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Collins KA, Ouedraogo A, Guelbeogo WM, Soulama I, Ouattara MS, Sombie S, Ouedraogo N, Coulibaly AS, Nombre A, Lanke K, Ramjith J, Awandu SS, Serme SS, Henry N, Stone W, Ouedraogo IN, Diarra A, Holden TM, Sirima SB, Bradley J, Soremekun S, Selvaraj P, Gerardin J, Drakeley C, Bousema T, Tiono AB. Effect of weekly fever-screening and treatment and monthly RDT testing and treatment on the infectious reservoir of malaria parasites in Burkina Faso: a cluster-randomised trial. THE LANCET. MICROBE 2024; 5:100891. [PMID: 39068937 DOI: 10.1016/s2666-5247(24)00114-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 04/08/2024] [Accepted: 04/24/2024] [Indexed: 07/30/2024]
Abstract
BACKGROUND The majority of Plasmodium spp infections in endemic countries are asymptomatic and a source of onward transmission to mosquitoes. We aimed to examine whether Plasmodium falciparum transmission and malaria burden could be reduced by improving early detection and treatment of infections with active screening approaches. METHODS In this 18-month cluster randomised study in Sapone, Burkina Faso, households were enrolled and randomly assigned (1:1:1) to one of three groups: group 1 (control) received standard of care only, group 2 received active weekly, at home, fever screening by a community health worker regardless of symptoms, participants with a fever received a rapid diagnostic test (RDT) and treatment if RDT positive, and group 3 received active weekly fever screening (as in group 2) plus a monthly RDT regardless of symptoms, and treatment if RDT positive. Eligible households had a minimum of three eligible residents, one in each age group (<5 years, 5-15 years, and >15 years). The primary outcome was parasite prevalence by quantitative PCR (qPCR) in the end-of-study cross-sectional survey. Secondary outcomes included parasite and gametocyte prevalence and density in all three end-of-season cross-sectional surveys, incidence of infection, and the transmissibility of infections to mosquitoes. This trial was registered at ClinicalTrials.gov (NCT03705624) and is completed. FINDINGS A total of 906 individuals from 181 households were enrolled during two phases, and participated in the study. 412 individuals were enrolled between Aug 9 and 17, 2018, and participated in phase 1 and 494 individuals were enrolled between Jan 10 and 31, 2019, in phase 2. In the end-of-study cross-sectional survey (conducted between Jan 13 and 21, 2020), Pfalciparum prevalence by qPCR was significantly lower in group 3 (29·26%; 79 of 270), but not in group 2 (45·66%; 121 of 265), when compared with group 1 (48·72%; 133 of 273; risk ratio 0·65 [95% CI 0·52-0·81]; p=0·0001). Total parasite and gametocyte prevalence and density were also significantly lower in group 3 in all surveys. The largest differences were seen at the end of the dry season, with gametocyte prevalence 78·4% and predicted transmission potential 98·2% lower in group 3 than in group 1. INTERPRETATION Active monthly RDT testing and treatment can reduce parasite carriage and the infectious reservoir of P falciparum to less than 2% when used during the dry season. This insight might inform approaches for malaria control and elimination. FUNDING Bill & Melinda Gates Foundation, European Research Council, and The Netherlands Organization for Scientific Research.
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Affiliation(s)
- Katharine A Collins
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Alphonse Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | - Issiaka Soulama
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Maurice S Ouattara
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Salif Sombie
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Nicolas Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Aboubacar S Coulibaly
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Apollinaire Nombre
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Jordache Ramjith
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Shehu S Awandu
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Samuel S Serme
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Noelie Henry
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Will Stone
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Issa N Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Amidou Diarra
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Tobias M Holden
- Department of Preventive Medicine and Institute for Global Health, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | | | - John Bradley
- International Statistics and Epidemiology Group, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Seyi Soremekun
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Jaline Gerardin
- Department of Preventive Medicine and Institute for Global Health, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Institute for Disease Modeling, Bellevue, WA, USA
| | - Chris Drakeley
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands.
| | - Alfred B Tiono
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
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Banegas S, Escobar D, Pinto A, Moncada M, Matamoros G, Valdivia HO, Reyes A, Fontecha G. Asymptomatic Malaria Reservoirs in Honduras: A Challenge for Elimination. Pathogens 2024; 13:541. [PMID: 39057768 PMCID: PMC11280452 DOI: 10.3390/pathogens13070541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/17/2024] [Accepted: 06/21/2024] [Indexed: 07/28/2024] Open
Abstract
BACKGROUND Efforts on a global scale for combating malaria have achieved substantial progress over the past twenty years. Two Central American nations have accomplished their goal of eliminating malaria: El Salvador and Belize. Honduras has decreased the incidence of malaria and now reports fewer than 4000 malaria cases annually, aspiring to reach elimination by 2030. To accomplish this goal, it is essential to assess the existing strategies employed for malaria control and to address the task of incorporating novel intervention strategies to identify asymptomatic reservoirs. METHODS A survey for detecting asymptomatic cases was carried out in the community of Kaukira, in Gracias a Dios, Honduras, focusing on malaria transmission during 2023. Asymptomatic community members were recruited as participants, malaria screening was performed through a rapid diagnostic test in situ, and a blood sample was collected on filter paper. Highly sensitive molecular assays based on photo-induced electron transfer PCR (PET-PCR) were performed to detect the two species of Plasmodium circulating in Honduras: Plasmodium vivax and Plasmodium falciparum. In addition, the identification of the parasite species was verified by amplifying three genetic markers (Pvmsp3α, Pvmsp3ß, and Pfmsp1). RESULTS A total of 138 participants were recruited, mostly adult women. All individuals tested negative on the rapid diagnostic test. Positive results for malaria were detected by PET-PCR in 17 samples (12.3%). Most samples (12 out of 17) were amplified with a Ct value between 37 and 42, indicating very low parasitemias. Out of the 17 samples, 16 of them also showed amplification in the species assays. There were nine cases of P. falciparum infections and seven cases of P. vivax infections that were further confirmed by nested PCR (nPCR) of Pvmsp3 and Pfmsp1. Parasitemias ranged from 100 p/μL to less than 0.25 p/μL. One sample showed mixed infection. CONCLUSIONS The existence of asymptomatic malaria reservoirs in Honduras can contribute to disease transmission and pose a challenge that may hinder elimination efforts, requiring public health authorities to modify surveillance strategies to identify the disease and treat this population accordingly.
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Affiliation(s)
- Sharon Banegas
- Instituto de Investigaciones en Microbiología, Facultad de Ciencias, Universidad Nacional Autónoma de Honduras, Tegucigalpa 11101, Honduras
| | - Denis Escobar
- Instituto de Investigaciones en Microbiología, Facultad de Ciencias, Universidad Nacional Autónoma de Honduras, Tegucigalpa 11101, Honduras
| | - Alejandra Pinto
- Instituto de Investigaciones en Microbiología, Facultad de Ciencias, Universidad Nacional Autónoma de Honduras, Tegucigalpa 11101, Honduras
| | - Marcela Moncada
- Instituto de Investigaciones en Microbiología, Facultad de Ciencias, Universidad Nacional Autónoma de Honduras, Tegucigalpa 11101, Honduras
| | - Gabriela Matamoros
- Instituto de Investigaciones en Microbiología, Facultad de Ciencias, Universidad Nacional Autónoma de Honduras, Tegucigalpa 11101, Honduras
| | - Hugo O. Valdivia
- Department of Parasitology, U.S. Naval Medical Research Unit South (NAMRU SOUTH), Lima 07006, Peru
| | - Allan Reyes
- Unidad de Entomología, Región Sanitaria de Gracias a Dios, Secretaría de Salud de Honduras, Puerto Lempira 33101, Gracias a Dios, Honduras
| | - Gustavo Fontecha
- Instituto de Investigaciones en Microbiología, Facultad de Ciencias, Universidad Nacional Autónoma de Honduras, Tegucigalpa 11101, Honduras
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Bhamani B, Martí Coma-Cros E, Tusell M, Mithi V, Serra-Casas E, Williams NA, Lindblade KA, Allen KC. Mass Testing and Treatment to Accelerate Malaria Elimination: A Systematic Review and Meta-Analysis. Am J Trop Med Hyg 2024; 110:44-53. [PMID: 38471168 PMCID: PMC10993795 DOI: 10.4269/ajtmh.23-0127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 01/17/2024] [Indexed: 03/14/2024] Open
Abstract
In regions where malaria transmission persists, the implementation of approaches aimed at eliminating parasites from the population can effectively decrease both burden of disease and transmission of infection. Thus, mass strategies that target symptomatic and asymptomatic infections at the same time may help countries to reduce transmission. This systematic review assessed the potential benefits and harms of mass testing and treatment (MTaT) to reduce malaria transmission. Searches were conducted in March 2021 and updated in April 2022 and included cluster-randomized controlled trials (cRCTs) as well as nonrandomized studies (NRSs) using malaria infection incidence, clinical malaria incidence, or prevalence as outcomes. The risk of bias was assessed with Cochrane's risk of bias (RoB2) tool and Risk of Bias Tool in Nonrandomized Studies - of Interventions (ROBINS-I), and the certainty of evidence (CoE) was graded for each outcome. Of 4,462 citations identified, seven studies (four cRCTs and three NRSs) contributed outcome data. The analysis revealed that MTaT did not reduce the incidence (risk ratio [RR]: 0.95, 95% CI: 0.87-1.04; 1,181 participants; moderate CoE) or prevalence (RR: 0.83, 95% CI: 0.67-1.01; 7,522 participants; moderate CoE) of malaria infection but resulted in a small reduction in clinical malaria (RR: 0.82; 95% CI: 0.70-0.95; 334,944 participants; moderate CoE). Three studies contributing data on contextual factors concluded that MTaT is an acceptable, feasible, and cost-effective intervention. Mathematical modeling analyses (n = 10) suggested that MTaT effectiveness depends on the baseline transmission level, diagnostic test performance, number of rounds, and other co-interventions. Based on the limited evidence available, MTaT has little to no impact on reducing malaria transmission.
