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Keïta M, Sissoko I, Sogoba N, Konaté M, Diawara SI, Kané F, Thiam S, Touré M, Konaté D, Diakité M, Beier JC, Doumbia S. Resurgence of Malaria Transmission and Incidence after Withdrawal of Indoor Residual Spraying in the District of Koulikoro, Mali. Am J Trop Med Hyg 2023; 109:616-620. [PMID: 37549902 PMCID: PMC10484277 DOI: 10.4269/ajtmh.22-0808] [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: 12/30/2022] [Accepted: 05/25/2023] [Indexed: 08/09/2023] Open
Abstract
In Mali, malaria vector control relies mostly on long-lasting insecticidal nets and indoor residual spraying (IRS). From 2008 to 2016, an IRS program was implemented in the district of Koulikoro. After a significant reduction in malaria indicators, IRS was stopped in 2016. This study evaluated the effect of IRS withdrawal on entomological parameters of malaria transmission and incidence in children aged 6 months to 10 years in the district of Koulikoro. Entomological parameters of malaria transmission during the last year of IRS implementation in 2016 were compared with those obtained 2 years after IRS withdrawal in 2018 in two villages of Koulikoro. Mosquito vectors were collected by mouth aspiration and pyrethrum spray catches in the villages to monitor these transmission parameters. A sharp increase (10.8 times higher) in vector abundance after IRS withdrawal was observed. The infection rate of Anopheles gambiae sensu lato to Plasmodium falciparum increased from zero during IRS implementation to 14.8% after IRS withdrawal. The average entomological inoculation rate, which was undetectable before, was 1.22 infected bites per person per month 2 years after IRS was withdrawn, and the cumulative malaria incidence rate observed after IRS was 4.12 times (15.2% versus 3.7%) higher than that observed in 2016 in the villages before IRS withdrawal. This study showed a resurgence of malaria transmission and incidence in the Koulikoro health district after IRS was withdrawn. Thus, to manage the potential consequences of malaria transmission resurgence, alternative approaches are needed when stopping successful malaria control interventions.
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Affiliation(s)
- Moussa Keïta
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ibrahim Sissoko
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Nafomon Sogoba
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Moussa Konaté
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sory Ibrahim Diawara
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Fousseyni Kané
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Salif Thiam
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamoudou Touré
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Drissa Konaté
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamadou Diakité
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - John C. Beier
- Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, Florida
| | - Seydou Doumbia
- West African International Center for Excellence in Malaria Research/Malaria Research and Training Center/International Center for Excellence in Research/University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
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2
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Doumbia S, Toure M, Sogoba N, Alifrangis M, Diakite M, Diarra A, Keita M, Konaté D, Diawara SI, Thiam SM, Keita S, Tounkara M, Cissé I, Sanogo V, Magassa MH, Barry AE, Winch PJ, Marker HC, Shaffer JG, Traoré SF, Müller GC, Cui L, Beier JC, Mihigo J. The West Africa ICEMR Partnerships for Guiding Policy to Improve the Malaria Prevention and Control. Am J Trop Med Hyg 2022; 107:84-89. [PMID: 36228908 PMCID: PMC9662222 DOI: 10.4269/ajtmh.21-1330] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 07/06/2022] [Indexed: 12/01/2022] Open
Abstract
The Mali National Malaria Control Program (NMCP) recently established a phased set of goals for eliminating malaria in Mali by 2030. Over the past decade, the scale-up of NMCP-led malaria control interventions has led to considerable progress, as evidenced by multiple malariometric indicators. The West Africa International Center of Excellence in Malaria Research (WA-ICEMR) is a multidisciplinary research program that works closely with the NMCP and its partners to address critical research needs for malaria control. This coordinated effort includes assessing the effectiveness of control interventions based on key malaria research topics, including immune status, parasite genetic diversity, insecticide and drug resistance, diagnostic accuracy, malaria vector populations and biting behaviors, and vectorial capacity. Several signature accomplishments of the WA-ICEMR include identifying changing malaria age demographic profiles, testing innovative approaches to improve control strategies, and providing regular reporting on drug and insecticide resistance status. The NMCP and WA-ICEMR partnership between the WA-ICEMR and the NMCP offers a comprehensive research platform that informs the design and implementation of malaria prevention and control research programs. These efforts build local expertise and capacity for the next generation of malaria researchers and guide local policy, which is crucial in sustaining efforts toward eliminating malaria in West Africa.
