1
|
García GA, Janko M, Hergott DEB, Donfack OT, Smith JM, Mba Eyono JN, DeBoer KR, Nguema Avue RM, Phiri WP, Aldrich EM, Schwabe C, Stabler TC, Rivas MR, Cameron E, Guerra CA, Cook J, Kleinschmidt I, Bradley J. Identifying individual, household and environmental risk factors for malaria infection on Bioko Island to inform interventions. Malar J 2023; 22:72. [PMID: 36859263 PMCID: PMC9979414 DOI: 10.1186/s12936-023-04504-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 02/18/2023] [Indexed: 03/03/2023] Open
Abstract
BACKGROUND Since 2004, malaria transmission on Bioko Island has declined significantly as a result of the scaling-up of control interventions. The aim of eliminating malaria from the Island remains elusive, however, underscoring the need to adapt control to the local context. Understanding the factors driving the risk of malaria infection is critical to inform optimal suits of interventions in this adaptive approach. METHODS This study used individual and household-level data from the 2015 and 2018 annual malaria indicator surveys on Bioko Island, as well as remotely-sensed environmental data in multilevel logistic regression models to quantify the odds of malaria infection. The analyses were stratified by urban and rural settings and by survey year. RESULTS Malaria prevalence was higher in 10-14-year-old children and similar between female and male individuals. After adjusting for demographic factors and other covariates, many of the variables investigated showed no significant association with malaria infection. The factor most strongly associated was history of travel to mainland Equatorial Guinea (mEG), which increased the odds significantly both in urban and rural settings (people who travelled had 4 times the odds of infection). Sleeping under a long-lasting insecticidal net decreased significantly the odds of malaria across urban and rural settings and survey years (net users had around 30% less odds of infection), highlighting their contribution to malaria control on the Island. Improved housing conditions indicated some protection, though this was not consistent across settings and survey year. CONCLUSIONS Malaria risk on Bioko Island is heterogeneous and determined by a combination of factors interacting with local mosquito ecology. These interactions grant further investigation in order to better adapt control according to need. The single most important risk factor identified was travel to mEG, in line with previous investigations, and represents a great challenge for the success of malaria control on the Island.
Collapse
Affiliation(s)
| | - Mark Janko
- Duke Global Health Institute, Duke University, Durham, NC, USA
| | - Dianna E B Hergott
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA
| | | | | | | | | | | | - Wonder P Phiri
- MCD Global Health, Bioko Island, Malabo, Equatorial Guinea
| | | | | | - Thomas C Stabler
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Matilde Riloha Rivas
- Equatorial Guinea Ministry of Health and Social Welfare, Bioko Island, Malabo, Equatorial Guinea
| | - Ewan Cameron
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
| | | | - Jackie Cook
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Immo Kleinschmidt
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
- School of Pathology, Faculty of Health Science, Wits Institute for Malaria Research, University of Witwatersrand, Johannesburg, South Africa
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| |
Collapse
|
2
|
Hauser M, Kabuya JBB, Mantus M, Kamavu LK, Sichivula JL, Matende WM, Fritschi N, Shields T, Curriero F, Kvit A, Chongwe G, Moss WJ, Ritz N, Ippolito MM. Malaria in Refugee Children Resettled to a Holoendemic Area of Sub-Saharan Africa. Clin Infect Dis 2023; 76:e1104-e1113. [PMID: 35640824 PMCID: PMC10169438 DOI: 10.1093/cid/ciac417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 05/06/2022] [Accepted: 05/20/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Malaria is a leading cause of morbidity and mortality in refugee children in high-transmission parts of Africa. Characterizing the clinical features of malaria in refugees can inform approaches to reduce its burden. METHODS The study was conducted in a high-transmission region of northern Zambia hosting Congolese refugees. We analyzed surveillance data and hospital records of children with severe malaria from refugee and local sites using multivariable regression models and geospatial visualization. RESULTS Malaria prevalence in the refugee settlement was similar to the highest burden areas in the district, consistent with the local ecology and leading to frequent rapid diagnostic test stockouts. We identified 2197 children hospitalized for severe malaria during the refugee crisis in 2017 and 2018. Refugee children referred from a refugee transit center (n = 63) experienced similar in-hospital mortality to local children and presented with less advanced infection. However, refugee children from a permanent refugee settlement (n = 110) had more than double the mortality of local children (P < .001), had lower referral rates, and presented more frequently with advanced infection and malnutrition. Distance from the hospital was an important mediator of the association between refugee status and mortality but did not account for all of the increased risk. CONCLUSIONS Malaria outcomes were more favorable in refugee children referred from a highly outfitted refugee transit center than those referred later from a permanent refugee settlement. Refugee children experienced higher in-hospital malaria mortality due in part to delayed presentation and higher rates of malnutrition. Interventions tailored to the refugee context are required to ensure capacity for rapid diagnosis and referral to reduce malaria mortality.
Collapse
Affiliation(s)
- Manuela Hauser
- Faculty of Medicine, University of Basel, Basel, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Jean-Bertin B Kabuya
- Department of Clinical Sciences, Tropical Diseases Research Centre, Ndola, Zambia
| | - Molly Mantus
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Luc K Kamavu
- Office of Hospital Administration, Saint Paul's General Hospital, Nchelenge, Zambia
| | - James L Sichivula
- Department of Clinical Sciences, Tropical Diseases Research Centre, Ndola, Zambia
| | - Wycliffe M Matende
- United Nations High Commissioner for Refugees, Country Representation Office, Lusaka, Zambia
| | - Nora Fritschi
- Mycobacterial and Migrant Health Research Group, University of Basel Children's Hospital, Basel, Switzerland.,Department of Clinical Research, University of Basel, Basel, Switzerland
| | - Timothy Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Frank Curriero
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Anton Kvit
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Gershom Chongwe
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.,Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Nicole Ritz
- Mycobacterial and Migrant Health Research Group, University of Basel Children's Hospital, Basel, Switzerland.,Infectious Disease and Vaccinology Unit, University Children's Hospital Basel, University of Basel, Basel, Switzerland.,Department of Pediatrics, The Royal Children's Hospital Melbourne, The University of Melbourne, Melbourne, Australia.,Department of Paediatrics and Paediatric Infectious Diseases, Children's Hospital, Lucerne Cantonal Hospital, Lucerne, Switzerland
| | - Matthew M Ippolito
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.,Division of Clinical Pharmacology and Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
3
|
Hast M, Mharakurwa S, Shields TM, Lubinda J, Searle K, Gwanzura L, Munyati S, Moss WJ. Characterizing human movement patterns using GPS data loggers in an area of persistent malaria in Zimbabwe along the Mozambique border. BMC Infect Dis 2022; 22:942. [PMID: 36522643 PMCID: PMC9756631 DOI: 10.1186/s12879-022-07903-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Human mobility is a driver for the reemergence or resurgence of malaria and has been identified as a source of cross-border transmission. However, movement patterns are difficult to measure in rural areas where malaria risk is high. In countries with malaria elimination goals, it is essential to determine the role of mobility on malaria transmission to implement appropriate interventions. METHODS A study was conducted in Mutasa District, Zimbabwe, to investigate human movement patterns in an area of persistent transmission along the Mozambique border. Over 1 year, a convenience sample of 20 participants/month was recruited from active malaria surveillance cohorts to carry an IgotU® GT-600 global positioning system (GPS) data logger during all daily activities. Consenting participants were tested for malaria at data logger distribution using rapid antigen diagnostic tests and completed a survey questionnaire. GPS data were analyzed using a trajectory analysis tool, and participant movement patterns were characterized throughout the study area and across the border into Mozambique using movement intensity maps, activity space plots, and statistical analyses. RESULTS From June 2016-May 2017, 184 participants provided movement tracks encompassing > 350,000 data points and nearly 8000 person-days. Malaria prevalence at logger distribution was 3.7%. Participants traveled a median of 2.8 km/day and spent a median of 4.6 h/day away from home. Movement was widespread within and outside the study area, with participants traveling up to 500 km from their homes. Indices of mobility were higher in the dry season than the rainy season (median km traveled/day = 3.5 vs. 2.2, P = 0.03), among male compared to female participants (median km traveled/day = 3.8 vs. 2.0, P = 0.0008), and among adults compared to adolescents (median total km traveled = 104.6 vs. 59.5, P = 0.05). Half of participants traveled outside the study area, and 30% traveled into Mozambique, including 15 who stayed in Mozambique overnight. CONCLUSIONS Study participants in Mutasa District, Zimbabwe, were highly mobile throughout the year. Many participants traveled long distances from home, including overnight trips into Mozambique, with clear implications for malaria control. Interventions targeted at mobile populations and cross-border transmission may be effective in preventing malaria introductions in this region.
