jan 1, 2007, and Dec 31, 2018, and were genotyped for molecular markers (pfkelch, pfcrt, pfplasmepsin2, and pfmdr1) of antimalarial drug resistance. Genetic relatedness was assessed using microsatellite and single nucleotide polymorphism typing of flanking sequences around target genes. FINDINGS 10 632 isolates were genotyped. A single long pfkelch Cys580Tyr haplotype (from -50 kb to +31·5 kb) conferring artemisinin resistance (PfPailin) now dominates across the eastern Greater Mekong subregion. Piperaquine resistance associated with pfplasmepsin2 gene amplification and mutations in pfcrt downstream of the Lys76Thr chloroquine resistance locus has also developed. On the Thailand-Myanmar border a different pfkelch Cys580Tyr lineage rose to high frequencies before it was eliminated. Elsewhere in Myanmar the Cys580Tyr allele remains widespread at low allele frequencies. Meanwhile a single artemisinin-resistant pfkelch Phe446Ile haplotype has spread across Myanmar. Despite intense use of dihydroartemisinin-piperaquine in Kayin state, eastern Myanmar, both in treatment and mass drug administrations, no selection of piperaquine resistance markers was observed. pfmdr1 amplification, a marker of resistance to mefloquine, remains at low prevalence across the entire region. INTERPRETATION Artemisinin resistance in P falciparum is now prevalent across the Greater Mekong subregion. In the eastern Greater Mekong subregion a multidrug resistant P falciparum lineage (PfPailin) dominates. In Myanmar a long pfkelch Phe446Ile haplotype has spread widely but, by contrast with the eastern Greater Mekong subregion, there is no indication of artemisinin combination therapy (ACT) partner drug resistance from genotyping known markers, and no evidence of spread of ACT resistant P falciparum from the east to the west. There is still a window of opportunity to prevent global spread of ACT resistance. FUNDING Thailand Science Research and Innovation, Initiative 5%, Expertise France, Wellcome Trust.
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Affiliation(s)
- Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Mehul Dhorda
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Worldwide Antimalarial Resistance Network, Bangkok, Thailand
| | - Kyaw Myo Tun
- Department of Preventive and Social Medicine, Defence Services Medical Academy, Yangon, Myanmar
| | - Aung Myint Thu
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Aung Pyae Phyo
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
| | - Stephane Proux
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, 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
| | - Suttipat Srisutham
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jureeporn Duanguppama
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Aungkana Saejeng
- Bureau of Vector-borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | | | - Rungniran Sugaram
- Bureau of Vector-borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | | | - Nongyao Sawangjaroen
- Department of Microbiology, Faculty of Science, Prince of Songkla University, Songkhla, Thailand
| | - Kreepol Sutawong
- Buntharik Hospital, Amphoe Buntharik, Ubon Ratchathani, Thailand
| | - Kay Thwe Han
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Ye Htut
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Khin Linn
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Aye Aye Win
- Department of Tropical and Infectious Diseases, University of Medicine 1, Yangon, Myanmar
| | - Tin M Hlaing
- Defence Services Medical Research Centre, Naypyitaw, Myanmar
| | - 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, UK
| | - Mayfong Mayxay
- Institute of Research and Education Development, University of Health Sciences, Ministry of Health, Vientiane, Laos; Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos
| | - Tiengkham Pongvongsa
- Savannakhet Provincial Health Department, Phonsavangnuea village, Kaysone-Phomvihan district, Savannakhet, Laos
| | - Koukeo Phommasone
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos
| | - 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
| | - 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
| | - 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
| | - Chea Nguon
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Dysoley Lek
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Xin Hui S 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, UK