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Affiliation(s)
- Beena Bhamani
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
| | - Elisabet Martí Coma-Cros
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
| | - Maria Tusell
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
| | - Vita Mithi
- Armref Data for Action in Public Health Research Consultancy, Mzuzu, Malawi
- Society for Research on Nicotine and Tobacco-Genetics and Omics Network, Madison, Wisconsin
- Leaders of Africa Institute, Baltimore, Maryland
| | - Elisa Serra-Casas
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
| | - Nana Aba Williams
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
| | - Kim A. Lindblade
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Koya C. Allen
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
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Newby G, Cotter C, Roh ME, Harvard K, Bennett A, Hwang J, Chitnis N, Fine S, Stresman G, Chen I, Gosling R, Hsiang MS. Testing and treatment for malaria elimination: a systematic review. Malar J 2023; 22:254. [PMID: 37661286 PMCID: PMC10476355 DOI: 10.1186/s12936-023-04670-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/07/2023] [Indexed: 09/05/2023] Open
Abstract
BACKGROUND Global interest in malaria elimination has prompted research on active test and treat (TaT) strategies. METHODS A systematic review and meta-analysis were conducted to assess the effectiveness of TaT strategies to reduce malaria transmission. RESULTS A total of 72 empirical research and 24 modelling studies were identified, mainly focused on proactive mass TaT (MTaT) and reactive case detection (RACD) in higher and lower transmission settings, respectively. Ten intervention studies compared MTaT to no MTaT and the evidence for impact on malaria incidence was weak. No intervention studies compared RACD to no RACD. Compared to passive case detection (PCD) alone, PCD + RACD using standard diagnostics increased infection detection 52.7% and 11.3% in low and very low transmission settings, respectively. Using molecular methods increased this detection of infections by 1.4- and 1.1-fold, respectively. CONCLUSION Results suggest MTaT is not effective for reducing transmission. By increasing case detection, surveillance data provided by RACD may indirectly reduce transmission by informing coordinated responses of intervention targeting.
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Affiliation(s)
- Gretchen Newby
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
| | - Chris Cotter
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
- Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
| | - Michelle E Roh
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA
| | - Kelly Harvard
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
| | - Adam Bennett
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA
- PATH, Seattle, WA, USA
| | - Jimee Hwang
- Malaria Branch, Centers for Disease Control and Prevention, U.S. President's Malaria Initiative, Atlanta, GA, USA
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Sydney Fine
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
| | - Gillian Stresman
- College of Public Health, University of South Florida, Tampa, FL, USA
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Ingrid Chen
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA
| | - Roly Gosling
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA.
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA.
- Department of Pediatrics, UCSF, San Francisco, CA, USA.
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Bertozzi-Villa A, Bever CA, Gerardin J, Proctor JL, Wu M, Harding D, Hollingsworth TD, Bhatt S, Gething PW. An archetypes approach to malaria intervention impact mapping: a new framework and example application. Malar J 2023; 22:138. [PMID: 37101269 PMCID: PMC10131392 DOI: 10.1186/s12936-023-04535-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 03/15/2023] [Indexed: 04/28/2023] Open
Abstract
BACKGROUND As both mechanistic and geospatial malaria modeling methods become more integrated into malaria policy decisions, there is increasing demand for strategies that combine these two methods. This paper introduces a novel archetypes-based methodology for generating high-resolution intervention impact maps based on mechanistic model simulations. An example configuration of the framework is described and explored. METHODS First, dimensionality reduction and clustering techniques were applied to rasterized geospatial environmental and mosquito covariates to find archetypal malaria transmission patterns. Next, mechanistic models were run on a representative site from each archetype to assess intervention impact. Finally, these mechanistic results were reprojected onto each pixel to generate full maps of intervention impact. The example configuration used ERA5 and Malaria Atlas Project covariates, singular value decomposition, k-means clustering, and the Institute for Disease Modeling's EMOD model to explore a range of three-year malaria interventions primarily focused on vector control and case management. RESULTS Rainfall, temperature, and mosquito abundance layers were clustered into ten transmission archetypes with distinct properties. Example intervention impact curves and maps highlighted archetype-specific variation in efficacy of vector control interventions. A sensitivity analysis showed that the procedure for selecting representative sites to simulate worked well in all but one archetype. CONCLUSION This paper introduces a novel methodology which combines the richness of spatiotemporal mapping with the rigor of mechanistic modeling to create a multi-purpose infrastructure for answering a broad range of important questions in the malaria policy space. It is flexible and adaptable to a range of input covariates, mechanistic models, and mapping strategies and can be adapted to the modelers' setting of choice.
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Affiliation(s)
- Amelia Bertozzi-Villa
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA.
- Malaria Atlas Project, Telethon Kids Institute, Perth, Australia.
- Big Data Institute, Nuffield Department of Medicine, Oxford University, Oxford, UK.
| | - Caitlin A Bever
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA
| | - Jaline Gerardin
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, USA
| | - Joshua L Proctor
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA
| | - Meikang Wu
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA
| | - Dennis Harding
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA
| | | | - Samir Bhatt
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College, London, UK
- Section of Epidemiology, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Peter W Gething
- Malaria Atlas Project, Telethon Kids Institute, Perth, Australia
- Curtin University, Perth, Australia
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Ahorlu CS, Ndong IC, Okyere D, Mensah BA, Chu CE, Enos JY, Abuaku B. The Effect of Mass Testing, Treatment and Tracking on the Prevalence of Febrile Illness in Children under 15 in Ghana. Pathogens 2022; 11:pathogens11101118. [PMID: 36297175 PMCID: PMC9609179 DOI: 10.3390/pathogens11101118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/16/2022] [Accepted: 09/24/2022] [Indexed: 11/18/2022] Open
Abstract
Background: Malaria remains a serious threat to children under 15 years of age in sub-Sahara Africa. Mass testing, treatment and tracking (MTTT) of malaria has been reported to reduce parasite load significantly. However, the impact of MTTT on the prevalence of febrile illnesses in children under 15 is not yet clear. This study explores the impact of MTTT complemented by prompt home-based management of malaria on febrile illnesses and their treatment in children under 15 years old. Methods: A cohort of 460 children under 15 years were recruited from the Pakro subdistrict in Ghana during a community-wide implementation of a quarterly MTTT intervention. The MTTT implementation involved testing all household members for malaria using RDTs, and positive cases were treated with Artemisinin-based combination therapy (ACT). Febrile illnesses among this cohort in the two weeks prior to the prevalence survey at baseline and endline were recorded to constitute date for analysis. Results: The prevalence of febrile illnesses, such chills, convulsion, fever, diarrhoea, headache, vomit, cough/rashes or stomachache, etc., were recorded). Asymptomatic parasitaemia prevalence at baseline was 53.3%, which dropped to 44.1% at evaluation. An overall decrease in the parasitaemia prevalence of 33.0% (OR = 0.67, CI = 0.50, 0.89) was observed at evaluation compared to baseline after adjusting for age, ITN use and temperature. A 67% decrease in severe anaemia cases (Hb < 7) was observed at evaluation. Conclusion: Our findings suggest that implementing MTTT complemented by home-based timely management of malaria does not only reduce febrile illnesses and for that matter malaria prevalence, but could also reduce severe anaemia in children under 15 years old.
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Affiliation(s)
- Collins Stephen Ahorlu
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra P.O. Box LG 581, Ghana
- Correspondence:
| | - Ignatius Cheng Ndong
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra P.O. Box LG 581, Ghana
- Department of Biochemistry, Faculty of Science, Catholic University of Cameroon, Bamenda P.O. Box 572, Cameroon
| | - Daniel Okyere
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra P.O. Box LG 581, Ghana
| | - Benedicta A. Mensah
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra P.O. Box LG 581, Ghana
| | - Chuo Ennestine Chu
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra P.O. Box LG 581, Ghana
- Department of Biochemistry, Faculty of Science, Catholic University of Cameroon, Bamenda P.O. Box 572, Cameroon
| | - Juliana Y. Enos
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra P.O. Box LG 581, Ghana
| | - Benjamin Abuaku
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra P.O. Box LG 581, Ghana
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Nundu SS, Simpson SV, Arima H, Muyembe JJ, Mita T, Ahuka S, Yamamoto T. It Is Time to Strengthen the Malaria Control Policy of the Democratic Republic of Congo and Include Schools and School-Age Children in Malaria Control Measures. Pathogens 2022; 11:729. [PMID: 35889975 PMCID: PMC9315856 DOI: 10.3390/pathogens11070729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 06/22/2022] [Accepted: 06/24/2022] [Indexed: 02/04/2023] Open
Abstract
Despite a decade of sustained malaria control, malaria remains a serious public health problem in the Democratic Republic of Congo (DRC). Children under five years of age and school-age children aged 5-15 years remain at high risk of symptomatic and asymptomatic malaria infections. The World Health Organization's malaria control, elimination, and eradication recommendations are still only partially implemented in DRC. For better malaria control and eventual elimination, the integration of all individuals into the national malaria control programme will strengthen malaria control and elimination strategies in the country. Thus, inclusion of schools and school-age children in DRC malaria control interventions is needed.
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Affiliation(s)
- Sabin S. Nundu
- Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo; (J.-J.M.); (S.A.)
- Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan; (S.V.S.); (T.Y.)
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan;
| | - Shirley V. Simpson
- Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan; (S.V.S.); (T.Y.)
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan;
| | - Hiroaki Arima
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan;
| | - Jean-Jacques Muyembe
- Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo; (J.-J.M.); (S.A.)
| | - Toshihiro Mita
- Department of Tropical Medicine and Parasitology, Faculty of Medicine, Juntendo University, Tokyo 113-8421, Japan;
| | - Steve Ahuka
- Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo; (J.-J.M.); (S.A.)
| | - Taro Yamamoto
- Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan; (S.V.S.); (T.Y.)
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan;
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Yukich JO, Lindblade K, Kolaczinski J. Receptivity to malaria: meaning and measurement. Malar J 2022; 21:145. [PMID: 35527264 PMCID: PMC9080212 DOI: 10.1186/s12936-022-04155-0] [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: 05/12/2021] [Accepted: 04/07/2022] [Indexed: 01/13/2023] Open
Abstract
"Receptivity" to malaria is a construct developed during the Global Malaria Eradication Programme (GMEP) era. It has been defined in varied ways and no consistent, quantitative definition has emerged over the intervening decades. Despite the lack of consistency in defining this construct, the idea that some areas are more likely to sustain malaria transmission than others has remained important in decision-making in malaria control, planning for malaria elimination and guiding activities during the prevention of re-establishment (POR) period. This manuscript examines current advances in methods of measurement. In the context of a decades long decline in global malaria transmission and an increasing number of countries seeking to eliminate malaria, understanding and measuring malaria receptivity has acquired new relevance.
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Affiliation(s)
- Joshua O. Yukich
- grid.265219.b0000 0001 2217 8588Department of Tropical Medicine, Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA USA
| | - Kim Lindblade
- grid.3575.40000000121633745Global Malaria Programme, World Health Organization, Geneva, CH USA
| | - Jan Kolaczinski
- grid.3575.40000000121633745Global Malaria Programme, World Health Organization, Geneva, CH USA
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Pradhan MM, Pradhan S, Dutta A, Shah NK, Valecha N, Joshi PL, Pradhan K, Grewal Daumerie P, Banerji J, Duparc S, Mendis K, Sharma SK, Murugasampillay S, Anvikar AR. Impact of the malaria comprehensive case management programme in Odisha, India. PLoS One 2022; 17:e0265352. [PMID: 35324920 PMCID: PMC8947122 DOI: 10.1371/journal.pone.0265352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 02/28/2022] [Indexed: 11/19/2022] Open
Abstract
Background
The Comprehensive Case Management Project (CCMP), was a collaborative implementation research initiative to strengthen malaria early detection and complete treatment in Odisha State, India.