Collapse
Affiliation(s)
- Marisa Hast
- grid.21107.350000 0001 2171 9311Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
| | - Sungano Mharakurwa
- grid.418347.d0000 0004 8265 7435Biomedical Research and Training Institute, Harare, Zimbabwe ,grid.442719.d0000 0000 8930 0245Africa University, Old Mutare, Mutare, Zimbabwe
| | - Timothy M. Shields
- grid.21107.350000 0001 2171 9311Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
| | - Jailos Lubinda
- grid.414659.b0000 0000 8828 1230Telethon Kids Institute, Malaria Atlas Project, Nedlands, WA Australia
| | - Kelly Searle
- grid.17635.360000000419368657School of Public Health, University of Minnesota, Minneapolis, MN USA
| | - Lovemore Gwanzura
- grid.418347.d0000 0004 8265 7435Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Shungu Munyati
- grid.418347.d0000 0004 8265 7435Biomedical Research and Training Institute, Harare, Zimbabwe
| | - William J. Moss
- grid.21107.350000 0001 2171 9311Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
| |
Collapse
|
4
|
Investigating differences in village-level heterogeneity of malaria infection and household risk factors in Papua New Guinea. Sci Rep 2021; 11:16540. [PMID: 34400687 PMCID: PMC8367982 DOI: 10.1038/s41598-021-95959-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/27/2021] [Indexed: 11/13/2022] Open
Abstract
Malaria risk is highly heterogeneous. Understanding village and household-level spatial heterogeneity of malaria risk can support a transition to spatially targeted interventions for malaria elimination. This analysis uses data from cross-sectional prevalence surveys conducted in 2014 and 2016 in two villages (Megiar and Mirap) in Papua New Guinea. Generalised additive modelling was used to characterise spatial heterogeneity of malaria risk and investigate the contribution of individual, household and environmental-level risk factors. Following a period of declining malaria prevalence, the prevalence of P. falciparum increased from 11.4 to 19.1% in Megiar and 12.3 to 28.3% in Mirap between 2014 and 2016, with focal hotspots observed in these villages in 2014 and expanding in 2016. Prevalence of P. vivax was similar in both years (20.6% and 18.3% in Megiar, 22.1% and 23.4% in Mirap) and spatial risk heterogeneity was less apparent compared to P. falciparum. Within-village hotspots varied by Plasmodium species across time and between villages. In Megiar, the adjusted odds ratio (AOR) of infection could be partially explained by household factors that increase risk of vector exposure, such as collecting outdoor surface water as a main source of water. In Mirap, increased AOR overlapped with proximity to densely vegetated areas of the village. The identification of household and environmental factors associated with increased spatial risk may serve as useful indicators of transmission hotspots and inform the development of tailored approaches for malaria control.
Collapse
|
5
|
Odhiambo JN, Kalinda C, Macharia PM, Snow RW, Sartorius B. Spatial and spatio-temporal methods for mapping malaria risk: a systematic review. BMJ Glob Health 2021; 5:bmjgh-2020-002919. [PMID: 33023880 PMCID: PMC7537142 DOI: 10.1136/bmjgh-2020-002919] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 12/21/2022] Open
Abstract
Background Approaches in malaria risk mapping continue to advance in scope with the advent of geostatistical techniques spanning both the spatial and temporal domains. A substantive review of the merits of the methods and covariates used to map malaria risk has not been undertaken. Therefore, this review aimed to systematically retrieve, summarise methods and examine covariates that have been used for mapping malaria risk in sub-Saharan Africa (SSA). Methods A systematic search of malaria risk mapping studies was conducted using PubMed, EBSCOhost, Web of Science and Scopus databases. The search was restricted to refereed studies published in English from January 1968 to April 2020. To ensure completeness, a manual search through the reference lists of selected studies was also undertaken. Two independent reviewers completed each of the review phases namely: identification of relevant studies based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, data extraction and methodological quality assessment using a validated scoring criterion. Results One hundred and seven studies met the inclusion criteria. The median quality score across studies was 12/16 (range: 7–16). Approximately half (44%) of the studies employed variable selection techniques prior to mapping with rainfall and temperature selected in over 50% of the studies. Malaria incidence (47%) and prevalence (35%) were the most commonly mapped outcomes, with Bayesian geostatistical models often (31%) the preferred approach to risk mapping. Additionally, 29% of the studies employed various spatial clustering methods to explore the geographical variation of malaria patterns, with Kulldorf scan statistic being the most common. Model validation was specified in 53 (50%) studies, with partitioning data into training and validation sets being the common approach. Conclusions Our review highlights the methodological diversity prominent in malaria risk mapping across SSA. To ensure reproducibility and quality science, best practices and transparent approaches should be adopted when selecting the statistical framework and covariates for malaria risk mapping. Findings underscore the need to periodically assess methods and covariates used in malaria risk mapping; to accommodate changes in data availability, data quality and innovation in statistical methodology.
Collapse
Affiliation(s)
| | - Chester Kalinda
- Discipline of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa.,Faculty of Agriculture and Natural Resources, University of Namibia, Windhoek, Namibia
| | - Peter M Macharia
- Population Health Unit, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Robert W Snow
- Population Health Unit, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Benn Sartorius
- Discipline of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa.,Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| |
Collapse
|
6
|
Lubinda J, Haque U, Bi Y, Shad MY, Keellings D, Hamainza B, Moore AJ. Climate change and the dynamics of age-related malaria incidence in Southern Africa. ENVIRONMENTAL RESEARCH 2021; 197:111017. [PMID: 33766570 DOI: 10.1016/j.envres.2021.111017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 02/27/2021] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
In the last decade, many malaria-endemic countries, like Zambia, have achieved significant reductions in malaria incidence among children <5 years old but face ongoing challenges in achieving similar progress against malaria in older age groups. In parts of Zambia, changing climatic and environmental factors are among those suspectedly behind high malaria incidence. Changes and variations in these factors potentially interfere with intervention program effectiveness and alter the distribution and incidence patterns of malaria differentially between young children and the rest of the population. We used parametric and non-parametric statistics to model the effects of climatic and socio-demographic variables on age-specific malaria incidence vis-à-vis control interventions. Linear regressions, mixed models, and Mann-Kendall tests were implemented to explore trends, changes in trends, and regress malaria incidence against environmental and intervention variables. Our study shows that while climate parameters affect the whole population, their impacts are felt most by people aged ≥5 years. Climate variables influenced malaria substantially more than mosquito nets and indoor residual spraying interventions. We establish that climate parameters negatively impact malaria control efforts by exacerbating the transmission conditions via more conducive temperature and rainfall environments, which are augmented by cultural and socioeconomic exposure mechanisms. We argue that an intensified communications and education intervention strategy for behavioural change specifically targeted at ≥5 aged population where incidence rates are increasing, is urgently required and call for further malaria stratification among the ≥5 age groups in the routine collection, analysis and reporting of malaria mortality and incidence data.