| | - Huy Rekol
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Rithea Leang
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Cheah Huch
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Dominic P Kwiatkowski
- Wellcome Sanger Institute, Hinxton, UK; Medical Research Council Centre for Genomics and Global Health, Big Data Institute, University of Oxford, Oxford, UK
| | - Olivo Miotto
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Wellcome Sanger Institute, Hinxton, UK; Medical Research Council Centre for Genomics and Global Health, Big Data Institute, University of Oxford, Oxford, UK
| | - Elizabeth A Ashley
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos
| | - Myat Phone Kyaw
- Department of Medical Research, Myanmar Health Network Organization, Yangon, Myanmar
| | - 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; The Royal Society of Thailand, Dusit, Bangkok, Thailand
| | - 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, 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, University of Oxford, Oxford, UK
| | - Frank M Smithuis
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Medical Action Myanmar, Yangon, Myanmar
| | - Francois 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
| | - 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, UK
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Sandfort M, Vantaux A, Kim S, Obadia T, Pepey A, Gardais S, Khim N, Lek D, White M, Robinson LJ, Witkowski B, Mueller I. Forest malaria in Cambodia: the occupational and spatial clustering of Plasmodium vivax and Plasmodium falciparum infection risk in a cross-sectional survey in Mondulkiri province, Cambodia. Malar J 2020; 19:413. [PMID: 33213471 PMCID: PMC7678315 DOI: 10.1186/s12936-020-03482-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/04/2020] [Indexed: 02/24/2023] Open
Abstract
Background After a marked reduction in malaria burden in Cambodia over the last decades, case numbers increased again in 2017–2018. In light of the national goal of malaria elimination by 2025, remaining pockets of high risk need to be well defined and strategies well-tailored to identify and target the persisting burden cost-effectively. This study presents species-specific prevalence estimates and risk stratification for a remote area in Cambodia. Methods A cross-sectional survey was conducted in 17 villages in the high-incidence province Mondulkiri in the dry season (December 2017 to April 2018). 4200 randomly selected participants (2–80 years old) were tested for Plasmodium infection by PCR. Risk of infection was associated with questionnaire-derived covariates and spatially stratified based on household GPS coordinates. Results The prevalence of PCR-detectable Plasmodium infection was 8.3% (349/4200) and was more than twice as high for Plasmodium vivax (6.4%, 268) than for Plasmodium falciparum (3.0%, 125, p < 0.001). 97.8% (262/268) of P. vivax and 92.8% (116/125, p < 0.05) of P. falciparum infections were neither accompanied by symptoms at the time of the interview nor detected by microscopy or RDT. Recent travels to forest sites (aOR 2.17, p < 0.01) and forest work (aOR 2.88, p < 0.001) were particularly strong risk factors and risk profiles for both species were similar. Large village-level differences in prevalence of Plasmodium infection were observed, ranging from 0.6% outside the forest to 40.4% inside. Residing in villages at the forest fringe or inside the forest compared to outside was associated with risk of infection (aOR 2.14 and 12.47, p < 0.001). Villages inside the forest formed spatial hotspots of infection despite adjustment for the other risk factors. Conclusions Persisting pockets of high malaria risk were detected in forested areas and in sub-populations engaging in forest-related activities. High levels of asymptomatic infections suggest the need of better case detection plans and the predominance of P. vivax the implementation of radical cure. In villages inside the forest, within-village exposure was indicated in addition to risk due to forest activities. Village-level stratification of targeted interventions based on forest proximity could render the elimination efforts more cost-effective and successful.
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Affiliation(s)
- Mirco Sandfort
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France. .,Sorbonne Université, Collège doctoral, Paris, France.