Methods
A two-arm quasi-experimental design was deployed across four districts in Odisha, representing a range of malaria endemicity: Bolangir (low), Dhenkanal (moderate), Angul (high), and Kandhamal (hyper). In each district, a control block received routine malaria control measures, whereas a CCMP block received a range of interventions to intensify surveillance, diagnosis, and case management. Impact was evaluated by difference-in-difference (DID) analysis and interrupted time-series (ITS) analysis of monthly blood examination rate (MBER) and monthly parasite index (MPI) over three phases: phase 1 pre-CCMP (2009–2012) phase 2 CCMP intervention (2013–2015), and phase 3 post-CCMP (2016–2017).
Results
During CCMP implementation, adjusting for control blocks, DID and ITS analysis indicated a 25% increase in MBER and a 96% increase in MPI, followed by a –47% decline in MPI post-CCMP, though MBER was maintained. Level changes in MPI between phases 1 and 2 were most marked in Dhenkanal and Angul with increases of 976% and 287%, respectively, but declines in Bolangir (−57%) and Kandhamal (−22%). Between phase 2 and phase 3, despite the MBER remaining relatively constant, substantial decreases in MPI were observed in Dhenkanal (−78%), and Angul (−59%), with a more modest decline in Bolangir (−13%), and an increase in Kandhamal (14%).
Conclusions
Overall, CCMP improved malaria early detection and treatment through the enhancement of the existing network of malaria services which positively impacted case incidence in three districts. In Kandhamal, which is hyperendemic, the impact was not evident. However, in Dhenkanal and Angul, areas of moderate-to-high malaria endemicity, CCMP interventions precipitated a dramatic increase in case detection and a subsequent decline in malaria incidence, particularly in previously difficult-to-reach communities.
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Affiliation(s)
- Madan M. Pradhan
- National Vector Borne Disease Control Programme, Government of Odisha, Bhubaneswar, India
- * E-mail:
| | - Sreya Pradhan
- National Vector Borne Disease Control Programme, Government of Odisha, Bhubaneswar, India
| | - Ambarish Dutta
- Indian Institute of Public Health, Bhubaneswar, India
- Kalinga Institute of Industrial Technology, Deemed to be University, Bhubaneswar, India
| | - Naman K. Shah
- University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Neena Valecha
- National Institute of Malaria Research, New Delhi, India
| | - Pyare L. Joshi
- Independent Malariologist, Gallup, Washington, D.C., United States of America
| | | | | | - Jaya Banerji
- Medicines for Malaria Venture, Geneva, Switzerland
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Millar J, Toh KB, Valle D. To screen or not to screen: an interactive framework for comparing costs of mass malaria treatment interventions. BMC Med 2020; 18:149. [PMID: 32552743 PMCID: PMC7304173 DOI: 10.1186/s12916-020-01609-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 04/28/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Mass drug administration and mass-screen-and-treat interventions have been used to interrupt malaria transmission and reduce burden in sub-Saharan Africa. Determining which strategy will reduce costs is an important challenge for implementers; however, model-based simulations and field studies have yet to develop consensus guidelines. Moreover, there is often no way for decision-makers to directly interact with these data and/or models, incorporate local knowledge and expertise, and re-fit parameters to guide their specific goals. METHODS We propose a general framework for comparing costs associated with mass drug administrations and mass screen and treat based on the possible outcomes of each intervention and the costs associated with each outcome. We then used publicly available data from six countries in western Africa to develop spatial-explicit probabilistic models to estimate intervention costs based on baseline malaria prevalence, diagnostic performance, and sociodemographic factors (age and urbanicity). In addition to comparing specific scenarios, we also develop interactive web applications which allow managers to select data sources and model parameters, and directly input their own cost values. RESULTS The regional-level models revealed substantial spatial heterogeneity in malaria prevalence and diagnostic test sensitivity and specificity, indicating that a "one-size-fits-all" approach is unlikely to maximize resource allocation. For instance, urban communities in Burkina Faso typically had lower prevalence rates compared to rural communities (0.151 versus 0.383, respectively) as well as lower diagnostic sensitivity (0.699 versus 0.862, respectively); however, there was still substantial regional variation. Adjusting the cost associated with false negative diagnostic results to included additional costs, such as delayed treated and potential lost wages, undermined the overall costs associated with MSAT. CONCLUSIONS The observed spatial variability and dependence on specified cost values support not only the need for location-specific intervention approaches but also the need to move beyond standard modeling approaches and towards interactive tools which allow implementers to engage directly with data and models. We believe that the framework demonstrated in this article will help connect modeling efforts and stakeholders in order to promote data-driven decision-making for the effective management of malaria, as well as other diseases.
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Affiliation(s)
- Justin Millar
- School of Forest Resources and Conservation, University of Florida, Gainesville, USA.
- Emerging Pathogens Institute, University of Florida, Gainesville, USA.
| | - Kok Ben Toh
- Emerging Pathogens Institute, University of Florida, Gainesville, USA
- School of Natural Resources and Environment, University of Florida, Gainesville, USA
| | - Denis Valle
- School of Forest Resources and Conservation, University of Florida, Gainesville, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, USA
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Ndong IC, Okyere D, Enos JY, Mensah BA, Nyarko A, Abuaku B, Amambua-Ngwa A, Merle CSC, Koram KA, Ahorlu CS. Prevalence of asymptomatic malaria parasitaemia following mass testing and treatment in Pakro sub-district of Ghana. BMC Public Health 2019; 19:1622. [PMID: 31795981 PMCID: PMC6889629 DOI: 10.1186/s12889-019-7986-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 11/21/2019] [Indexed: 11/22/2022] Open
Abstract
Background Global efforts to scale-up malaria control interventions are gaining steam. These include the use of Long-Lasting Insecticide Nets, Indoor Residual Spraying, Intermittent Preventive Treatment and Test, Treat and Track. Despite these, the drive for malaria elimination is far from being realistic in endemic communities in Africa. This is partly due to the fact that asymptomatic parasite carriage, not specifically targeted by most interventions, remains the bedrock that fuels transmission. This has led to mass testing, treatment and tracking (MTTT) as an alternative strategy to target asymptomatic individuals. We report the impact of MTTT on the prevalence of asymptomatic malaria parasitaemia over a one-year period in Ghana, hypothesizing that implementing MTTT could reduce the rate of asymptomatic parasitaemia. Methods A population of about 5000 individuals in seven communities in the Pakro sub-district of Ghana participated in this study. A register was developed for each community following a census. MTTT engaged trained community-based health volunteers who conducted house-to-house testing using RDTs every 4 months and treated positive cases with Artemisinin–based Combination Therapy. Between interventions, community-based management of malaria was implemented for symptomatic cases. Results MTTT Coverage was 98.8% in July 2017 and 79.3% in July 2018. Of those tested, asymptomatic infection with malaria parasites reduced from 36.3% (1795/4941) in July 2017 to 32.9% (1303/3966) in July 2018 (p = 0.001). Prevalence of asymptomatic parasitaemia among children under 15 years declined from 52.6% (1043/1984) in July 2017 to 47.5% (820/1728) in July 2018 (p = 0.002). Implementing MTTT significantly reduced asymptomatic parasitaemia by 24% from July 2017 to July 2018 after adjusting for age, ITN use and axillary temperature (OR = 0.76, CI = 0.67, 0.85 p ≤ 0.001). Conclusion This study has demonstrated that implementing MTTT is feasible and could reduce the prevalence of asymptomatic malaria parasitaemia in children under 15 years of age. Furthermore, the use of community-based health volunteers could ensure high coverage at lower cost of implementation. Trial registration NCT04167566, Date 14/11/2019. Retrospective registration.
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Affiliation(s)
- Ignatius Cheng Ndong
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana. .,Department of Biochemistry, Faculty of Science, Catholic University of Cameroon, Bamenda, Cameroon.
| | - Daniel Okyere
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Juliana Yartey Enos
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Benedicta A Mensah
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Alexander Nyarko
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Benjamin Abuaku
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit, The Gambia at London School of Hygiene and Tropical Medicine, Serrekunda, Gambia
| | - Corinne Simone C Merle
- Special Programme for Research & Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
| | - Kwadwo Ansah Koram
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Collins Stephen Ahorlu
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
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12
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Gerardin J, Bertozzi-Villa A, Eckhoff PA, Wenger EA. Impact of mass drug administration campaigns depends on interaction with seasonal human movement. Int Health 2019; 10:252-257. [PMID: 29635471 PMCID: PMC6031018 DOI: 10.1093/inthealth/ihy025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 03/06/2018] [Indexed: 11/19/2022] Open
Abstract
Background Mass drug administration (MDA) is a control and elimination tool for treating infectious diseases. For malaria, it is widely accepted that conducting MDA during the dry season results in the best outcomes. However, seasonal movement of populations into and out of MDA target areas is common in many places and could potentially fundamentally limit the ability of MDA campaigns to achieve elimination. Methods A mathematical model was used to simulate malaria transmission in two villages connected to a high-risk area into and out of which 10% of villagers traveled seasonally. MDA was given only in the villages. Prevalence reduction under various possible timings of MDA and seasonal travel was predicted. Results MDA is most successful when distributed outside the traveling season and during the village low-transmission season. MDA is least successful when distributed during the traveling season and when traveling overlaps with the peak transmission season in the high-risk area. Mistiming MDA relative to seasonal travel resulted in much poorer outcomes than mistiming MDA relative to the peak transmission season within the villages. Conclusions Seasonal movement patterns of high-risk groups should be taken into consideration when selecting the optimum timing of MDA campaigns.
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Smith NR, Trauer JM, Gambhir M, Richards JS, Maude RJ, Keith JM, Flegg JA. Agent-based models of malaria transmission: a systematic review. Malar J 2018; 17:299. [PMID: 30119664 PMCID: PMC6098619 DOI: 10.1186/s12936-018-2442-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 08/04/2018] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Much of the extensive research regarding transmission of malaria is underpinned by mathematical modelling. Compartmental models, which focus on interactions and transitions between population strata, have been a mainstay of such modelling for more than a century. However, modellers are increasingly adopting agent-based approaches, which model hosts, vectors and/or their interactions on an individual level. One reason for the increasing popularity of such models is their potential to provide enhanced realism by allowing system-level behaviours to emerge as a consequence of accumulated individual-level interactions, as occurs in real populations. METHODS A systematic review of 90 articles published between 1998 and May 2018 was performed, characterizing agent-based models (ABMs) relevant to malaria transmission. The review provides an overview of approaches used to date, determines the advantages of these approaches, and proposes ideas for progressing the field. RESULTS The rationale for ABM use over other modelling approaches centres around three points: the need to accurately represent increased stochasticity in low-transmission settings; the benefits of high-resolution spatial simulations; and heterogeneities in drug and vaccine efficacies due to individual patient characteristics. The success of these approaches provides avenues for further exploration of agent-based techniques for modelling malaria transmission. Potential extensions include varying elimination strategies across spatial landscapes, extending the size of spatial models, incorporating human movement dynamics, and developing increasingly comprehensive parameter estimation and optimization techniques. CONCLUSION Collectively, the literature covers an extensive array of topics, including the full spectrum of transmission and intervention regimes. Bringing these elements together under a common framework may enhance knowledge of, and guide policies towards, malaria elimination. However, because of the diversity of available models, endorsing a standardized approach to ABM implementation may not be possible. Instead it is recommended that model frameworks be contextually appropriate and sufficiently described. One key recommendation is to develop enhanced parameter estimation and optimization techniques. Extensions of current techniques will provide the robust results required to enhance current elimination efforts.