Collapse
Affiliation(s)
- Jailos Lubinda
- School of Geography and Environmental Sciences, Ulster University, Coleraine, UK; School of Computing, Engineering and Intelligent Systems, Ulster University, Londonderry, United Kingdom; School of Nursing, Faculty of Life & Health Sciences, Jordanstown, Newtownabbey, United Kingdom.
| | - Ubydul Haque
- Department of Biostatistics and Epidemiology, University of North Texas Health Science Centre, Fort Worth, TX, 76107, USA; Department of Geography, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Yaxin Bi
- School of Computing, Ulster University, Jordanstown, Newtownabbey, UK
| | | | - David Keellings
- Department of Geography, University of Alabama, Tuscaloosa, AL, USA
| | - Busiku Hamainza
- Ministry of Health, National Malaria Elimination Center, Lusaka, Zambia
| | - Adrian J Moore
- School of Geography and Environmental Sciences, Ulster University, Coleraine, UK
| |
Collapse
|
7
|
Near-term climate change impacts on sub-national malaria transmission. Sci Rep 2021; 11:751. [PMID: 33436862 PMCID: PMC7803742 DOI: 10.1038/s41598-020-80432-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 12/17/2020] [Indexed: 01/29/2023] Open
Abstract
The role of climate change on global malaria is often highlighted in World Health Organisation reports. We modelled a Zambian socio-environmental dataset from 2000 to 2016, against malaria trends and investigated the relationship of near-term environmental change with malaria incidence using Bayesian spatio-temporal, and negative binomial mixed regression models. We introduced the diurnal temperature range (DTR) as an alternative environmental measure to the widely used mean temperature. We found substantial sub-national near-term variations and significant associations with malaria incidence-trends. Significant spatio-temporal shifts in DTR/environmental predictors influenced malaria incidence-rates, even in areas with declining trends. We highlight the impact of seasonally sensitive DTR, especially in the first two quarters of the year and demonstrate how substantial investment in intervention programmes is negatively impacted by near-term climate change, most notably since 2010. We argue for targeted seasonally-sensitive malaria chemoprevention programmes.
Collapse
|
8
|
Hast MA, Stevenson JC, Muleba M, Chaponda M, Kabuya JB, Mulenga M, Shields T, Moss WJ, Norris DE, For The Southern And Central Africa International Centers Of Excellence In Malaria Research. The Impact of Three Years of Targeted Indoor Residual Spraying with Pirimiphos-Methyl on Household Vector Abundance in a High Malaria Transmission Area of Northern Zambia. Am J Trop Med Hyg 2020; 104:683-694. [PMID: 33350376 PMCID: PMC7866301 DOI: 10.4269/ajtmh.20-0537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 10/13/2020] [Indexed: 11/07/2022] Open
Abstract
The global malaria burden has decreased substantially, but gains have been uneven both within and between countries. In Zambia, the malaria burden remains high in northern and eastern regions of the country. To effectively reduce malaria transmission in these areas, evidence-based intervention strategies are needed. Zambia’s National Malaria Control Centre conducted targeted indoor residual spraying (IRS) in 40 high-burden districts from 2014 to 2016 using the novel organophosphate insecticide pirimiphos-methyl. The Southern and Central Africa International Centers of Excellence for Malaria Research conducted an evaluation of the impact of the IRS campaign on household vector abundance in Nchelenge District, Luapula Province. From April 2012 to July 2017, field teams conducted indoor overnight vector collections from 25 to 30 households per month using Centers for Disease Control light traps. Changes in indoor anopheline counts before versus after IRS were assessed by species using negative binomial regression models with robust standard errors, controlling for geographic and climatological covariates. Counts of Anopheles funestus declined by approximately 50% in the study area and within areas targeted for IRS, and counts of Anopheles gambiae declined by approximately 40%. Within targeted areas, An. funestus counts declined more in sprayed households than in unsprayed households; however, this relationship was not observed for An. gambiae. The moderate decrease in indoor vector abundance indicates that IRS with pirimiphos-methyl is an effective vector control measure, but a more comprehensive package of interventions is needed with sufficient coverage to effectively reduce the malaria burden in this setting.
Collapse
Affiliation(s)
- Marisa A Hast
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jennifer C Stevenson
- Macha Research Trust, Choma, Zambia.,W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Mbanga Muleba
- The Tropical Diseases Research Centre, Ndola, Zambia
| | - Mike Chaponda
- The Tropical Diseases Research Centre, Ndola, Zambia
| | | | - Modest Mulenga
- Department of Public Health, Michael Chilufya Sata School of Medicine, The Copperbelt University, Kitwe, Zambia
| | - Timothy Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J Moss
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Douglas E Norris
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | |
Collapse
|
9
|
Ippolito MM, Pringle JC, Siame M, Katowa B, Aydemir O, Oluoch PO, Huang L, Aweeka FT, Bailey JA, Juliano JJ, Meshnick SR, Shapiro TA, Moss WJ, Thuma PE. Therapeutic Efficacy of Artemether-Lumefantrine for Uncomplicated Falciparum Malaria in Northern Zambia. Am J Trop Med Hyg 2020; 103:2224-2232. [PMID: 33078701 DOI: 10.4269/ajtmh.20-0852] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Artemether-lumefantrine (AL) is a first-line agent for uncomplicated malaria caused by Plasmodium falciparum. The WHO recommends periodic therapeutic efficacy studies of antimalarial drugs for the detection of malaria parasite drug resistance and to inform national malaria treatment policies. We conducted a therapeutic efficacy study of AL in a high malaria transmission region of northern Zambia from December 2014 to July 2015. One hundred children of ages 6 to 59 months presenting to a rural health clinic with uncomplicated falciparum malaria were admitted for treatment with AL (standard 6-dose regimen) and followed weekly for 5 weeks. Parasite counts were taken every 6 hours during treatment to assess parasite clearance. Recurrent episodes during follow-up (n = 14) were genotyped to distinguish recrudescence from reinfection and to identify drug resistance single nucleotide polymorphisms (SNPs) and multidrug resistance protein 1 (mdr1) copy number variation. Day 7 lumefantrine concentrations were measured for correspondence with posttreatment reinfection. All children who completed the parasite clearance portion of the study (n = 94) were microscopy-negative by 72 hours. The median parasite elimination half-life was 2.7 hours (interquartile range: 2.1-3.3). Genotype-corrected therapeutic efficacy was 98.8% (95% CI: 97.6-100). Purported artemisinin and lumefantrine drug resistance SNPs in atp6, 3D7_1451200, and mdr1 were detected but did not correlate with parasite recurrence, nor did day 7 lumefantrine concentrations. In summary, AL was highly effective for the treatment of uncomplicated falciparum malaria in northern Zambia during the study period. The high incidence of recurrent parasitemia was consistent with reinfection due to high, perennial malaria transmission.