| | - Amélie Vantaux
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Saorin Kim
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Thomas Obadia
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France.,Hub de Bioinformatique et Biostatistique, Département Biologie Computationnelle, Institut Pasteur, USR 3756 CNRS, Paris, France
| | - Anaïs Pepey
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Soazic Gardais
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France
| | - Nimol Khim
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Dysoley Lek
- National Centre for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia.,School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Michael White
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France.,Population Health & Immunity, Walter and Eliza Hall Institute, Melbourne, Australia
| | - Leanne J Robinson
- Population Health & Immunity, Walter and Eliza Hall Institute, Melbourne, Australia.,University of Melbourne, Melbourne, Australia.,Burnet Institute, Melbourne, Australia
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Ivo Mueller
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France.,Population Health & Immunity, Walter and Eliza Hall Institute, Melbourne, Australia.,University of Melbourne, Melbourne, Australia
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45
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Dhorda M, Ba EH, Kevin Baird J, Barnwell J, Bell D, Carter JY, Dondorp A, Ekawati L, Gatton M, González I, Guérin PJ, Incardona S, Lilley K, Menard D, Nosten F, Obare P, Ogutu B, Olliaro PL, Price RN, Proux S, Ramsay AR, Reeder JC, Silamut K, Sokhna C. Towards harmonization of microscopy methods for malaria clinical research studies. Malar J 2020; 19:324. [PMID: 32887612 PMCID: PMC7471592 DOI: 10.1186/s12936-020-03352-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 07/28/2020] [Indexed: 01/13/2023] Open
Abstract
Microscopy performed on stained films of peripheral blood for detection, identification and quantification of malaria parasites is an essential reference standard for clinical trials of drugs, vaccines and diagnostic tests for malaria. The value of data from such research is greatly enhanced if this reference standard is consistent across time and geography. Adherence to common standards and practices is a prerequisite to achieve this. The rationale for proposed research standards and procedures for the preparation, staining and microscopic examination of blood films for malaria parasites is presented here with the aim of improving the consistency and reliability of malaria microscopy performed in such studies. These standards constitute the core of a quality management system for clinical research studies employing microscopy as a reference standard. They can be used as the basis for the design of training and proficiency testing programmes as well as for procedures and quality assurance of malaria microscopy in clinical research.
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Affiliation(s)
- Mehul Dhorda
- WorldWide Antimalarial Resistance Network, 60th Anniversary Chalermprakhiat Building 3rd Floor, 420/6 Ratchawithi Road, Ratchathewi, Bangkok, 10400 Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - El Hadji Ba
- UMR 257 IRD VITROME, Campus IRD-UCAD, Dakar, Senegal
| | - J. Kevin Baird
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.418754.b0000 0004 1795 0993Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia
| | - John Barnwell
- grid.416738.f0000 0001 2163 0069US Centers for Disease Control and Prevention, Atlanta, USA
| | - David Bell
- Independent consultant, Issaquah, WA USA
| | - Jane Y. Carter
- grid.413353.30000 0004 0621 4210Amref Health Africa Headquarters, Nairobi, Kenya
| | - Arjen Dondorp
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lenny Ekawati
- grid.418754.b0000 0004 1795 0993Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia
| | - Michelle Gatton
- grid.1024.70000000089150953Queensland University of Technology, Brisbane, Australia
| | - Iveth González
- grid.475489.30000 0001 2364 5600Terre des Hommes Foundation, Geneva, Switzerland
| | - Philippe J. Guérin
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.499581.8WorldWide Antimalarial Resistance Network, Oxford, UK
| | | | - Ken Lilley
- Australian Defence Force Malaria and Infectious Disease Institute, Enoggera, Australia