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Affiliation(s)
- Neal R Smith
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.
| | - James M Trauer
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia
| | - Manoj Gambhir
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia
- IBM Research Australia, Melbourne, Australia
| | - Jack S Richards
- Life Sciences, Burnet Institute, Melbourne, Australia
- Department of Medicine, University of Melbourne, Parkville, Australia
- Department of Infectious Diseases, Monash University, Melbourne, Australia
| | - 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
| | - Jonathan M Keith
- School of Mathematical Sciences, Monash University, Clayton, Australia
| | - Jennifer A Flegg
- School of Mathematics and Statistics, University of Melbourne, Parkville, Australia
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Abstract
This paper summarises key advances and priorities since the 2011 presentation of the Malaria Eradication Research Agenda (malERA), with a focus on the combinations of intervention tools and strategies for elimination and their evaluation using modelling approaches. With an increasing number of countries embarking on malaria elimination programmes, national and local decisions to select combinations of tools and deployment strategies directed at malaria elimination must address rapidly changing transmission patterns across diverse geographic areas. However, not all of these approaches can be systematically evaluated in the field. Thus, there is potential for modelling to investigate appropriate 'packages' of combined interventions that include various forms of vector control, case management, surveillance, and population-based approaches for different settings, particularly at lower transmission levels. Modelling can help prioritise which intervention packages should be tested in field studies, suggest which intervention package should be used at a particular level or stratum of transmission intensity, estimate the risk of resurgence when scaling down specific interventions after local transmission is interrupted, and evaluate the risk and impact of parasite drug resistance and vector insecticide resistance. However, modelling intervention package deployment against a heterogeneous transmission background is a challenge. Further validation of malaria models should be pursued through an iterative process, whereby field data collected with the deployment of intervention packages is used to refine models and make them progressively more relevant for assessing and predicting elimination outcomes.
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15
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Brady OJ, Slater HC, Pemberton-Ross P, Wenger E, Maude RJ, Ghani AC, Penny MA, Gerardin J, White LJ, Chitnis N, Aguas R, Hay SI, Smith DL, Stuckey EM, Okiro EA, Smith TA, Okell LC. Model citizen - Authors' reply. LANCET GLOBAL HEALTH 2017; 5:e974. [PMID: 28911762 PMCID: PMC7004815 DOI: 10.1016/s2214-109x(17)30338-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 08/08/2017] [Indexed: 01/25/2023]
Affiliation(s)
- Oliver J Brady
- Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, and Malaria Modelling Consortium, London School of Hygiene & Tropical Medicine, London, UK
| | - Hannah C Slater
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College, London W2 1PG, UK
| | - Peter Pemberton-Ross
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | | | - Richard J Maude
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK; Harvard TH Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Azra C Ghani
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College, London W2 1PG, UK
| | - Melissa A Penny
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | | | - Lisa J White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Nakul Chitnis
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Ricardo Aguas
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Simon I Hay
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK; Malaria Modelling Consortium, University of Washington, Seattle, WA, USA; Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Erin M Stuckey
- Malaria Modelling Consortium, Bill & Melinda Gates Foundation, Seattle, WA, USA
| | - Emelda A Okiro
- Malaria Modelling Consortium, Bill & Melinda Gates Foundation, Seattle, WA, USA; Kemri Wellcome Trust Research Programme, Nairobi, Kenya
| | - Thomas A Smith
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Lucy C Okell
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College, London W2 1PG, UK.
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Bretscher MT, Griffin JT, Ghani AC, Okell LC. Modelling the benefits of long-acting or transmission-blocking drugs for reducing Plasmodium falciparum transmission by case management or by mass treatment. Malar J 2017; 16:341. [PMID: 28814310 PMCID: PMC5559805 DOI: 10.1186/s12936-017-1988-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 08/09/2017] [Indexed: 11/16/2022] Open
Abstract
Background Anti-malarial drugs are an important tool for malaria control and elimination. Alongside their direct benefit in the treatment of disease, drug use has a community-level effect, clearing the reservoir of infection and reducing onward transmission of the parasite. Different compounds potentially have different impacts on transmission—with some providing periods of prolonged chemoprophylaxis whilst others have greater transmission-blocking potential. The aim was to quantify the relative benefit of such properties for transmission reduction to inform target product profiles in the drug development process and choice of first-line anti-malarial treatment in different endemic settings. Methods A mathematical model of Plasmodium falciparum epidemiology was used to estimate the transmission reduction that can be achieved by using drugs of varying chemoprophylactic (protection for 3, 30 or 60 days) or transmission-blocking activity (blocking 79, 92 or 100% of total onward transmission). Simulations were conducted at low, medium or high transmission intensity (slide-prevalence in 2–10 year olds being 1, 10 or 40%, respectively), with drugs administered either via case management or mass drug administration (MDA). Results Transmission reductions depend strongly on deployment strategy, treatment coverage and endemicity level. Transmission-blocking was most effective at low endemicity, whereas chemoprophylaxis was most useful at high endemicity levels. Increasing the duration of protection as much as possible was beneficial. Increasing transmission-blocking activity from the level of ACT to a 100% transmission-blocking drug (close to the effect estimated for ACT combined with primaquine) produced moderate impact but was not as effective as increasing the duration of protection in medium-to-high transmission settings (slide prevalence 10–40%). Combining both good transmission-blocking activity (e.g. as achieved by ACT or ACT + primaquine) and a long duration of protection (30 days or more, such as provided by piperaquine or mefloquine) within a drug regimen can substantially increase impact compared with drug regimens with only one of these properties in medium to high transmission areas (slide-prevalence in 2–10 year olds ~10 to 40%). These results applied whether the anti-malarials were used for case management or for MDA. Discussion These results emphasise the importance of increasing access to treatment for routine case management, and the potential value of choosing first-line anti-malarial treatment policies according to local malaria epidemiology to maximise impact on transmission. There is no indication that the optimal drug choice should differ between delivery via case management or MDA. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1988-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael T Bretscher
- Department of Infectious Disease Epidemiology, MRC Centre for Outbreak Analysis & Modelling, Imperial College, London, UK.,F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Jamie T Griffin
- School of Mathematical Sciences, Queen Mary University of London, London, UK
| | - Azra C Ghani
- Department of Infectious Disease Epidemiology, MRC Centre for Outbreak Analysis & Modelling, Imperial College, London, UK
| | - Lucy C Okell
- Department of Infectious Disease Epidemiology, MRC Centre for Outbreak Analysis & Modelling, Imperial College, London, UK.
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Samuels AM, Awino N, Odongo W, Abong'o B, Gimnig J, Otieno K, Shi YP, Were V, Allen DR, Were F, Sang T, Obor D, Williamson J, Hamel MJ, Patrick Kachur S, Slutsker L, Lindblade KA, Kariuki S, Desai M. Community-based intermittent mass testing and treatment for malaria in an area of high transmission intensity, western Kenya: study design and methodology for a cluster randomized controlled trial. Malar J 2017; 16:240. [PMID: 28592250 PMCID: PMC5463392 DOI: 10.1186/s12936-017-1883-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 05/29/2017] [Indexed: 01/13/2023] Open
Abstract
Most human Plasmodium infections in western Kenya are asymptomatic and are believed to contribute importantly to malaria transmission. Elimination of asymptomatic infections requires active treatment approaches, such as mass testing and treatment (MTaT) or mass drug administration (MDA), as infected persons do not seek care for their infection. Evaluations of community-based approaches that are designed to reduce malaria transmission require careful attention to study design to ensure that important effects can be measured accurately. This manuscript describes the study design and methodology of a cluster-randomized controlled trial to evaluate a MTaT approach for malaria transmission reduction in an area of high malaria transmission. Ten health facilities in western Kenya were purposively selected for inclusion. The communities within 3 km of each health facility were divided into three clusters of approximately equal population size. Two clusters around each health facility were randomly assigned to the control arm, and one to the intervention arm. Three times per year for 2 years, after the long and short rains, and again before the long rains, teams of community health volunteers visited every household within the intervention arm, tested all consenting individuals with malaria rapid diagnostic tests, and treated all positive individuals with an effective anti-malarial. The effect of mass testing and treatment on malaria transmission was measured through population-based longitudinal cohorts, outpatient visits for clinical malaria, periodic population-based cross-sectional surveys, and entomological indices.
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Affiliation(s)
- Aaron M Samuels
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA. .,Centers for Disease Control and Prevention, Kisian Campus, Off Busia Road, P O Box 1578, Kisumu, 40100, Kenya.
| | - Nobert Awino
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Wycliffe Odongo
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Benard Abong'o
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - John Gimnig
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Kephas Otieno
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ya Ping Shi
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Vincent Were
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Denise Roth Allen
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Florence Were
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Tony Sang
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - David Obor
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - John Williamson
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Mary J Hamel
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - S Patrick Kachur
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Laurence Slutsker
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Kim A Lindblade
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Meghna Desai
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
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Walker PGT, Griffin JT, Ferguson NM, Ghani AC. Estimating the most efficient allocation of interventions to achieve reductions in Plasmodium falciparum malaria burden and transmission in Africa: a modelling study. LANCET GLOBAL HEALTH 2016; 4:e474-84. [PMID: 27269393 DOI: 10.1016/s2214-109x(16)30073-0] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 04/04/2016] [Accepted: 04/21/2016] [Indexed: 11/26/2022]
Abstract
BACKGROUND Reducing the burden of malaria is a global priority, but financial constraints mean that available resources must be allocated rationally to maximise their effect. We aimed to develop a model to estimate the most efficient (ie, minimum cost) ordering of interventions to reduce malaria burden and transmission. We also aimed to estimate the efficiency of different spatial scales of implementation. METHODS We combined a dynamic model capturing heterogeneity in malaria transmission across Africa with financial unit cost data for key malaria interventions. We combined estimates of patterns of malaria endemicity, seasonality in rainfall, and mosquito composition to map optimum packages of these interventions across Africa. Using non-linear optimisation methods, we examined how these optimum packages vary when control measures are deployed and assessed at national, subnational first administrative (provincial), or fine-scale (5 km(2) pixel) spatial scales. FINDINGS The most efficient package in a given setting varies depending on whether disease reduction or elimination is the target. Long-lasting insecticide-treated nets are generally the most cost-effective first intervention to achieve either goal, with seasonal malaria chemoprevention or indoor residual spraying added second depending on seasonality and vector species. These interventions are estimated to reduce malaria transmission to less than one case per 1000 people per year in 43·4% (95% CI 40·0-49·0) of the population at risk in Africa. Adding three rounds of mass drug administration per year is estimated to increase this proportion to 90·9% (95% CI 86·9-94·6). Further optimisation can be achieved by targeting policies at the provincial level, achieving an estimated 32·1% (95% CI 29·6-34·5) cost saving relative to adopting country-wide policies. Nevertheless, we predict that only 26 (95% CI 22-29) of 41 countries could reduce transmission to these levels with these approaches. INTERPRETATION These results highlight the cost-benefits of carefully tailoring malaria interventions to the ecological landscape of different areas. However, novel interventions are necessary if malaria eradication is to be achieved. FUNDING Bill & Melinda Gates Foundation, UK Medical Research Council.