Collapse
Affiliation(s)
- Matthew M Ippolito
- The Johns Hopkins Malaria Research Institute, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland.,Division of Clinical Pharmacology, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Julia C Pringle
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
| | - Mwiche Siame
- Ministry of Health, Government of the Republic of Zambia, Lusaka, Zambia
| | | | - Ozkan Aydemir
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island
| | - Peter O Oluoch
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island
| | - Liusheng Huang
- Department of Clinical Pharmacology, University of California San Francisco School of Pharmacy, San Francisco, California
| | - Francesca T Aweeka
- Department of Clinical Pharmacology, University of California San Francisco School of Pharmacy, San Francisco, California
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island
| | - Jonathan J Juliano
- Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Steven R Meshnick
- Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina
| | - Theresa A Shapiro
- The Johns Hopkins Malaria Research Institute, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland.,Division of Clinical Pharmacology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - William J Moss
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland.,The Johns Hopkins Malaria Research Institute, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland.,W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
| | - Philip E Thuma
- Macha Research Trust, Macha, Zambia.,The Johns Hopkins Malaria Research Institute, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
| |
Collapse
|
10
|
Ryan SJ, Martin AC, Walia B, Winters A, Larsen DA. Comparing prioritization strategies for delivering indoor residual spray (IRS) implementation, using a network approach. Malar J 2020; 19:326. [PMID: 32887619 PMCID: PMC7650283 DOI: 10.1186/s12936-020-03398-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/30/2020] [Indexed: 11/28/2022] Open
Abstract
Background Indoor residual spraying (IRS) is an effective method to control malaria-transmitting Anopheles mosquitoes and often complements insecticide-treated mosquito nets, the predominant malaria vector control intervention. With insufficient funds to cover every household, malaria control programs must balance the malaria risk to a particular human community against the financial cost of spraying that community. This study creates a framework for modelling the distance to households for targeting IRS implementation, and applies it to potential risk prioritization strategies in four provinces (Luapula, Muchinga, Eastern, and Northern) in Zambia. Methods Optimal network models were used to assess the travel distance of routes between operations bases and human communities identified through remote sensing. Network travel distances were compared to Euclidean distances, to demonstrate the importance of accounting for road routes. The distance to reaching communities for different risk prioritization strategies were then compared assuming sufficient funds to spray 50% of households, using four underlying malarial risk maps: (a) predicted Plasmodium falciparum parasite rate in 2–10 years olds (PfPR), or (b) predicted probability of the presence of each of three main malaria transmitting anopheline vectors (Anopheles arabiensis, Anopheles funestus, Anopheles gambiae). Results The estimated one-way network route distance to reach communities to deliver IRS ranged from 0.05 to 115.69 km. Euclidean distance over and under-estimated these routes by − 101.21 to 41.79 km per trip, as compared to the network route method. There was little overlap between risk map prioritization strategies, both at a district-by-district scale, and across all four provinces. At both scales, agreement for inclusion or exclusion from IRS across all four prioritization strategies occurred in less than 10% of houses. The distances to reaching prioritized communities were either lower, or not statistically different from non-prioritized communities, at both scales of strategy. Conclusion Variation in distance to targeted communities differed depending on risk prioritization strategy used, and higher risk prioritization did not necessarily translate into greater distances in reaching a human community. These findings from Zambia suggest that areas with higher malaria burden may not necessarily be more remote than areas with lower malaria burden.
Collapse
Affiliation(s)
- Sadie J Ryan
- Quantitative Disease Ecology and Conservation (QDEC) Lab, Department of Geography, University of Florida, Gainesville, FL, 32611, USA. .,Emerging Pathogens Institute, University of Florida, Gainesville, FL, 32610, USA.
| | | | - Bhavneet Walia
- Department of Public Health, Syracuse University, Syracuse, NY, 13210, USA
| | - Anna Winters
- Akros, Lusaka, Zambia.,University of Montana School of Public and Community Health Science, Missoula, MT, USA
| | - David A Larsen
- Department of Public Health, Syracuse University, Syracuse, NY, 13210, USA
| |
Collapse
|
11
|
Bhondoekhan FRP, Searle KM, Hamapumbu H, Lubinda M, Matoba J, Musonda M, Katowa B, Shields TM, Kobayashi T, Norris DE, Curriero FC, Stevenson JC, Thuma PE, Moss WJ. Improving the efficiency of reactive case detection for malaria elimination in southern Zambia: a cross-sectional study. Malar J 2020; 19:175. [PMID: 32381005 PMCID: PMC7206707 DOI: 10.1186/s12936-020-03245-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/23/2020] [Indexed: 01/20/2023] Open
Abstract
Background Reactive case detection (RCD) seeks to enhance malaria surveillance and control by identifying and treating parasitaemic individuals residing near index cases. In Zambia, this strategy starts with passive detection of symptomatic incident malaria cases at local health facilities or by community health workers, with subsequent home visits to screen-and-treat residents in the index case and neighbouring (secondary) households within a 140-m radius using rapid diagnostic tests (RDTs). However, a small circular radius may not be the most efficient strategy to identify parasitaemic individuals in low-endemic areas with hotspots of malaria transmission. To evaluate if RCD efficiency could be improved by increasing the probability of identifying parasitaemic residents, environmental risk factors and a larger screening radius (250 m) were assessed in a region of low malaria endemicity. Methods Between January 12, 2015 and July 26, 2017, 4170 individuals residing in 158 index and 531 secondary households were enrolled and completed a baseline questionnaire in the catchment area of Macha Hospital in Choma District, Southern Province, Zambia. Plasmodium falciparum prevalence was measured using PfHRP2 RDTs and quantitative PCR (qPCR). A Quickbird™ high-resolution satellite image of the catchment area was used to create environmental risk factors in ArcGIS, and generalized estimating equations were used to evaluate associations between risk factors and secondary households with parasitaemic individuals. Results The parasite prevalence in secondary (non-index case) households was 0.7% by RDT and 1.8% by qPCR. Overall, 8.5% (n = 45) of secondary households had at least one resident with parasitaemia by qPCR or RDT. The risk of a secondary household having a parasitaemic resident was significantly increased in proximity to higher order streams and marginally with increasing distance from index households. The adjusted OR for proximity to third- and fifth-order streams were 2.97 (95% CI 1.04–8.42) and 2.30 (95% CI 1.04–5.09), respectively, and that for distance to index households for each 50 m was 1.24 (95% CI 0.98–1.58). Conclusion Applying proximity to streams as a screening tool, 16% (n = 3) more malaria-positive secondary households were identified compared to using a 140-m circular screening radius. This analysis highlights the potential use of environmental risk factors as a screening strategy to increase RCD efficiency.
Collapse
Affiliation(s)
- Fiona R P Bhondoekhan
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
| | - Kelly M Searle
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, USA
| | | | | | | | | | - Ben Katowa
- Macha Research Trust, Choma District, Zambia
| | - Timothy M Shields
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Tamaki Kobayashi
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Douglas E Norris
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Frank C Curriero
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Jennifer C Stevenson
- Macha Research Trust, Choma District, Zambia.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Philip E Thuma
- Macha Research Trust, Choma District, Zambia.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - William J Moss
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | | |
Collapse
|
12
|
Hast MA, Stevenson JC, Muleba M, Chaponda M, Kabuya JB, Mulenga M, Lessler J, Shields T, Moss WJ, Norris DE, For The Southern And Central Africa International Centers Of Excellence In Malaria Research. Risk Factors for Household Vector Abundance Using Indoor CDC Light Traps in a High Malaria Transmission Area of Northern Zambia. Am J Trop Med Hyg 2020; 101:126-136. [PMID: 31074411 DOI: 10.4269/ajtmh.18-0875] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Malaria transmission is dependent on the density and distribution of mosquito vectors, but drivers of vector abundance have not been adequately studied across a range of transmission settings. To inform intervention strategies for high-burden areas, further investigation is needed to identify predictors of vector abundance. Active household (HH) surveillance was conducted in Nchelenge district, Luapula Province, northern Zambia, a high-transmission setting with limited impact of malaria control. Between April 2012 and July 2017, mosquitoes were collected indoors during HH visits using CDC light traps. Demographic, environmental, and climatological correlates of vector abundance were identified using log-binomial regression models with robust standard errors. The primary malaria vectors in this setting were Anopheles funestus sensu stricto (s.s.) and Anopheles gambiae s.s. Anopheles funestus predominated in both seasons, with a peak in the dry season. Anopheles gambiae peaked at lower numbers in the rainy season. Environmental, climatic, and demographic factors were correlated with HH vector abundance. Higher vector counts were found in rural areas with low population density and among HHs close to roads and small streams. Vector counts were lower with increasing elevation and slope. Anopheles funestus was negatively associated with rainfall at lags of 2-6 weeks, and An. gambiae was positively associated with rainfall at lags of 3-10 weeks. Both vectors had varying relationships with temperature. These results suggest that malaria vector control in Nchelenge district should occur throughout the year, with an increased focus on dry-season transmission and rural areas.