| | - Didier Menard
- grid.418537.cInstitut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - François Nosten
- grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.10223.320000 0004 1937 0490Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Peter Obare
- grid.33058.3d0000 0001 0155 5938Kenya Medical Research Institute, Kisumu, Kenya
| | - Bernhards Ogutu
- grid.33058.3d0000 0001 0155 5938Kenya Medical Research Institute, Kisumu, Kenya
| | - Piero L. Olliaro
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Ric N. Price
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.499581.8WorldWide Antimalarial Resistance Network, Oxford, UK ,grid.1043.60000 0001 2157 559XGlobal Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT Australia
| | - Stéphane Proux
- grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.10223.320000 0004 1937 0490Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Andrew R. Ramsay
- grid.11914.3c0000 0001 0721 1626School of Medicine, University of St Andrews, St Andrews, UK
| | - John C. Reeder
- Special Programme for Research and Training in Tropical Diseases (TDR), a Co-sponsored Programme of UNICEF, UNDP, the World Bank and WHO, Geneva, Switzerland
| | - Kamolrat Silamut
- grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Cheikh Sokhna
- UMR 257 IRD VITROME, Campus IRD-UCAD, Dakar, Senegal
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Gruenberg M, Moniz CA, Hofmann NE, Koepfli C, Robinson LJ, Nate E, Monteiro WM, de Melo GC, Kuehn A, Siqueira AM, Nguitragool W, Bassat Q, Lacerda M, Sattabongkot J, Mueller I, Felger I. Utility of ultra-sensitive qPCR to detect Plasmodium falciparum and Plasmodium vivax infections under different transmission intensities. Malar J 2020; 19:319. [PMID: 32883308 PMCID: PMC7469345 DOI: 10.1186/s12936-020-03374-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 08/13/2020] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND The use of molecular diagnostics has revealed an unexpectedly large number of asymptomatic low-density malaria infections in many malaria endemic areas. This study compared the gains in parasite prevalence obtained by the use of ultra-sensitive (us)-qPCR as compared to standard qPCR in cross-sectional surveys conducted in Thailand, Brazil and Papua New Guinea (PNG). The compared assays differed in the copy number of qPCR targets in the parasite genome. METHODS Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) parasites were quantified by qPCR amplifying the low-copy Pf_ and Pv_18S rRNA genes or the multi-copy targets Pf_varATS and Pv_mtCOX1. Cross-sectional surveys at the three study sites included 2252 participants of all ages and represented different transmission intensities. RESULTS In the two low-transmission areas, P. falciparum positivity was 1.3% (10/773) (Thailand) and 0.8% (5/651) (Brazil) using standard Pf_18S rRNA qPCR. In these two countries, P. falciparum positivity by Pf_varATS us-qPCR increased to 1.9% (15/773) and 1.7% (11/651). In PNG, an area with moderate transmission intensity, P. falciparum positivity significantly increased from 8.6% (71/828) by standard qPCR to 12.2% (101/828) by us-qPCR. The proportions of P. falciparum infections not detected by standard qPCR were 33%, 55% and 30% in Thailand, Brazil and PNG. Plasmodium vivax was the predominating species in Thailand and Brazil, with 3.9% (30/773) and 4.9% (32/651) positivity by Pv_18S rRNA qPCR. In PNG, P. vivax positivity was similar to P. falciparum, at 8.0% (66/828). Use of Pv_mtCOX1 us-qPCR led to a significant increase in positivity to 5.1% (39/773), 6.4% (42/651) and 11.5% (95/828) in Thailand, Brazil, and PNG. The proportions of P. vivax infections missed by standard qPCR were similar at all three sites, with 23%, 24% and 31% in Thailand, Brazil and PNG. CONCLUSION The proportional gains in the detection of P. falciparum and P. vivax infections by ultra-sensitive diagnostic assays were substantial at all three study sites. Thus, us-qPCR yields more precise prevalence estimates for both P. falciparum and P. vivax at all studied levels of endemicity and represents a significant diagnostic improvement. Improving sensitivity in P. vivax surveillance by us-qPCR is of particular benefit, because the additionally detected P. vivax infections signal the potential presence of hypnozoites and subsequent risk of relapse and further transmission.