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Affiliation(s)
- Patrick G T Walker
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
| | - Jamie T Griffin
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Neil M Ferguson
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Azra C Ghani
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
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Peixoto HM, Brito MAM, Romero GAS, Monteiro WM, de Lacerda MVG, de Oliveira MRF. Cost-effectiveness analysis of rapid diagnostic tests for G6PD deficiency in patients with Plasmodium vivax malaria in the Brazilian Amazon. Malar J 2016; 15:82. [PMID: 26864333 PMCID: PMC4750282 DOI: 10.1186/s12936-016-1140-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 02/02/2016] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The use of primaquine (PQ) for radical treatment of Plasmodium vivax in carriers of G6PD deficiency (G6PDd) constitutes the main factor associated with severe haemolysis in G6PDd. The current study aimed to estimate the incremental cost-effectiveness ratio of using a rapid diagnostic test (RDT) to detect G6PDd in male patients with P. vivax malaria in the Brazilian Amazon, in comparison with the routine indicated by the Programme for Malaria Control, which does not include this evaluation. METHODS A cost-effectiveness analysis of estimated RDT use was carried out for the Brazilian Amazon for the year 2013, considering the perspective of the Brazilian Public Health System. Using decision trees, estimates were compared for two different RDT strategies for G6PDd in male individuals infected with P. vivax before being prescribed PQ, with the routine indicated in Brazil, which does not include prior diagnosis of G6PDd. The first strategy considered the combined use of RDT BinaxNOW(®) G6PD (BX-G6PD) in municipalities with more than 100,000 inhabitants and the routine programme (RP) for the other municipalities. Operational limitations related to the required temperature control and venous blood collection currently restrict the use of RDT BX-G6PD in small municipalities. The second strategy considered the use of the RDT CareStart™ G6PD (CS-G6PD) in 100 % of the municipalities. The analysis was carried out for the outcomes: "adequately diagnosed case" and "hospitalization avoided". RESULTS For the outcome "adequately diagnosed case", comparing the RDT strategies based on RDT with the routine control programme (RP), the CS-G6PD strategy was the most cost-effective, with BX-G6PD extendedly dominating (the ICER of BX-G6PD compared with RP was higher than the ICER of CS-G6PD compared with RP). CS-G6PD dominated the other strategies for the "hospitalization avoided" outcome. CONCLUSION The CS-G6PD strategy is cost-effective for adequately diagnosing cases and avoiding hospitalization. This information can help in decision-making, both in incorporating prior diagnosis in the use of PQ and to promote greater safety among G6PD deficient individuals in the Brazilian Amazon P. vivax endemic areas.
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Affiliation(s)
- Henry M Peixoto
- Center for Tropical Medicine, University of Brasília, Brasília, Federal District, Brazil. .,University Centre of Brasília, Brasília, Federal District, Brazil. .,National Institute for Science and Technology for Health Technology Assessment (IATS/CNPq), Porto Alegre, Rio Grande do Sul, Brazil.
| | - Marcelo A M Brito
- Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil. .,University of the State of Amazonas, Manaus, Amazonas, Brazil.
| | - Gustavo A S Romero
- Center for Tropical Medicine, University of Brasília, Brasília, Federal District, Brazil. .,National Institute for Science and Technology for Health Technology Assessment (IATS/CNPq), Porto Alegre, Rio Grande do Sul, Brazil.
| | - Wuelton M Monteiro
- Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil. .,University of the State of Amazonas, Manaus, Amazonas, Brazil.
| | - Marcus V G de Lacerda
- Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil. .,Instituto Leônidas e Maria Deane, FIOCRUZ, Manaus, Amazonas, Brazil.
| | - Maria R F de Oliveira
- Center for Tropical Medicine, University of Brasília, Brasília, Federal District, Brazil. .,National Institute for Science and Technology for Health Technology Assessment (IATS/CNPq), Porto Alegre, Rio Grande do Sul, Brazil.
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Dierickx S, Gryseels C, Mwesigwa J, O’Neill S, Bannister-Tyrell M, Ronse M, Jaiteh F, Gerrets R, D’Alessandro U, Grietens KP. Factors Associated with Non-Participation and Non-Adherence in Directly Observed Mass Drug Administration for Malaria in The Gambia. PLoS One 2016; 11:e0148627. [PMID: 26866685 PMCID: PMC4750858 DOI: 10.1371/journal.pone.0148627] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/20/2016] [Indexed: 11/27/2022] Open
Abstract
Introduction The potential benefits of Mass Drug Administration (MDA) for malaria elimination are being considered in several malaria endemic countries where a decline in malaria transmission has been reported. For this strategy to work, it is important that a large proportion of the target population participates, requiring an in-depth understanding of factors that may affect participation and adherence to MDA programs. Methodology This social science study was ancillary to a one-round directly observed MDA campaign with dihydroartemisinin-piperaquine, carried out in 12 villages in rural Gambia between June and August 2014. The social science study employed a mixed-methods approach combining qualitative methods (participant observation and in-depth interviewing) and quantitative methods (structured follow-up interviews among non-participating and non-adhering community members). Results Of 3942 people registered in the study villages, 67.9% adhered to the three consecutive daily doses. For the remaining villagers, 12.6% did not attend the screening, 3.5% was not eligible and 16% did not adhere to the treatment schedule. The main barriers for non-participation and adherence were long and short-term mobility of individuals and specific subgroups, perceived adverse drug reactions and rumors, inconveniences related to the logistics of MDA (e.g. waiting times) and the perceived lack of information about MDA. Conclusion While, there was no fundamental resistance from the target communities, adherence was 67.9%. This shows the necessity of understanding local perceptions and barriers to increase its effectiveness. Moreover, certain of the constraining factors were socio-spatially clustered which might prove problematic since focal areas of residual malaria transmission may remain allowing malaria to spread to adjacent areas where transmission had been temporarily interrupted.
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Affiliation(s)
- Susan Dierickx
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
- Amsterdam Institute of Social Science Research, Amsterdam, The Netherlands
- Rhea, Centre of Expertise Gender, Diversity and Intersectionality, Vrije Universiteit Brussel, Brussels, Belgium
- * E-mail:
| | - Charlotte Gryseels
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
- Amsterdam Institute of Social Science Research, Amsterdam, The Netherlands
| | | | - Sarah O’Neill
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | | | - Maya Ronse
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - Fatou Jaiteh
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
- Medical Research Council Unit, Fajara, The Gambia
| | - René Gerrets
- Amsterdam Institute of Social Science Research, Amsterdam, The Netherlands
| | - Umberto D’Alessandro
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
- Medical Research Council Unit, Fajara, The Gambia
- London School of Tropical Medicine and Hygiene, London, Unoted Kingdom
| | - Koen Peeters Grietens
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
- Partners for Applied Social Sciences (PASS) International, Tessenderlo, Belgium
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
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21
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Drake TL, Devine A, Yeung S, Day NPJ, White LJ, Lubell Y. Dynamic Transmission Economic Evaluation of Infectious Disease Interventions in Low- and Middle-Income Countries: A Systematic Literature Review. HEALTH ECONOMICS 2016; 25 Suppl 1:124-39. [PMID: 26778620 PMCID: PMC5066646 DOI: 10.1002/hec.3303] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Economic evaluation using dynamic transmission models is important for capturing the indirect effects of infectious disease interventions. We examine the use of these methods in low- and middle-income countries, where infectious diseases constitute a major burden. This review is comprised of two parts: (1) a summary of dynamic transmission economic evaluations across all disease areas published between 2011 and mid-2014 and (2) an in-depth review of mosquito-borne disease studies focusing on health economic methods and reporting. Studies were identified through a systematic search of the MEDLINE database and supplemented by reference list screening. Fifty-seven studies were eligible for inclusion in the all-disease review. The most common subject disease was HIV/AIDS, followed by malaria. A diverse range of modelling methods, outcome metrics and sensitivity analyses were used, indicating little standardisation. Seventeen studies were included in the mosquito-borne disease review. With notable exceptions, most studies did not employ economic evaluation methods beyond calculating a cost-effectiveness ratio or net benefit. Many did not adhere to health care economic evaluations reporting guidelines, particularly with respect to full model reporting and uncertainty analysis. We present a summary of the state-of-the-art and offer recommendations for improved implementation and reporting of health economic methods in this crossover discipline.
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Affiliation(s)
- Tom L Drake
- University of Oxford, Oxford, UK
- Mahidol University, Bangkok, Thailand
| | - Angela Devine
- University of Oxford, Oxford, UK
- Mahidol University, Bangkok, Thailand
| | - Shunmay Yeung
- London School of Hygiene and Tropical Medicine, London, UK
| | - Nicholas P J Day
- University of Oxford, Oxford, UK
- Mahidol University, Bangkok, Thailand
| | - Lisa J White
- University of Oxford, Oxford, UK
- Mahidol University, Bangkok, Thailand
| | - Yoel Lubell
- University of Oxford, Oxford, UK
- Mahidol University, Bangkok, Thailand
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22
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Mappin B, Cameron E, Dalrymple U, Weiss DJ, Bisanzio D, Bhatt S, Gething PW. Standardizing Plasmodium falciparum infection prevalence measured via microscopy versus rapid diagnostic test. Malar J 2015; 14:460. [PMID: 26577805 PMCID: PMC4650290 DOI: 10.1186/s12936-015-0984-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/03/2015] [Indexed: 11/21/2022] Open
Abstract
Background Large-scale mapping of Plasmodium falciparum infection
prevalence relies on opportunistic assemblies of infection prevalence data arising from thousands of P. falciparum parasite rate (PfPR) surveys conducted worldwide. Variance in these data is driven by both signal, the true underlying pattern of infection prevalence, and a range of factors contributing to ‘noise’, including sampling error, differing age ranges of subjects and differing parasite detection methods. Whilst the former two noise components have been addressed in previous studies, the effect of different diagnostic methods used to determine PfPR in different studies has not. In particular, the majority of PfPR data are based on positivity rates determined by either microscopy or rapid diagnostic test (RDT), yet these approaches are not equivalent; therefore a method is needed for standardizing RDT and microscopy-based prevalence estimates prior to use in mapping. Methods Twenty-five recent Demographic and Health surveys (DHS) datasets from sub-Saharan Africa provide child diagnostic test results derived using both RDT and microscopy for each individual. These prevalence estimates were aggregated across level one administrative zones and a Bayesian probit regression model fit to the microscopy- versus RDT-derived prevalence relationship. An errors-in-variables approach was employed to account for sampling error in both the dependent and independent variables. In addition to the diagnostic outcome, RDT type, fever status and recent anti-malarial treatment were extracted from the datasets in order to analyse their effect on observed malaria prevalence. Results A strong non-linear relationship between the microscopy and RDT-derived prevalence was found. The results of regressions stratified by the additional diagnostic variables (RDT type, fever status and recent anti-malarial treatment) indicate that there is a distinct and consistent difference in the relationship when the data are stratified by febrile status and RDT brand. Conclusions The relationships defined in this research can be applied to RDT-derived PfPR data to effectively convert them to an estimate of the parasite prevalence expected using microscopy (or vice versa), thereby standardizing the dataset and improving the signal-to-noise ratio. Additionally, the results provide insight on the importance of RDT brands, febrile status and recent anti-malarial treatment for explaining inconsistencies between observed prevalence derived from different diagnostics.