Collapse
Affiliation(s)
- Marisa A Hast
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jennifer C Stevenson
- Macha Research Trust, Choma District, Zambia.,Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Mbanga Muleba
- The Tropical Diseases Research Centre, Ndola, Zambia
| | - Mike Chaponda
- The Tropical Diseases Research Centre, Ndola, Zambia
| | | | | | - Justin Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Timothy Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J Moss
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Douglas E Norris
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | |
Collapse
|
13
|
Hast MA, Chaponda M, Muleba M, Kabuya JB, Lupiya J, Kobayashi T, Shields T, Lessler J, Mulenga M, Stevenson JC, Norris DE, Moss WJ. The Impact of 3 Years of Targeted Indoor Residual Spraying With Pirimiphos-Methyl on Malaria Parasite Prevalence in a High-Transmission Area of Northern Zambia. Am J Epidemiol 2019; 188:2120-2130. [PMID: 31062839 DOI: 10.1093/aje/kwz107] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 01/06/2023] Open
Abstract
Malaria transmission in northern Zambia has increased in the past decade, despite malaria control activities. Evidence-based intervention strategies are needed to effectively reduce malaria transmission. Zambia's National Malaria Control Centre conducted targeted indoor residual spraying (IRS) in Nchelenge District, Luapula Province, from 2014 to 2016 using the organophosphate insecticide pirimiphos-methyl. An evaluation of the IRS campaign was conducted by the Southern Africa International Centers of Excellence for Malaria Research using actively detected malaria cases in bimonthly household surveys carried out from April 2012 to July 2017. Changes in malaria parasite prevalence after IRS were assessed by season using Poisson regression models with robust standard errors, controlling for clustering of participants in households and demographic, geographical, and climatological covariates. In targeted areas, parasite prevalence declined approximately 25% during the rainy season following IRS with pirimiphos-methyl but did not decline during the dry season or in the overall study area. Within targeted areas, parasite prevalence declined in unsprayed households, suggesting both direct and indirect effects of IRS. The moderate decrease in parasite prevalence within sprayed areas indicates that IRS with pirimiphos-methyl is an effective malaria control measure, but a more comprehensive package of interventions is needed to effectively reduce the malaria burden in this setting.
Collapse
Affiliation(s)
- Marisa A Hast
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | | | - James Lupiya
- Tropical Diseases Research Centre, Ndola, Zambia
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Timothy Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Justin Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Jennifer C Stevenson
- Department of Molecular Microbiology and Immunology and Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Macha Research Trust, Macha, Zambia
| | - Douglas E Norris
- Department of Molecular Microbiology and Immunology and Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Department of Molecular Microbiology and Immunology and Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| |
Collapse
|
14
|
Hast M, Searle KM, Chaponda M, Lupiya J, Lubinda J, Sikalima J, Kobayashi T, Shields T, Mulenga M, Lessler J, Moss WJ. The use of GPS data loggers to describe the impact of spatio-temporal movement patterns on malaria control in a high-transmission area of northern Zambia. Int J Health Geogr 2019; 18:19. [PMID: 31426819 PMCID: PMC6701131 DOI: 10.1186/s12942-019-0183-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 08/10/2019] [Indexed: 12/01/2022] Open
Abstract
Background Human movement is a driver of malaria transmission and has implications for sustainable malaria control. However, little research has been done on the impact of fine-scale movement on malaria transmission and control in high-transmission settings. As interest in targeted malaria control increases, evaluations are needed to determine the appropriateness of these strategies in the context of human mobility across a variety of transmission settings. Methods A human mobility study was conducted in Nchelenge District, a high-transmission setting in northern Zambia. Over 1 year, 84 participants were recruited from active malaria surveillance cohorts to wear a global positioning system data logger for 1 month during all daily activity. Participants completed a survey questionnaire and underwent malaria testing and treatment at the time of logger distribution and at collection 1 month later. Incident malaria infections were identified using polymerase chain reaction. Participant movement was characterized throughout the study area and across areas targeted for an indoor residual spraying (IRS) intervention. Participant movement patterns were compared using movement intensity maps, activity space plots, and statistical analyses. Malaria risk was characterized across participants using spatial risk maps and time spent away from home during peak vector biting hours. Results Movement data were collected from 82 participants, and 63 completed a second study visit. Participants exhibited diverse mobility patterns across the study area, including movement into and out of areas targeted for IRS, potentially mitigating the impact of IRS on parasite prevalence. Movement patterns did not differ significantly by season or age, but male participants traveled longer distances and spent more time away from home. Monthly malaria incidence was 22%, and malaria risk was characterized as high across participants. Participants with incident parasitemia traveled a shorter distance and spent more time away from home during peak biting hours; however, these relationships were not statistically significant, and malaria risk score did not differ by incident parasitemia. Conclusions Individual movement patterns in Nchelenge District, Zambia have implications for malaria control, particularly the effectiveness of targeted IRS strategies. Large and fine-scale population mobility patterns should be considered when planning intervention strategies across transmission settings. Electronic supplementary material The online version of this article (10.1186/s12942-019-0183-y) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Marisa Hast
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Kelly M Searle
- University of Minnesota, School of Public Health, Minneapolis, MN, USA
| | - Mike Chaponda
- The Tropical Diseases Research Centre, Ndola, Zambia
| | - James Lupiya
- The Tropical Diseases Research Centre, Ndola, Zambia
| | - Jailos Lubinda
- Macha Research Trust, Choma District, Choma, Zambia.,Ulster University, Coleraine, Northern Ireland, UK
| | - Jay Sikalima
- The Tropical Diseases Research Centre, Ndola, Zambia
| | - Tamaki Kobayashi
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Timothy Shields
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | | | - Justin Lessler
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - William J Moss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | | |
Collapse
|
15
|
Banda CG, Chaponda M, Mukaka M, Mulenga M, Hachizovu S, Kabuya JB, Mulenga J, Sikalima J, Kalilani-Phiri L, Terlouw DJ, Khoo SH, Lalloo DG, Mwapasa V. Efficacy and safety of artemether-lumefantrine as treatment for Plasmodium falciparum uncomplicated malaria in adult patients on efavirenz-based antiretroviral therapy in Zambia: an open label non-randomized interventional trial. Malar J 2019; 18:180. [PMID: 31126288 PMCID: PMC6534937 DOI: 10.1186/s12936-019-2818-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 05/18/2019] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND HIV-infected individuals on antiretroviral therapy (ART) require treatment with artemisinin-based combination therapy (ACT) when infected with malaria. Artemether-lumefantrine (AL) is the most commonly used ACT for treatment of falciparum malaria in Africa but there is limited evidence on the safety and efficacy of AL in HIV-infected individuals on ART, among whom drug-drug interactions are expected. Day-42 adequate clinical and parasitological response (ACPR) and incidence of adverse events was assessed in HIV-infected individuals on efavirenz-based ART with uncomplicated falciparum malaria treated with AL. METHODS A prospective, open label, non-randomized, interventional clinical trial was conducted at St Paul's Hospital in northern Zambia, involving 152 patients aged 15-65 years with uncomplicated falciparum malaria, who were on efavirenz-based ART. They received a 3-day directly observed standard treatment of AL and were followed up until day 63. Day-42 polymerase chain reaction (PCR)-corrected ACPRs (95% confidence interval [CI]) were calculated for the intention-to-treat population. RESULTS Enrolled patients had a baseline geometric mean (95% CI) parasite density of 1108 (841-1463) parasites/µL; 16.4% (25/152) of the participants had a recurrent malaria episode by day 42. However, PCR data was available for 17 out of the 25 patients who had malaria recurrence. Among all the 17 patients, PCR findings demonstrated malaria re-infection, making the PCR-adjusted day-42 ACPR 100% in the 144 patients who could be evaluated. Even when eight patients with missing PCR data were considered very conservatively as failures, the day-42 ACPR was over 94%. None of the participants, disease or treatment characteristics, including day-7 lumefantrine concentrations, predicted the risk of malaria recurrence by day 42. AL was well tolerated following administration. There were only two cases of grade 3 neutropaenia and one serious adverse event of lobar pneumonia, none of which was judged as probably related to intake of AL. CONCLUSIONS AL was well tolerated and efficacious in treating uncomplicated falciparum malaria in HIV co-infected adults on efavirenz-based ART. However, a higher than anticipated proportion of participants experienced malaria re-infection, which highlights the need for additional malaria prevention measures in this sub-population after treatment with AL. Trial registration Pan African Clinical Trials Registry (PACTR): PACTR201311000659400. Registered on 4 October 2013. https://pactr.samrc.ac.za/Search.aspx.