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Affiliation(s)
- Maria Gruenberg
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Clara Antunes Moniz
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Natalie E Hofmann
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Cristian Koepfli
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Leanne J Robinson
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.,Burnet Institute, Melbourne, Australia
| | - Elma Nate
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | | | | | - Andrea Kuehn
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil.,ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Andre M Siqueira
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil.,Instituto Nacional de Infectologia Evandro Chagas, Fiocruz, Rio de Janeiro, Brazil
| | - Wang Nguitragool
- Department of Molecular Tropical Medicine & Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Quique Bassat
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Marcus Lacerda
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil.,Universidade Do Estado Do Amazonas, Manaus, Brazil
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ivo Mueller
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Australia.,Malaria Parasite & Hosts Unit, Institut Pasteur, Paris, France
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
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47
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Thompson TA, Touré MB, Sanogo D, Shaffer JG, Doumbia SO, Krogstad DJ. Template copy number and the sensitivity of quantitative PCR for Plasmodium falciparum in asymptomatic individuals. Malar J 2020; 19:295. [PMID: 32811534 PMCID: PMC7436962 DOI: 10.1186/s12936-020-03365-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 08/10/2020] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND The identification of asymptomatic individuals with Plasmodium falciparum infection is difficult because they do not seek medical treatment and often have too few asexual parasites detectable using microscopy or rapid diagnostic tests (≤ 200 parasites per μl). Quantitative PCR (qPCR) may provide greater sensitivity and permits estimation of the initial template DNA concentration. This study examined the hypothesis that qPCR assays using templates with higher copy numbers may be more sensitive for P. falciparum than assays based on templates with lower copy numbers. METHODS To test this hypothesis, ten qPCR assays for DNA sequences with template copy numbers from 1 to 160 were compared using parasite DNA standards (n = 2) and smear-positive filter paper blots from asymptomatic smear-positive subjects (n = 96). RESULTS Based on the testing of P. falciparum parasite DNA standards and filter paper blots, cycle threshold values decreased as the concentrations of template DNA and template copy numbers increased (p < 0.001). Likewise, the analytical and clinical sensitivities of qPCR assays for P. falciparum DNA (based on DNA standards and filter paper blots, respectively) increased with template copy number. Despite the gains in clinical sensitivity from increased template copy numbers, qPCR assays failed to detect more than half of the filter paper blots with low parasite densities (≤ 200 asexual parasites per μl). CONCLUSIONS These results confirm the hypothesis that the sensitivity of qPCR for P. falciparum in the blood of individuals with asymptomatic infection increases with template copy number. However, because even the most sensitive qPCR assays (with template copy numbers from 32 to 160) detected fewer than 50% of infections with ≤ 200 asexual parasites per μl, the sensitivity of qPCR must be increased further to identify all smear-positive, asymptomatic individuals in order to interrupt transmission.
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Affiliation(s)
- Trevor A Thompson
- West African International Center of Excellence for Malaria Research, Bamako, Mali.
- Tulane School of Public Health and Tropical Medicine, 1430 Tulane Avenue, #8317, J.B. Johnston Building, Room 510, New Orleans, LA, 70112-2699, USA.
| | - Mahamoudou B Touré
- West African International Center of Excellence for Malaria Research, Bamako, Mali
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Daouda Sanogo
- West African International Center of Excellence for Malaria Research, Bamako, Mali
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Jeffrey G Shaffer
- West African International Center of Excellence for Malaria Research, Bamako, Mali.
- Tulane School of Public Health and Tropical Medicine, 1430 Tulane Avenue, #8317, J.B. Johnston Building, Room 510, New Orleans, LA, 70112-2699, USA.
| | - Seydou O Doumbia
- West African International Center of Excellence for Malaria Research, Bamako, Mali
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Donald J Krogstad
- West African International Center of Excellence for Malaria Research, Bamako, Mali.
- Tulane School of Public Health and Tropical Medicine, 1430 Tulane Avenue, #8317, J.B. Johnston Building, Room 510, New Orleans, LA, 70112-2699, USA.