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Affiliation(s)
- Bonnie Mappin
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Tinbergen Building, Oxford, OX1 3PS, UK.
| | - Ewan Cameron
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Tinbergen Building, Oxford, OX1 3PS, UK.
| | - Ursula Dalrymple
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Tinbergen Building, Oxford, OX1 3PS, UK.
| | - Daniel J Weiss
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Tinbergen Building, Oxford, OX1 3PS, UK.
| | - Donal Bisanzio
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Tinbergen Building, Oxford, OX1 3PS, UK.
| | - Samir Bhatt
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Tinbergen Building, Oxford, OX1 3PS, UK.
| | - Peter W Gething
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Tinbergen Building, Oxford, OX1 3PS, UK.
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23
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Parham PE, Hughes DA. Climate influences on the cost-effectiveness of vector-based interventions against malaria in elimination scenarios. Philos Trans R Soc Lond B Biol Sci 2015; 370:rstb.2013.0557. [PMID: 25688017 DOI: 10.1098/rstb.2013.0557] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Despite the dependence of mosquito population dynamics on environmental conditions, the associated impact of climate and climate change on present and future malaria remains an area of ongoing debate and uncertainty. Here, we develop a novel integration of mosquito, transmission and economic modelling to assess whether the cost-effectiveness of indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) against Plasmodium falciparum transmission by Anopheles gambiae s.s. mosquitoes depends on climatic conditions in low endemicity scenarios. We find that although temperature and rainfall affect the cost-effectiveness of IRS and/or LLIN scale-up, whether this is sufficient to influence policy depends on local endemicity, existing interventions, host immune response to infection and the emergence rate of insecticide resistance. For the scenarios considered, IRS is found to be more cost-effective than LLINs for the same level of scale-up, and both are more cost-effective at lower mean precipitation and higher variability in precipitation and temperature. We also find that the dependence of peak transmission on mean temperature translates into optimal temperatures for vector-based intervention cost-effectiveness. Further cost-effectiveness analysis that accounts for country-specific epidemiological and environmental heterogeneities is required to assess optimal intervention scale-up for elimination and better understand future transmission trends under climate change.
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Affiliation(s)
- Paul E Parham
- Department of Public Health and Policy, University of Liverpool, London, EC2A 1AG, UK
| | - Dyfrig A Hughes
- Centre for Health Economics and Medicines Evaluation, Bangor University, Bangor, LL57 2PZ, UK
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24
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Robinson LJ, Wampfler R, Betuela I, Karl S, White MT, Li Wai Suen CSN, Hofmann NE, Kinboro B, Waltmann A, Brewster J, Lorry L, Tarongka N, Samol L, Silkey M, Bassat Q, Siba PM, Schofield L, Felger I, Mueller I. Strategies for understanding and reducing the Plasmodium vivax and Plasmodium ovale hypnozoite reservoir in Papua New Guinean children: a randomised placebo-controlled trial and mathematical model. PLoS Med 2015; 12:e1001891. [PMID: 26505753 PMCID: PMC4624431 DOI: 10.1371/journal.pmed.1001891] [Citation(s) in RCA: 190] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 09/17/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The undetectable hypnozoite reservoir for relapsing Plasmodium vivax and P. ovale malarias presents a major challenge for malaria control and elimination in endemic countries. This study aims to directly determine the contribution of relapses to the burden of P. vivax and P. ovale infection, illness, and transmission in Papua New Guinean children. METHODS AND FINDINGS From 17 August 2009 to 20 May 2010, 524 children aged 5-10 y from East Sepik Province in Papua New Guinea (PNG) participated in a randomised double-blind placebo-controlled trial of blood- plus liver-stage drugs (chloroquine [CQ], 3 d; artemether-lumefantrine [AL], 3 d; and primaquine [PQ], 20 d, 10 mg/kg total dose) (261 children) or blood-stage drugs only (CQ, 3 d; AL, 3 d; and placebo [PL], 20 d) (263 children). Participants, study staff, and investigators were blinded to the treatment allocation. Twenty children were excluded during the treatment phase (PQ arm: 14, PL arm: 6), and 504 were followed actively for 9 mo. During the follow-up time, 18 children (PQ arm: 7, PL arm: 11) were lost to follow-up. Main primary and secondary outcome measures were time to first P. vivax infection (by qPCR), time to first clinical episode, force of infection, gametocyte positivity, and time to first P. ovale infection (by PCR). A basic stochastic transmission model was developed to estimate the potential effect of mass drug administration (MDA) for the prevention of recurrent P. vivax infections. Targeting hypnozoites through PQ treatment reduced the risk of having at least one qPCR-detectable P. vivax or P. ovale infection during 8 mo of follow-up (P. vivax: PQ arm 0.63/y versus PL arm 2.62/y, HR = 0.18 [95% CI 0.14, 0.25], p < 0.001; P. ovale: 0.06 versus 0.14, HR = 0.31 [95% CI 0.13, 0.77], p = 0.011) and the risk of having at least one clinical P. vivax episode (HR = 0.25 [95% CI 0.11, 0.61], p = 0.002). PQ also reduced the molecular force of P. vivax blood-stage infection in the first 3 mo of follow-up (PQ arm 1.90/y versus PL arm 7.75/y, incidence rate ratio [IRR] = 0.21 [95% CI 0.15, 0.28], p < 0.001). Children who received PQ were less likely to carry P. vivax gametocytes (IRR = 0.27 [95% CI 0.19, 0.38], p < 0.001). PQ had a comparable effect irrespective of the presence of P. vivax blood-stage infection at the time of treatment (p = 0.14). Modelling revealed that mass screening and treatment with highly sensitive quantitative real-time PCR, or MDA with blood-stage treatment alone, would have only a transient effect on P. vivax transmission levels, while MDA that includes liver-stage treatment is predicted to be a highly effective strategy for P. vivax elimination. The inclusion of a directly observed 20-d treatment regime maximises the efficiency of hypnozoite clearance but limits the generalisability of results to real-world MDA programmes. CONCLUSIONS These results suggest that relapses cause approximately four of every five P. vivax infections and at least three of every five P. ovale infections in PNG children and are important in sustaining transmission. MDA campaigns combining blood- and liver-stage treatment are predicted to be a highly efficacious intervention for reducing P. vivax and P. ovale transmission. TRIAL REGISTRATION ClinicalTrials.gov NCT02143934.
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Affiliation(s)
- Leanne J. Robinson
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang and Maprik, Papua New Guinea
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Rahel Wampfler
- Molecular Diagnostics Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Inoni Betuela
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang and Maprik, Papua New Guinea
| | - Stephan Karl
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Michael T. White
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, United Kingdom
| | - Connie S. N. Li Wai Suen
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Natalie E. Hofmann
- Molecular Diagnostics Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Benson Kinboro
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang and Maprik, Papua New Guinea
| | - Andreea Waltmann
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Jessica Brewster
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Lina Lorry
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang and Maprik, Papua New Guinea
| | - Nandao Tarongka
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang and Maprik, Papua New Guinea
| | - Lornah Samol
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang and Maprik, Papua New Guinea
| | - Mariabeth Silkey
- Molecular Diagnostics Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Quique Bassat
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Peter M. Siba
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang and Maprik, Papua New Guinea
- School of Veterinary and Biomedical Sciences, James Cook University, Townsville, Queensland, Australia
| | - Louis Schofield
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Ingrid Felger
- Molecular Diagnostics Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Ivo Mueller
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
- ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clínic–University of Barcelona, Barcelona, Spain
- * E-mail:
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25
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Linn AM, Ndiaye Y, Hennessee I, Gaye S, Linn P, Nordstrom K, McLaughlin M. Reduction in symptomatic malaria prevalence through proactive community treatment in rural Senegal. Trop Med Int Health 2015; 20:1438-1446. [PMID: 26171642 DOI: 10.1111/tmi.12564] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES We piloted a community-based proactive malaria case detection model in rural Senegal to evaluate whether this model can increase testing and treatment and reduce prevalence of symptomatic malaria in target communities. METHODS Home care providers conducted weekly sweeps of every household in their village throughout the transmission season to identify patients with symptoms of malaria, perform rapid diagnostic tests (RDT) on symptomatic patients and provide treatment for positive cases. The model was implemented in 15 villages from July to November 2013, the high transmission season. Fifteen comparison villages were chosen from those implementing Senegal's original, passive model of community case management of malaria. Three sweeps were conducted in the comparison villages to compare prevalence of symptomatic malaria using difference in differences analysis. RESULTS At baseline, prevalence of symptomatic malaria confirmed by RDT for all symptomatic individuals found during sweeps was similar in both sets of villages (P = 0.79). At end line, prevalence was 16 times higher in the comparison villages than in the intervention villages (P = 0.003). Adjusting for potential confounders, the intervention was associated with a 30-fold reduction in odds of symptomatic malaria in the intervention villages (AOR = 0.033; 95% CI: 0.017, 0.065). Treatment seeking also increased in the intervention villages, with 57% of consultations by home care providers conducted between sweeps through routine community case management. CONCLUSIONS This pilot study suggests that community-based proactive case detection reduces symptomatic malaria prevalence, likely through more timely case management and improved care seeking behaviour. A randomised controlled trial is needed to further evaluate the impact of this model.