Collapse
Affiliation(s)
- Clifford G Banda
- University of Malawi, College of Medicine, Blantyre, Malawi.
- Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi.
| | | | - Mavuto Mukaka
- University of Malawi, College of Medicine, Blantyre, Malawi
- Oxford Centre for Tropical Medicine and Global Health, Oxford, UK
- Mahidol-Oxford Tropical Medicine Research Unit, Bangkok, Thailand
| | | | | | | | | | - Jay Sikalima
- Tropical Diseases Research Centre, Ndola, Zambia
| | | | - Dianne J Terlouw
- Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Saye H Khoo
- University of Liverpool, Liverpool, UK
- Tropical and Infectious Diseases Unit, Royal Liverpool University Hospital, Liverpool, UK
| | - David G Lalloo
- Liverpool School of Tropical Medicine, Liverpool, UK
- Tropical and Infectious Diseases Unit, Royal Liverpool University Hospital, Liverpool, UK
| | - Victor Mwapasa
- University of Malawi, College of Medicine, Blantyre, Malawi.
- Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi.
| |
Collapse
|
16
|
Amratia P, Psychas P, Abuaku B, Ahorlu C, Millar J, Oppong S, Koram K, Valle D. Characterizing local-scale heterogeneity of malaria risk: a case study in Bunkpurugu-Yunyoo district in northern Ghana. Malar J 2019; 18:81. [PMID: 30876413 PMCID: PMC6420752 DOI: 10.1186/s12936-019-2703-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 03/02/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Bayesian methods have been used to generate country-level and global maps of malaria prevalence. With increasing availability of detailed malaria surveillance data, these methodologies can also be used to identify fine-scale heterogeneity of malaria parasitaemia for operational prevention and control of malaria. METHODS In this article, a Bayesian geostatistical model was applied to six malaria parasitaemia surveys conducted during rainy and dry seasons between November 2010 and 2013 to characterize the micro-scale spatial heterogeneity of malaria risk in northern Ghana. RESULTS The geostatistical model showed substantial spatial heterogeneity, with malaria parasite prevalence varying between 19 and 90%, and revealing a northeast to southwest gradient of predicted risk. The spatial distribution of prevalence was heavily influenced by two modest urban centres, with a substantially lower prevalence in urban centres compared to rural areas. Although strong seasonal variations were observed, spatial malaria prevalence patterns did not change substantially from year to year. Furthermore, independent surveillance data suggested that the model had a relatively good predictive performance when extrapolated to a neighbouring district. CONCLUSIONS This high variability in malaria prevalence is striking, given that this small area (approximately 30 km × 40 km) was purportedly homogeneous based on country-level spatial analysis, suggesting that fine-scale parasitaemia data might be critical to guide district-level programmatic efforts to prevent and control malaria. Extrapolations results suggest that fine-scale parasitaemia data can be useful for spatial predictions in neighbouring unsampled districts and does not have to be collected every year to aid district-level operations, helping to alleviate concerns regarding the cost of fine-scale data collection.
Collapse
Affiliation(s)
- Punam Amratia
- School of Forest Resources and Conservation, University of Florida, Gainesville, USA. .,Emerging Pathogens Institute, University of Florida, Gainesville, USA.
| | - Paul Psychas
- Emerging Pathogens Institute, University of Florida, Gainesville, USA
| | - Benjamin Abuaku
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Collins Ahorlu
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Justin Millar
- School of Forest Resources and Conservation, University of Florida, Gainesville, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, USA
| | | | - Kwadwo Koram
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Denis Valle
- School of Forest Resources and Conservation, University of Florida, Gainesville, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, USA
| |
Collapse
|
17
|
Nawa M, Hangoma P, Morse AP, Michelo C. Investigating the upsurge of malaria prevalence in Zambia between 2010 and 2015: a decomposition of determinants. Malar J 2019; 18:61. [PMID: 30845998 PMCID: PMC6407176 DOI: 10.1186/s12936-019-2698-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 03/01/2019] [Indexed: 11/22/2022] Open
Abstract
Background Malaria is among the top causes of mortality and morbidity in Zambia. Efforts to control, prevent, and eliminate it have been intensified in the past two decades which has contributed to reductions in malaria prevalence and under-five mortality. However, there was a 21% upsurge in malaria prevalence between 2010 and 2015. Zambia is one of the only 13 countries to record an increase in malaria among 91 countries monitored by the World Health Organization in 2015. This study investigated the upsurge by decomposition of drivers of malaria. Methods The study used secondary data from three waves of nationally representative cross-sectional surveys on key malaria indicators conducted in 2010, 2012 and 2015. Using multivariable logistic regression, determinants of malaria prevalence were identified and then marginal effects of each determinant were derived. The marginal effects were then combined with changes in coverage rates of determinants between 2010 and 2015 to obtain the magnitude of how much each variable contributed to the change in the malaria prevalence. Results The odds ratio of malaria for those who slept under an insecticide-treated net (ITN) was 0.90 (95% CI 0.77–0.97), indoor residual spraying (IRS) was 0.66 (95% CI 0.49–0.89), urban residence was 0.23 (95% CI 0.15–0.37), standard house was 0.40 (95% CI 0.35–0.71) and age group 12–59 Months against those below 12 months was 4.04 (95% CI 2.80–5.81). Decomposition of prevalence changes by determinants showed that IRS reduced malaria prevalence by − 0.3% and ITNs by − 0.2% however, these reductions were overridden by increases in prevalence due to increases in the proportion of more at-risk children aged 12–59 months by + 2.3% and rural residents by + 2.2%. Conclusion The increases in interventions, such as ITNs and IRS, were shown to have contributed to malaria reduction in 2015; however, changes in demographics such as increases in the proportion of more at risk groups among under-five children and rural residents may have overridden the impact of these interventions and resulted in an overall increase. The upsurge in malaria in 2015 compared to 2010 may not have been due to weaknesses in programme interventions but due to increases in more at-risk children and rural residents compared to 2010. The apparent increase in rural residents in the sample population may not have been a true reflection of the population structure but due to oversampling in rural areas which was not fully adjusted for. The increase in malaria prevalence may therefore have been overestimated.
Collapse
Affiliation(s)
- Mukumbuta Nawa
- School of Public Health, University of Zambia, Ridgeway Campus, Lusaka, Zambia.
| | - Peter Hangoma
- School of Public Health, University of Zambia, Ridgeway Campus, Lusaka, Zambia
| | - Andrew P Morse
- Department of Geography and Planning, University of Liverpool, Liverpool, UK
| | - Charles Michelo
- School of Public Health, University of Zambia, Ridgeway Campus, Lusaka, Zambia
| |
Collapse
|
18
|
Cohen JM, Le Menach A, Pothin E, Eisele TP, Gething PW, Eckhoff PA, Moonen B, Schapira A, Smith DL. Mapping multiple components of malaria risk for improved targeting of elimination interventions. Malar J 2017; 16:459. [PMID: 29132357 PMCID: PMC5683539 DOI: 10.1186/s12936-017-2106-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/02/2017] [Indexed: 11/13/2022] Open
Abstract
There is a long history of considering the constituent components of malaria risk and the malaria transmission cycle via the use of mathematical models, yet strategic planning in endemic countries tends not to take full advantage of available disease intelligence to tailor interventions. National malaria programmes typically make operational decisions about where to implement vector control and surveillance activities based upon simple categorizations of annual parasite incidence. With technological advances, an enormous opportunity exists to better target specific malaria interventions to the places where they will have greatest impact by mapping and evaluating metrics related to a variety of risk components, each of which describes a different facet of the transmission cycle. Here, these components and their implications for operational decision-making are reviewed. For each component, related mappable malaria metrics are also described which may be measured and evaluated by malaria programmes seeking to better understand the determinants of malaria risk. Implementing tailored programmes based on knowledge of the heterogeneous distribution of the drivers of malaria transmission rather than only consideration of traditional metrics such as case incidence has the potential to result in substantial improvements in decision-making. As programmes improve their ability to prioritize their available tools to the places where evidence suggests they will be most effective, elimination aspirations may become increasingly feasible.