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48
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Kotepui M, Kotepui KU, De Jesus Milanez G, Masangkay FR. Summary of discordant results between rapid diagnosis tests, microscopy, and polymerase chain reaction for detecting Plasmodium mixed infection: a systematic review and meta-analysis. Sci Rep 2020; 10:12765. [PMID: 32728145 PMCID: PMC7392751 DOI: 10.1038/s41598-020-69647-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/15/2020] [Indexed: 01/28/2023] Open
Abstract
Malaria rapid diagnostic tests (RDTs) are widely used to detect malaria parasites among patients who suspected malaria infections in malaria-endemic areas where microscopy is unavailable. Nevertheless, little is known about the performance of RDTs in detecting Plasmodium mixed infections. The present study aimed to evaluate the discordant results between RDTs and microscopy/polymerase chain reaction (PCR) in detecting Plasmodium mixed infections. The PubMed (MEDLINE), Web of Science, and Scopus databases were systematically reviewed to identify related studies that reported the performance of RDTs in detecting Plasmodium mixed infections. Studies were grouped according to the different RDT types including RDT type 2 (pf-HRP2/pan-aldolase), RDT type 3 (pf-HRP2/pan-pLDH), RDT type 4 (Pf-LDH/pan-pLDH), RDT type 5 (Pf/Pv-pLDH), and RDT type 6 (pf-HRP2/Pv-pLDH) for subgroup analysis. The estimates of the different proportions in each analysis group that were visually summarized in a forest plot showed the odds ratio (OR) and 95% confidence interval (CI). Plots were drawn using RevMan (version 5.3; Cochrane Community). Twenty-eight studies were included in the present study. Overall, the meta-analysis showed that RDTs could detect a significantly higher proportion of Plasmodium mixed infections than microscopy (p = 0.0007, OR = 3.33, 95% CI 1.66-6.68). Subgroup analysis demonstrated that only RDTs targeting Pf-specific histidine-rich protein 2 (HRP2)/pan-specific lactate dehydrogenase (LDH) could detect a significantly higher proportion of Plasmodium mixed infections than microscopy (p = 0.004, OR = 8.46, 95% CI 2.75-26.1). The subgroup analysis between RDTs and PCR methods demonstrated that RDTs targeting Pf-specific HRP2/Pv-specific LDH could detect a significantly lower proportion of Plasmodium mixed infections than PCR methods (p = 0.0005, OR = 0.42, 95% CI 0.26-0.68). This is the first study to summarize the discordant results between RDTs and microscopy/PCR in detecting Plasmodium mixed infections. Malaria RDTs targeting Pf-HRP2/pan-pLDH could detect a higher proportion of Plasmodium mixed infections than microscopy, while RDTs targeting Pf-HRP2/Pv-specific LDH could detect a lower proportion of Plasmodium mixed infections than PCR methods. The results of this study will support the selection and careful interpretations of RDTs for a better diagnosis of Plasmodium mixed-species infections and appropriate treatment of malaria patients in endemic and non-endemic settings.
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Affiliation(s)
- Manas Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand.