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Affiliation(s)
- Annē M Linn
- Peace Corps, Department of Saraya, Senegal.,Rutgers School of Nursing, Newark, NJ, USA
| | | | - Ian Hennessee
- Peace Corps, Department of Saraya, Senegal.,Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | | | - Patrick Linn
- Peace Corps, Department of Saraya, Senegal.,Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, NJ, USA
| | - Karin Nordstrom
- Peace Corps, Department of Saraya, Senegal.,Moritz College of Law, The Ohio State University, Winchester, OH, USA
| | - Matt McLaughlin
- Stomping Out Malaria in Africa Initiative, US Peace Corps, Washington, DC, USA
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Pemberton-Ross P, Smith TA, Hodel EM, Kay K, Penny MA. Age-shifting in malaria incidence as a result of induced immunological deficit: a simulation study. Malar J 2015; 14:287. [PMID: 26206255 PMCID: PMC4513612 DOI: 10.1186/s12936-015-0805-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 07/10/2015] [Indexed: 11/10/2022] Open
Abstract
Effective population-level interventions against Plasmodium falciparum malaria lead to age-shifts, delayed morbidity or rebounds in morbidity and mortality whenever they are deployed in ways that do not permanently interrupt transmission. When long-term intervention programmes target specific age-groups of human hosts, the age-specific morbidity rates ultimately adjust to new steady-states, but it is very difficult to study these rates and the temporal dynamics leading up to them empirically because the changes occur over very long time periods. This study investigates the age and magnitude of age- and time- shifting of incidence induced by either pre-erythrocytic vaccination (PEV) programmes or seasonal malaria chemo-prevention (SMC), using an ensemble of individual-based stochastic simulation models of P. falciparum dynamics. The models made various assumptions about immunity decay, transmission heterogeneity and were parameterized with data on both age-specific infection and disease incidence at different levels of exposure, on the durations of different stages of the parasite life-cycle and on human demography. Effects of transmission intensity, and of levels of access to malaria treatment were considered. While both PEV and SMC programmes are predicted to have overall strongly positive health effects, a shift of morbidity into older children is predicted to be induced by either programme if transmission levels remain static and not reduced by other interventions. Predicted shifting of burden continue into the second decade of the programme. Even if long-term surveillance is maintained it will be difficult to avoid mis-attribution of such long-term changes in age-specific morbidity patterns to other factors. Conversely, short-lived transient changes in incidence measured soon after introduction of a new intervention may give over-positive views of future impacts. Complementary intervention strategies could be designed to specifically protect those age-groups at risk from burden shift.
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Affiliation(s)
- Peter Pemberton-Ross
- Swiss Tropical and Public Health Institute, 4002, Basel, Switzerland.
- Universität Basel, 4003, Basel, Switzerland.
| | - Thomas A Smith
- Swiss Tropical and Public Health Institute, 4002, Basel, Switzerland.
- Universität Basel, 4003, Basel, Switzerland.
| | - Eva Maria Hodel
- Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.
| | - Katherine Kay
- Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.
| | - Melissa A Penny
- Swiss Tropical and Public Health Institute, 4002, Basel, Switzerland.
- Universität Basel, 4003, Basel, Switzerland.
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Silal SP, Little F, Barnes KI, White LJ. Predicting the impact of border control on malaria transmission: a simulated focal screen and treat campaign. Malar J 2015; 14:268. [PMID: 26164675 PMCID: PMC4499227 DOI: 10.1186/s12936-015-0776-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 06/28/2015] [Indexed: 12/31/2022] Open
Abstract
Background South Africa is one of many countries committed to malaria elimination with a target of 2018 and all malaria-endemic provinces, including Mpumalanga, are increasing efforts towards this ambitious goal. The reduction of imported infections is a vital element of an elimination strategy, particularly if a country is already experiencing high levels of imported infections. Border control of malaria is one tool that may be considered. Methods A metapopulation, non-linear stochastic ordinary differential equation model is used to simulate malaria transmission in Mpumalanga and Maputo province, Mozambique (the source of the majority of imported infections) to predict the impact of a focal screen and treat campaign at the Mpumalanga–Maputo border. This campaign is simulated by nesting an individual-based model for the focal screen and treat campaign within the metapopulation transmission model. Results The model predicts that such a campaign, simulated for different levels of resources, coverage and take-up rates with a variety of screening tools, will not eliminate malaria on its own, but will reduce transmission substantially. Making the campaign mandatory decreases transmission further though sub-patent infections are likely to remain undetected if the diagnostic tool is not adequately sensitive. Replacing screening and treating with mass drug administration results in substantially larger decreases as all (including sub-patent) infections are treated before movement into Mpumalanga. Conclusions The reduction of imported cases will be vital to any future malaria control or elimination strategy. This simulation predicts that FSAT at the Mpumalanga–Maputo border will be unable to eliminate local malaria on its own, but may still play a key role in detecting and treating imported infections before they enter the country. Thus FSAT may form part of an integrated elimination strategy where a variety of interventions are employed together to achieve malaria elimination. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0776-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sheetal P Silal
- Department of Statistical Sciences, University of Cape Town, Rondebosch, Cape Town, 7700, South Africa.
| | - Francesca Little
- Department of Statistical Sciences, University of Cape Town, Rondebosch, Cape Town, 7700, South Africa.
| | - Karen I Barnes
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
| | - Lisa J White
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand. .,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK.
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Silumbe K, Yukich JO, Hamainza B, Bennett A, Earle D, Kamuliwo M, Steketee RW, Eisele TP, Miller JM. Costs and cost-effectiveness of a large-scale mass testing and treatment intervention for malaria in Southern Province, Zambia. Malar J 2015; 14:211. [PMID: 25985992 PMCID: PMC4490652 DOI: 10.1186/s12936-015-0722-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 05/05/2015] [Indexed: 11/17/2022] Open
Abstract
Background A cluster, randomized, control trial of three dry-season rounds of a mass testing and treatment intervention (MTAT) using rapid diagnostic tests (RDTs) and artemether-lumefantrine (AL) was conducted in four districts in Southern Province, Zambia. Methods Data were collected on the costs and logistics of the intervention and paired with effectiveness estimated from a community randomized control trial for the purpose of conducting a provider perspective cost-effectiveness analysis of MTAT vs no MTAT (Standard of Care). Results Dry-season MTAT in this setting did not reduce malaria transmission sufficiently to permit transition to a case-investigation strategy to then pursue malaria elimination, however, the intervention did substantially reduce malaria illness and was a highly cost-effective intervention for malaria burden reduction in this moderate transmission area. The cost per RDT administered was estimated to be USD4.39 (range: USD1.62-13.96) while the cost per AL treatment administered was estimated to be USD34.74 (range: USD3.87-3,835). The net cost per disability adjusted life year averted (incremental cost-effectiveness ratio) was estimated to be USD804. Conclusions The intervention appears to be highly cost-effective relative to World Health Organization thresholds for malaria burden reduction in Zambia as compared to no MTAT. However, it was estimated that population-wide mass drug administration is likely to be more cost-effective for burden reduction and for transmission reduction compared to MTAT.
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Affiliation(s)
- Kafula Silumbe
- Malaria Control and Evaluation Partnership in Africa (PATH-MACEPA), Lusaka, Zambia.
| | - Joshua O Yukich
- Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA.
| | | | - Adam Bennett
- Malaria Elimination Initiative, University of California San Francisco, San Francisco, USA.
| | - Duncan Earle
- Malaria Control and Evaluation Partnership in Africa (PATH-MACEPA), Lusaka, Zambia.
| | | | - Richard W Steketee
- Malaria Control and Evaluation Partnership in Africa (PATH-MACEPA), Lusaka, Zambia.
| | - Thomas P Eisele
- Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA.
| | - John M Miller
- Malaria Control and Evaluation Partnership in Africa (PATH-MACEPA), Lusaka, Zambia.
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The relationship between Plasmodium infection, anaemia and nutritional status in asymptomatic children aged under five years living in stable transmission zones in Kinshasa, Democratic Republic of Congo. Malar J 2015; 14:83. [PMID: 25880427 PMCID: PMC4336722 DOI: 10.1186/s12936-015-0595-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/30/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria is preventable and treatable when recommended interventions are properly implemented. Thus, diagnosis and treatment focus on symptomatic individuals while asymptomatic Plasmodium infection (PI) plays a role in the sustainability of the transmission and may also have an impact on the morbidity of the disease in terms of anaemia, nutritional status and even cognitive development of children. The objective of this study was to assess PI prevalence and its relationship with known morbidity factors in a vulnerable but asymptomatic stratum of the population. METHODS A simple random sample, household survey in asymptomatic children under the age of five was conducted from April to September 2012 in two health areas of the health zone of Mont Ngafula 1, Kinshasa, Democratic Republic of Congo. RESULTS The PI prevalence were 30.9% (95% CI: 26.5-35.9) and 14.3% (95% CI: 10.5-18.1) in Cité Pumbu and Kindele health areas, respectively, (OR: 2.7; p <0.001). All were Plasmodium falciparum infected and 4% were co-infected with Plasmodium malariae. In Cité Pumbu and Kindele, the prevalence of anaemia (haemoglobin <11 g/dL) was 61.6% (95% CI: 56.6-66.5) and 39.3% (95% CI: 34.0-44.6), respectively, (OR: 2.5; p <0.001). The health area of Cité Pumbu had 32% (95% CI: 27.5-37.0) of chronic malnutrition (HAZ score ≤ -2SD) compared to 5.1% (95% CI: 2.8-7.6) in Kindele. PI was predictor factor for anaemia (aOR: 3.5, p =0.01) and within infected children, there was an inverse relationship between parasite density and haemoglobin level (β = -5*10(-5), p <0.001). Age older than 12 months (aOR: 3.8, p = 0.01), presence of anaemia (aOR: 3.4, p =0.001), chronic malnutrition (aOR: 1.8, p = 0.01), having a single parent/guardian (aOR: 1.6, p =0.04), and the non-use of insecticide-treated nets (aOR: 1.7, p = 0.04) were all predictors for PI in the overall population. CONCLUSION PI in asymptomatic children was correlated with anaemia and chronic malnutrition and was thus a harmful condition in the study population. Malaria control initiatives should not only focus on treatment of symptomatic infections but also take into consideration asymptomatic but infected children.
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Griffin JT. The interaction between seasonality and pulsed interventions against malaria in their effects on the reproduction number. PLoS Comput Biol 2015; 11:e1004057. [PMID: 25590612 PMCID: PMC4295870 DOI: 10.1371/journal.pcbi.1004057] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 11/21/2014] [Indexed: 11/18/2022] Open
Abstract
The basic reproduction number (R0) is an important quantity summarising the dynamics of an infectious disease, as it quantifies how much effort is needed to control transmission. The relative change in R0 due to an intervention is referred to as the effect size. However malaria and other diseases are often highly seasonal and some interventions have time-varying effects, meaning that simple reproduction number formulae cannot be used. Methods have recently been developed for calculating R0 for diseases with seasonally varying transmission. I extend those methods to calculate the effect size of repeated rounds of mass drug administration, indoor residual spraying and other interventions against Plasmodium falciparum malaria in seasonal settings in Africa. I show that if an intervention reduces transmission from one host to another by a constant factor, then its effect size is the same in a seasonal as in a non-seasonal setting. The optimal time of year for drug administration is in the low season, whereas the best time for indoor residual spraying or a vaccine which reduces infection rates is just before the high season. In general, the impact of time-varying interventions increases with increasing seasonality, if carried out at the optimal time of year. The effect of combinations of interventions that act at different stages of the transmission cycle is roughly the product of the separate effects. However for individual time-varying interventions, it is necessary to use methods such as those developed here rather than inserting the average efficacy into a simple formula.