Collapse
Affiliation(s)
- Justin M Cohen
- Clinton Health Access Initiative, 383 Dorchester Ave., Suite 400, Boston, MA, 02127, USA.
| | - Arnaud Le Menach
- Clinton Health Access Initiative, 383 Dorchester Ave., Suite 400, Boston, MA, 02127, USA
| | - Emilie Pothin
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland
| | - Thomas P Eisele
- Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, 1440 Canal St (2300), New Orleans, LA, 70112, USA
| | - Peter W Gething
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7LF, UK
| | - Philip A Eckhoff
- Institute for Disease Modeling, Building IV, 3150 139th Ave SE, Bellevue, WA, 98005, USA
| | - Bruno Moonen
- Bill & Melinda Gates Foundation, PO Box 23350, Seattle, WA, 98102, USA
| | | | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, 2301 Fifth Ave., Suite 600, Seattle, WA, 98121, USA
| |
Collapse
|
19
|
Nambozi M, Kabuya JBB, Hachizovu S, Mwakazanga D, Mulenga J, Kasongo W, Buyze J, Mulenga M, Van Geertruyden JP, D'Alessandro U. Artemisinin-based combination therapy in pregnant women in Zambia: efficacy, safety and risk of recurrent malaria. Malar J 2017; 16:199. [PMID: 28511713 PMCID: PMC5434531 DOI: 10.1186/s12936-017-1851-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 05/09/2017] [Indexed: 11/10/2022] Open
Abstract
Background In Zambia, malaria is one of the leading causes of morbidity and mortality, especially among under five children and pregnant women. For the latter, the World Health Organization recommends the use of artemisinin-based combination therapy (ACT) in the second and third trimester of pregnancy. In a context of limited information on ACT, the safety and efficacy of three combinations, namely artemether–lumefantrine (AL), mefloquine–artesunate (MQAS) and dihydroartemisinin–piperaquine (DHAPQ) were assessed in pregnant women with malaria. Methods The trial was carried out between July 2010 and August 2013 in Nchelenge district, Luapula Province, an area of high transmission, as part of a multi-centre trial. Women in the second or third trimester of pregnancy and with malaria were recruited and randomized to one of the three study arms. Women were actively followed up for 63 days, and then at delivery and 1 year post-delivery. Results Nine hundred pregnant women were included, 300 per arm. PCR-adjusted treatment failure was 4.7% (12/258) (95% CI 2.7–8.0) for AL, 1.3% (3/235) (95% CI 0.4–3.7) for MQAS and 0.8% (2/236) (95% CI 0.2–3.0) for DHAPQ, with significant risk difference between AL and DHAPQ (p = 0.01) and between AL and MQAS (p = 0.03) treatments. Re-infections during follow up were more frequent in the AL (HR: 4.71; 95% CI 3.10–7.2; p < 0.01) and MQAS (HR: 1.59; 95% CI 1.02–2.46; p = 0.04) arms compared to the DHAPQ arm. PCR-adjusted treatment failure was significantly associated with women under 20 years [Hazard Ratio (HR) 5.35 (95% CI 1.07–26.73; p = 0.04)] and higher malaria parasite density [3.23 (95% CI 1.03–10.10; p = 0.04)], and still women under 20 years [1.78, (95% CI 1.26–2.52; p < 0.01)] had a significantly higher risk of re-infection. The three treatments were generally well tolerated. Dizziness, nausea, vomiting, headache and asthenia as adverse events (AEs) were more common in MQAS than in AL or DHAPQ (p < 0.001). Birth outcomes were not significantly different between treatment arms. Conclusion As new infections can be prevented by a long acting partner drug to the artemisinins, DHAPQ should be preferred in places as Nchelenge district where transmission is intense while in areas of low transmission intensity AL or MQAS may be used.
Collapse
Affiliation(s)
- Michael Nambozi
- Department of Clinical Sciences, Tropical Diseases Research Centre, P.O Box 71769, Ndola, Zambia.
| | | | - Sebastian Hachizovu
- Department of Clinical Sciences, Tropical Diseases Research Centre, P.O Box 71769, Ndola, Zambia
| | - David Mwakazanga
- Department of Clinical Sciences, Tropical Diseases Research Centre, P.O Box 71769, Ndola, Zambia
| | - Joyce Mulenga
- Department of Clinical Sciences, Tropical Diseases Research Centre, P.O Box 71769, Ndola, Zambia
| | - Webster Kasongo
- Department of Clinical Sciences, Tropical Diseases Research Centre, P.O Box 71769, Ndola, Zambia
| | | | - Modest Mulenga
- Department of Clinical Sciences, Tropical Diseases Research Centre, P.O Box 71769, Ndola, Zambia
| | | | - Umberto D'Alessandro
- Institute of Tropical Medicine, Antwerp, Belgium.,Medical Research Council Unit, Serekunda, Gambia.,London School of Hygiene and Tropical Medicine, London, UK
| |
Collapse
|
20
|
Stevenson JC, Pinchoff J, Muleba M, Lupiya J, Chilusu H, Mwelwa I, Mbewe D, Simubali L, Jones CM, Chaponda M, Coetzee M, Mulenga M, Pringle JC, Shields T, Curriero FC, Norris DE. Spatio-temporal heterogeneity of malaria vectors in northern Zambia: implications for vector control. Parasit Vectors 2016; 9:510. [PMID: 27655231 PMCID: PMC5031275 DOI: 10.1186/s13071-016-1786-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 09/01/2016] [Indexed: 11/16/2022] Open
Abstract
Background Despite large reductions in malaria burden across Zambia, some regions continue to experience extremely high malaria transmission. In Nchelenge District, Luapula Province, northern Zambia, almost half the human population carries parasites. Intervention coverage has increased substantially over the past decade, but comprehensive district-wide entomological studies to guide delivery of vector control measures are lacking. This study describes the bionomics and spatio-temporal patterns of malaria vectors in Nchelenge over a two and a half year period, investigates what household factors are associated with high vector densities and determines why vector control may not have been effective in the past to better guide future control efforts. Methods Between April 2012 and September 2014, twenty-seven households from across Nchelenge District were randomly selected for monthly light trap collections of mosquitoes. Anopheline mosquitoes were identified morphologically and molecularly to species. Foraging rates were estimated and sporozoite rates were determined by circumsporozoite ELISAs to calculate annual entomological inoculation rates. Blood feeding rates and host preference were determined by PCR. Zero-inflated negative binomial models measured environmental and household factors associated with mosquito abundance at study households such as season, proximity to the lake, and use of vector control measures. Results The dominant species in Nchelenge was An. funestus (s.s.) with An. gambiae (s.s.) as a secondary vector. Both vectors were found together in large numbers across the district and the combined EIRs of the two vectors exceeded 80 infectious bites per person per annum. An. funestus household densities increased in the dry season whilst An. gambiae surged during the rains. Presence of insecticide treated nets (ITNs) and closed eaves in the houses were found to be associated with fewer numbers of An. gambiae but not An. funestus. There was no association with indoor residual spraying (IRS). Conclusion In Nchelenge, the co-existence of two highly anthropophagic vectors, present throughout the year, is likely to be driving the high malaria transmission evident in the district. The vectors here have been shown to be highly resistant to pyrethroids used for IRS during the study. Vector control interventions in this area would have to be multifaceted and district-wide for effective control of malaria. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1786-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Jennifer C Stevenson
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA. .,Macha Research Trust, P.O. Box 630166, Choma, Zambia.