| | - Kwuntida Uthaisar Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | - Giovanni De Jesus Milanez
- Department of Medical Technology, Institute of Arts and Sciences, Far Eastern University-Manila, Manila, Philippines
| | - Frederick Ramirez Masangkay
- Department of Medical Technology, Institute of Arts and Sciences, Far Eastern University-Manila, Manila, Philippines
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49
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Shimizu S, Chotirat S, Dokkulab N, Hongchad I, Khowsroy K, Kiattibutr K, Maneechai N, Manopwisedjaroen K, Petchvijit P, Phumchuea K, Rachaphaew N, Sripoorote P, Suansomjit C, Thongyod W, Khamsiriwatchara A, Lawpoolsri S, Hanboonkunupakarn B, Sattabongkot J, Nguitragool W. Malaria cross-sectional surveys identified asymptomatic infections of Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi in Surat Thani, a southern province of Thailand. Int J Infect Dis 2020; 96:445-451. [PMID: 32407902 DOI: 10.1016/j.ijid.2020.05.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/06/2020] [Accepted: 05/06/2020] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVES Malaria cross-sectional surveys are rarely conducted in very low transmission settings. This study aimed to determine the prevalence and risk factors of Plasmodium infection in a near-elimination setting in southern Thailand. METHODS Two cross-sectional surveys were conducted in areas of active transmission in the Surat Thani province of Thailand in January and May 2019. PCR was used to detect Plasmodium infection. RESULTS The prevalence of Plasmodium blood infection was 0.45% and 0.61% in January and May 2019, respectively. The major parasite species was Plasmodium falciparum in January and Plasmodium vivax in May. Unexpectedly, Plasmodium knowlesi infections were also detected. Most infections, including those of Plasmodium knowlesi, were asymptomatic. Being male and staying outdoors at night-time were the only significant identified risk factors. Of people infected in January 28.0% were positive in May for the same parasite species, suggesting persistent asymptomatic infections. CONCLUSIONS Despite the very low incidence rate in Surat Thani, most malaria infections were asymptomatic. Outdoor mosquito biting at night-time is likely an important mode of malaria transmission. Unexpectedly, asymptomatic Plasmodium knowlesi infection was found, confirming previous reports of such infection in mainland Southeast Asia.
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Affiliation(s)
- Shoichi Shimizu
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sadudee Chotirat
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nichakan Dokkulab
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Isarachai Hongchad
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kessuda Khowsroy
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kirakorn Kiattibutr
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nongnuj Maneechai
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Pattamaporn Petchvijit
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kanit Phumchuea
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nattawan Rachaphaew
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Piyarat Sripoorote
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chayanut Suansomjit
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Waraporn Thongyod
- Mahidol Vivax Research Unit, 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
| | - Saranath Lawpoolsri
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Borimas Hanboonkunupakarn
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wang Nguitragool
- Department of Molecular Tropical Medicine & Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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50
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Raman J, Gast L, Balawanth R, Tessema S, Brooke B, Maharaj R, Munhenga G, Tshikae P, Lakan V, Mwamba T, Makowa H, Sangweni L, Mkhabela M, Zondo N, Mohulatsi E, Nyawo Z, Ngxongo S, Msimang S, Dagata N, Greenhouse B, Birkholtz LM, Shirreff G, Graffy R, Qwabe B, Moonasar D. High levels of imported asymptomatic malaria but limited local transmission in KwaZulu-Natal, a South African malaria-endemic province nearing malaria elimination. Malar J 2020; 19:152. [PMID: 32295590 PMCID: PMC7161075 DOI: 10.1186/s12936-020-03227-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 04/06/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND KwaZulu-Natal, one of South Africa's three malaria endemic provinces, is nearing malaria elimination, reporting fewer than 100 locally-acquired cases annually since 2010. Despite sustained implementation of essential interventions, including annual indoor residual spraying, prompt case detection using malaria rapid diagnostics tests and treatment with effective artemisinin-based combination therapy, low-level focal transmission persists in the province. This malaria prevalence and entomological survey was therefore undertaken to identify the drivers of this residual transmission. METHODS Malaria prevalence as well as malaria knowledge, attitudes and practices among community members and mobile migrant populations within uMkhanyakude district, KwaZulu-Natal were assessed during a community-based malaria prevalence survey. All consenting participants were tested for malaria by both conventional and highly-sensitive falciparum-specific rapid diagnostic tests. Finger-prick filter-paper blood spots were also collected from all participants for downstream parasite genotyping analysis. Entomological investigations were conducted around the surveyed households, with potential breeding sites geolocated and larvae collected for species identification and insecticide susceptibility testing. A random selection of households were assessed for indoor residual spray quality by cone bioassay. RESULTS A low malaria prevalence was confirmed in the study area, with only 2% (67/2979) of the participants found to be malaria positive by both conventional and highly-sensitive falciparum-specific rapid diagnostic tests. Malaria prevalence however differed markedly between the border market and community (p < 0001), with the majority of the detected malaria carriers (65/67) identified as asymptomatic Mozambican nationals transiting through the informal border market from Mozambique to economic hubs within South Africa. Genomic analysis of the malaria isolates revealed a high degree of heterozygosity and limited genetic relatedness between the isolates supporting the hypothesis of limited local malaria transmission within the province. New potential vector breeding sites, potential vector populations with reduced insecticide susceptibility and areas with sub-optimal vector intervention coverage were identified during the entomological investigations. CONCLUSION If KwaZulu-Natal is to successfully halt local malaria transmission and prevent the re-introduction of malaria, greater efforts need to be placed on detecting and treating malaria carriers at both formal and informal border crossings with transmission blocking anti-malarials, while ensuring optimal coverage of vector control interventions is achieved.