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Affiliation(s)
- Jamie T. Griffin
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, United Kingdom
- * E-mail:
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Tietje K, Hawkins K, Clerk C, Ebels K, McGray S, Crudder C, Okell L, LaBarre P. The essential role of infection-detection technologies for malaria elimination and eradication. Trends Parasitol 2014; 30:259-66. [DOI: 10.1016/j.pt.2014.03.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/11/2014] [Accepted: 03/12/2014] [Indexed: 11/26/2022]
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Hamainza B, Moonga H, Sikaala CH, Kamuliwo M, Bennett A, Eisele TP, Miller J, Seyoum A, Killeen GF. Monitoring, characterization and control of chronic, symptomatic malaria infections in rural Zambia through monthly household visits by paid community health workers. Malar J 2014; 13:128. [PMID: 24678631 PMCID: PMC4113135 DOI: 10.1186/1475-2875-13-128] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 03/23/2014] [Indexed: 11/29/2022] Open
Abstract
Background Active, population-wide mass screening and treatment (MSAT) for chronic Plasmodium falciparum carriage to eliminate infectious reservoirs of malaria transmission have proven difficult to apply on large national scales through trained clinicians from central health authorities. Methodology Fourteen population clusters of approximately 1,000 residents centred around health facilities (HF) in two rural Zambian districts were each provided with three modestly remunerated community health workers (CHWs) conducting active monthly household visits to screen and treat all consenting residents for malaria infection with rapid diagnostic tests (RDT). Both CHWs and HFs also conducted passive case detection among residents who self-reported for screening and treatment. Results Diagnostic positivity was higher among symptomatic patients self-reporting to CHWs (42.5%) and HFs (24%) than actively screened residents (20.3%), but spatial and temporal variations of diagnostic positivity were highly consistent across all three systems. However, most malaria infections (55.6%) were identified through active home visits by CHWs rather than self-reporting to CHWs or HFs. Most (62%) malaria infections detected actively by CHWs reported one or more symptoms of illness. Most reports of fever and vomiting, plus more than a quarter of history of fever, headache and diarrhoea, were attributable to malaria infection. The minority of residents who participated >12 times had lower rates of malaria infection and associated symptoms in later contacts but most residents were tested <4 times and high malaria diagnostic positivity (32%) in active surveys, as well as incidence (1.7 detected infections per person per year) persisted in the population. Per capita cost for active service delivery by CHWs was US$5.14 but this would rise to US$10.68 with full community compliance with monthly testing at current levels of transmission, and US$6.25 if pre-elimination transmission levels and negligible treatment costs were achieved. Conclusion Monthly active home visits by CHWs equipped with RDTs were insufficient to eliminate the human infection reservoir in this typical African setting, despite reasonably high LLIN/IRS coverage. However, dramatic impact upon infection and morbidity burden might be attainable and cost-effective if community participation in regular testing could be improved and the substantial, but not necessarily prohibitive, costs are affordable to national programmes.
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Affiliation(s)
- Busiku Hamainza
- Ministry of Health, National Malaria Control Centre, Chainama Hospital College Grounds, off Great East road, P,O, Box 32509, Lusaka, Zambia.
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Supargiyono S, Bretscher MT, Wijayanti MA, Sutanto I, Nugraheni D, Rozqie R, Kosasih AA, Sulistyawati S, Hawley WA, Lobo NF, Cook J, Drakeley CJ. Seasonal changes in the antibody responses against Plasmodium falciparum merozoite surface antigens in areas of differing malaria endemicity in Indonesia. Malar J 2013; 12:444. [PMID: 24321092 PMCID: PMC3866602 DOI: 10.1186/1475-2875-12-444] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 12/04/2013] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The transmission of malaria in Indonesia is highly heterogeneous spatially and seasonally. Anti-malaria antibody responses can help characterize this variation. In the present study antibody responses to Plasmodium falciparum MSP-1 and AMA-1 were measured to assess the transmission intensity in a hypo-endemic area of Purworejo and a meso-endemic area of Lampung during low and high transmission seasons. METHODS Filter-paper blood spot samples collected from Purworejo and Lampung by cross-sectional survey during high and low transmission season were stored at -20°C. Indirect ELISA assays were carried out using PfMSP1-19 and PfAMA1 antigens. A positivity threshold was determined by samples from local unexposed individuals, and the differences in seroprevalence, antibody level and correlation between antibody level and age in each site were statistically analysed. RESULTS Prevalence of antibodies to either PfMSP1-19 or PfAMA1 was higher in Lampung than in Purworejo in both the low (51.3 vs 25.0%) and high transmission season (53.9 vs 37.5%). The magnitude of antibody responses was associated with increasing age in both sites and was higher in Lampung. Age-adjusted seroconversion rates showed an approximately ten-fold difference between Lampung and Purowejo. Two different seroconversion rates were estimated for Lampung suggesting behaviour-related differences in exposure. In both settings antibody responses to PfMSP1-19 were significantly lower in the low season compared to the high season. CONCLUSION Seasonal changes may be detectable by changes in antibody responses. This is particularly apparent in lower transmission settings and with less immunogenic antigens (in this case PfMSP1-19). Examination of antibody levels rather than seroprevalence is likely to be a more sensitive indicator of changes in transmission. These data suggest that sero-epidemiological analysis may have a role in assessing short-term changes in exposure especially in low or seasonal transmission settings.
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Affiliation(s)
- Supargiyono Supargiyono
- Center for Tropical Medicine, Faculty of Medicine, Gadjah Mada University, Jln Teknika Utara, Barek, Yogyakarta 55281, Indonesia
| | - Michael T Bretscher
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, St Mary’s Campus, Norfolk Place, London W2 1PG, UK
| | - Mahardika A Wijayanti
- Center for Tropical Medicine, Faculty of Medicine, Gadjah Mada University, Jln Teknika Utara, Barek, Yogyakarta 55281, Indonesia
| | - Inge Sutanto
- Department of Parasitology Faculty of Medicine, University of Indonesia, Jln Salemba Raya, Jakarta, Indonesia
| | - Dian Nugraheni
- Center for Tropical Medicine, Faculty of Medicine, Gadjah Mada University, Jln Teknika Utara, Barek, Yogyakarta 55281, Indonesia
| | - Royhan Rozqie
- Center for Tropical Medicine, Faculty of Medicine, Gadjah Mada University, Jln Teknika Utara, Barek, Yogyakarta 55281, Indonesia
| | - Ayleen A Kosasih
- Department of Parasitology Faculty of Medicine, University of Indonesia, Jln Salemba Raya, Jakarta, Indonesia
| | - Sulistyawati Sulistyawati
- Center for Tropical Medicine, Faculty of Medicine, Gadjah Mada University, Jln Teknika Utara, Barek, Yogyakarta 55281, Indonesia
- Department of Public Health Science, Faulty of Public Health, Ahmad Dahlan University, Jln Prof Dr Soepomo, Warungboto, Umbulharjo, Yogyakarta, Indonesia
| | | | - Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Jackie Cook
- Malaria Research Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Chris J Drakeley
- Department of Immunology & Infection, London School of Hygiene and Tropical Medicine, London W1CE 7HT, UK
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Tiono AB, Guelbeogo MW, Sagnon NF, Nébié I, Sirima SB, Mukhopadhyay A, Hamed K. Dynamics of malaria transmission and susceptibility to clinical malaria episodes following treatment of Plasmodium falciparum asymptomatic carriers: results of a cluster-randomized study of community-wide screening and treatment, and a parallel entomology study. BMC Infect Dis 2013; 13:535. [PMID: 24215306 PMCID: PMC4225764 DOI: 10.1186/1471-2334-13-535] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 11/11/2013] [Indexed: 11/10/2022] Open
Abstract
Background In malaria-endemic countries, large proportions of individuals infected with Plasmodium falciparum are asymptomatic and constitute a reservoir of parasites for infection of newly hatched mosquitoes. Methods Two studies were run in parallel in Burkina Faso to evaluate the impact of systematic identification and treatment of asymptomatic carriers of P. falciparum, detected by rapid diagnostic test, on disease transmission and susceptibility to clinical malaria episodes. A clinical study assessed the incidence of symptomatic malaria episodes with a parasite density >5,000/μL after three screening and treatment campaigns ~1 month apart before the rainy season; and an entomological study determined the effect of these campaigns on malaria transmission as measured by entomological inoculation rate. Results The intervention arm had lower prevalence of asymptomatic carriers of asexual parasites and lower prevalence of gametocyte carriers during campaigns 2 and 3 as compared to the control arm. During the entire follow-up period, out of 13,767 at-risk subjects, 2,516 subjects (intervention arm 1,332; control arm 1,184) had symptomatic malaria. Kaplan-Meier analysis of the incidence of first symptomatic malaria episode with a parasite density >5,000/μL showed that, in the total population, the two treatment arms were similar until Week 11–12 after campaign 3, corresponding with the beginning of the malaria transmission season, after which the probability of being free of symptomatic malaria was lower in the intervention arm (logrank p < 0.0001). Similar trends were observed in infants and children <5 years and in individuals ≥5 years of age. In infants and children <5 years old who experienced symptomatic malaria episodes, the geometric mean P. falciparum density was lower in the intervention arm than the control arm. This trend was not seen in those individuals aged ≥5 years. Over the year, monthly variation in mosquito density and entomological inoculation rate was comparable in both arms, with September peaks in both indices. Conclusion Community screening and targeted treatment of asymptomatic carriers of P. falciparum had no effect on the dynamics of malaria transmission, but seemed to be associated with an increase in the treated community’s susceptibility to symptomatic malaria episodes after the screening campaigns had finished. These results highlight the importance of further exploratory studies to better understand the dynamics of disease transmission in the context of malaria elimination.
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Affiliation(s)
- Alfred B Tiono
- Novartis Pharmaceuticals Corporation, One Health Plaza, East Hanover, NJ 07936-1080, USA.
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Killeen GF. A second chance to tackle African malaria vector mosquitoes that avoid houses and don't take drugs. Am J Trop Med Hyg 2013; 88:809-816. [PMID: 23589532 PMCID: PMC3752742 DOI: 10.4269/ajtmh.13-0065] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Gerry F. Killeen
- *Address correspondence to Gerry F. Killeen, Ifakara Health Institute, Environmental Health and Ecological Sciences Thematic Group, PO Box 53, Ifakara, Kilombero District, Morogoro Region, United Republic of Tanzania. E-mail:
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