| | - Jessie Pinchoff
- The W. Harry Feinstone Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Mbanga Muleba
- Tropical Diseases Research Centre Room 727, Ndola Central Hospital, P.O. Box 71769, Ndola, Zambia
| | - James Lupiya
- Tropical Diseases Research Centre Room 727, Ndola Central Hospital, P.O. Box 71769, Ndola, Zambia
| | - Hunter Chilusu
- Tropical Diseases Research Centre Room 727, Ndola Central Hospital, P.O. Box 71769, Ndola, Zambia
| | - Ian Mwelwa
- Tropical Diseases Research Centre Room 727, Ndola Central Hospital, P.O. Box 71769, Ndola, Zambia
| | - David Mbewe
- Tropical Diseases Research Centre Room 727, Ndola Central Hospital, P.O. Box 71769, Ndola, Zambia
| | | | - Christine M Jones
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Mike Chaponda
- Tropical Diseases Research Centre Room 727, Ndola Central Hospital, P.O. Box 71769, Ndola, Zambia
| | - Maureen Coetzee
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Modest Mulenga
- Tropical Diseases Research Centre Room 727, Ndola Central Hospital, P.O. Box 71769, Ndola, Zambia
| | - Julia C Pringle
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Tim Shields
- The W. Harry Feinstone Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Frank C Curriero
- The W. Harry Feinstone Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Douglas E Norris
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | | |
Collapse
|
21
|
Pinchoff J, Chaponda M, Shields TM, Sichivula J, Muleba M, Mulenga M, Kobayashi T, Curriero FC, Moss WJ. Individual and Household Level Risk Factors Associated with Malaria in Nchelenge District, a Region with Perennial Transmission: A Serial Cross-Sectional Study from 2012 to 2015. PLoS One 2016; 11:e0156717. [PMID: 27281028 PMCID: PMC4900528 DOI: 10.1371/journal.pone.0156717] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/18/2016] [Indexed: 11/18/2022] Open
Abstract
Background The scale-up of malaria control interventions has resulted in substantial declines in transmission in some but not all regions of sub-Saharan Africa. Understanding factors associated with persistent malaria transmission despite control efforts may guide targeted interventions to high-risk areas and populations. Methods Household malaria surveys were conducted in Nchelenge District, Luapula Province, in northern Zambia. Structures that appeared to be households were enumerated from a high-resolution satellite image and randomly sampled for enrollment. Households were enrolled into cross-sectional (single visit) or longitudinal (visits every other month) cohorts but analyses were restricted to cross-sectional visits and the first visit to longitudinal households. During study visits, a questionnaire was administered to adults and caretakers of children and a blood sample was collected for a malaria rapid diagnostic test (RDT) from all household residents. Characteristics associated with RDT positivity were analyzed using multi-level models. Results A total of 2,486 individuals residing within 742 households were enrolled between April 2012 and July 2015. Over this period, 51% of participants were RDT positive. Forty-three percent of all RDT positive individuals were between the ages of 5 and 17 years although this age group comprised only 30% of study participants. In a multivariable model, the odds being RDT positive were highest in 5–17 year olds and did not vary by season. Children 5–17 years of age had 8.83 higher odds of being RDT positive compared with those >18 years of age (95% CI: 6.13, 12.71); there was an interaction between age and report of symptoms, with an almost 50% increased odds of report of symptoms with decreasing age category (OR = 1.49; 95% CI 1.11, 2.00). Conclusions Children and adolescents between the ages of 5 and 17 were at the highest risk of malaria infection throughout the year. School-based programs may be effective at targeting this high-risk group.
Collapse
Affiliation(s)
- Jessie Pinchoff
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | | | - Timothy M Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | | | | | | | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Frank C Curriero
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | | |
Collapse
|
22
|
Kanyangarara M, Mamini E, Mharakurwa S, Munyati S, Gwanzura L, Kobayashi T, Shields T, Mullany LC, Mutambu S, Mason PR, Curriero FC, Moss WJ. High-Resolution Plasmodium falciparum Malaria Risk Mapping in Mutasa District, Zimbabwe: Implications for Regaining Control. Am J Trop Med Hyg 2016; 95:141-7. [PMID: 27114294 DOI: 10.4269/ajtmh.15-0865] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/31/2016] [Indexed: 11/07/2022] Open
Abstract
In Zimbabwe, more than half of malaria cases are concentrated in Manicaland Province, where seasonal malaria epidemics occur despite intensified control strategies. The objectives of this study were to develop a prediction model based on environmental risk factors and obtain seasonal malaria risk maps for Mutasa District, one of the worst affected districts in Manicaland Province. From October 2012 to September 2015, 483 households were surveyed, and 104 individuals residing within 69 households had positive rapid diagnostic test results. Logistic regression was used to model the probability of household positivity as a function of the environmental covariates extracted from high-resolution remote sensing data sources. Model predictions and prediction standard errors were generated for the rainy and dry seasons. The resulting maps predicted elevated risk during the rainy season, particularly in low-lying areas bordering Mozambique. In contrast, the risk of malaria was low across the study area during the dry season with foci of malaria risk scattered along the northern and western peripheries of the study area. These findings underscore the need for strong cross-border malaria control initiatives to complement country-specific interventions.
Collapse
Affiliation(s)
- Mufaro Kanyangarara
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland.
| | - Edmore Mamini
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | | | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Department of Medical Laboratory Sciences, College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Timothy Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Luke C Mullany
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Susan Mutambu
- National Institute of Health Research, Harare, Zimbabwe
| | - Peter R Mason
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Frank C Curriero
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | | | | |
Collapse
|
23
|
Kanyangarara M, Mamini E, Mharakurwa S, Munyati S, Gwanzura L, Kobayashi T, Shields T, Mullany LC, Mutambu S, Mason PR, Curriero FC, Moss WJ. Reduction in Malaria Incidence following Indoor Residual Spraying with Actellic 300 CS in a Setting with Pyrethroid Resistance: Mutasa District, Zimbabwe. PLoS One 2016; 11:e0151971. [PMID: 27018893 PMCID: PMC4809594 DOI: 10.1371/journal.pone.0151971] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/07/2016] [Indexed: 12/04/2022] Open
Abstract
Background More than half of malaria cases in Zimbabwe are concentrated in Manicaland Province, where seasonal malaria epidemics occur despite intensified control strategies. Recently, high levels of pyrethroid and carbamate resistance were detected in Anopheles funestus, the major malaria vector in eastern Zimbabwe. In response, a single round of indoor residual spraying (IRS) using pirimiphos-methyl (an organophosphate) was implemented in four high burden districts of Manicaland Province from November 1, 2014 to December 19, 2014. The objective of this study was to evaluate the effect of this programmatic switch in insecticides on malaria morbidity reported from health care facilities in Mutasa District, one of the worst affected districts in Manicaland Province. Methods The number of weekly malaria cases for each health facility 24 months prior to the 2014 IRS campaign and in the subsequent high transmission season were obtained from passive case surveillance. Environmental variables were extracted from remote-sensing data sources and linked to each health care facility. Negative binomial regression was used to model the weekly number of malaria cases, adjusted for seasonality and environmental variables. Results From December 2012 to May 2015, 124,206 malaria cases were reported from 42 health care facilities in Mutasa District. Based on a higher burden of malaria, 20 out of 31 municipal wards were sprayed in the district. Overall, 87.3% of target structures were sprayed and 92.1% of the target population protected. During the 6 months after the 2014 IRS campaign, a period when transmission would have otherwise peaked, the incidence of malaria was 38% lower than the preceding 24 months at health facilities in the sprayed wards. Conclusions Pirimiphos-methyl had a measurable impact on malaria incidence and is an effective insecticide for the control of An. funestus in eastern Zimbabwe.
Collapse
Affiliation(s)
- Mufaro Kanyangarara
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
| | - Edmore Mamini
- Biomedical Research Training Institute, Harare, Zimbabwe
| | | | - Shungu Munyati
- Biomedical Research Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research Training Institute, Harare, Zimbabwe
- Department of Medical Laboratory Sciences, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Timothy Shields
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Luke C. Mullany
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Susan Mutambu
- National Institute of Health Research, Harare, Zimbabwe
| | - Peter R. Mason
- Biomedical Research Training Institute, Harare, Zimbabwe
| | - Frank C. Curriero
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - William J. Moss
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | | |
Collapse
|