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Affiliation(s)
- Jaishree Raman
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg, Gauteng, South Africa. .,Wits Research Institute for Malaria, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, Gauteng, South Africa. .,UP Institute for Sustainable Malaria Control, Faculty of Health Sciences, University of Pretoria, Pretoria, Gauteng, South Africa.
| | - Laura Gast
- Clinton Health Access Initiative, Pretoria, Gauteng, South Africa
| | - Ryleen Balawanth
- Clinton Health Access Initiative, Pretoria, Gauteng, South Africa
| | - Sofonias Tessema
- Department of Medicine, University of California-San Francisco, San Francisco, USA
| | - Basil Brooke
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg, Gauteng, South Africa.,Wits Research Institute for Malaria, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, Gauteng, South Africa
| | - Rajendra Maharaj
- UP Institute for Sustainable Malaria Control, Faculty of Health Sciences, University of Pretoria, Pretoria, Gauteng, South Africa.,Office of Malaria Research, South African Medical Research Council, Durban, KwaZulu-Natal, South Africa
| | - Givemore Munhenga
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg, Gauteng, South Africa.,Wits Research Institute for Malaria, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, Gauteng, South Africa
| | - Power Tshikae
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg, Gauteng, South Africa
| | - Vishan Lakan
- Office of Malaria Research, South African Medical Research Council, Durban, KwaZulu-Natal, South Africa
| | - Tshiama Mwamba
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, a Division of the National Health Laboratory Service, Johannesburg, Gauteng, South Africa.,Wits Research Institute for Malaria, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, Gauteng, South Africa
| | - Hazel Makowa
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, Gauteng, South Africa
| | - Lindi Sangweni
- KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa
| | - Moses Mkhabela
- KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa
| | - Nompumelelo Zondo
- KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa
| | | | - Zuziwe Nyawo
- KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa
| | - Sifiso Ngxongo
- KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa
| | - Sipho Msimang
- KwaZulu-Natal Provincial Department of Health, Pietermaritzburg, KwaZulu-Natal, South Africa
| | - Nicole Dagata
- Clinton Health Access Initiative, Pretoria, Gauteng, South Africa
| | - Bryan Greenhouse
- Department of Medicine, University of California-San Francisco, San Francisco, USA
| | - Lyn-Marie Birkholtz
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, Gauteng, South Africa
| | - George Shirreff
- Clinton Health Access Initiative, Pretoria, Gauteng, South Africa
| | - Rebecca Graffy
- Clinton Health Access Initiative, Pretoria, Gauteng, South Africa
| | - Bheki Qwabe
- KwaZulu-Natal Provincial Malaria Control Programme, Jozini, KwaZulu-Natal, South Africa
| | - Devanand Moonasar
- UP Institute for Sustainable Malaria Control, Faculty of Health Sciences, University of Pretoria, Pretoria, Gauteng, South Africa.,Malaria Vector Borne and Zoonotic Diseases, National Department of Health, Pretoria, Gauteng, South Africa
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