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Affiliation(s)
- Seydou Doumbia
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamoudou Toure
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Nafomon Sogoba
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Michael Alifrangis
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Mahamadou Diakite
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ayouba Diarra
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Moussa Keita
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Drissa Konaté
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sory I. Diawara
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sidibé M’Baye Thiam
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Soumba Keita
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Moctar Tounkara
- Department of Public Health, Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Idrissa Cissé
- National Malaria Control Program, Ministry of Health, Bamako, Mali
| | - Vincent Sanogo
- National Malaria Control Program, Ministry of Health, Bamako, Mali
| | | | | | - Peter J. Winch
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Hannah C. Marker
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jeffrey G. Shaffer
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana
| | - Sékou F. Traoré
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Günter C. Müller
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Liwang Cui
- Division of Infectious Diseases and Internal Medicine, Department of Internal Medicine, University of South Florida, Tampa, Florida
| | - John C. Beier
- Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, Florida
| | - Jules Mihigo
- U.S. President’s Malaria Initiative, United States Agency for International Development Office, Bamako, Mali
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Doumbia S, Sogoba N, Diakite M, Toure M, Keita M, Konaté D, Diawara SI, Diarra A, Sanogo D, Kane F, Diakite SAS, Traore K, Thiam SM, Traoré SF, Cisse I, Mihigo J, Coulibaly MB, Dabitao D, Alifrangis M, Barry AE, Müller GC, Beier JC, Shaffer JG. A Decade of Progress Accelerating Malaria Control in Mali: Evidence from the West Africa International Center of Excellence for Malaria Research. Am J Trop Med Hyg 2022; 107:75-83. [PMID: 36228923 PMCID: PMC9662231 DOI: 10.4269/ajtmh.21-1309] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 07/06/2022] [Indexed: 11/07/2022] Open
Abstract
This article highlights over a decade of signature achievements by the West Africa International Centers for Excellence in Malaria Research (WA-ICEMR) and its partners toward guiding malaria prevention and control strategies. Since 2010, the WA-ICEMR has performed longitudinal studies to monitor and assess malaria control interventions with respect to space-time patterns, vector transmission indicators, and drug resistance markers. These activities were facilitated and supported by the Mali National Malaria Control Program. Research activities included large-scale active and passive surveillance and expanded coverage of universal long-lasting insecticide-treated bed nets and seasonal malaria chemoprevention (SMC). The findings revealed substantial declines in malaria occurrence after the scale-up of control interventions in WA-ICEMR study sites. WA-ICEMR studies showed that SMC using sulfadoxine-pyrimethamine plus amodiaquine was highly effective in preventing malaria among children under 5 years of age. An alternative SMC regimen (dihydroartemisinin plus piperaquine) was shown to be potentially more effective and provided advantages for acceptability and compliance over the standard SMC regimen. Other findings discussed in this article include higher observed multiplicity of infection rates for malaria in historically high-endemic areas, continued antimalarial drug sensitivity to Plasmodium falciparum, high outdoor malaria transmission rates, and increased insecticide resistance over the past decade. The progress achieved by the WA-ICEMR and its partners highlights the critical need for maintaining current malaria control interventions while developing novel strategies to disrupt malaria transmission. Enhanced evaluation of these strategies through research partnerships is particularly needed in the wake of reported artemisinin resistance in Southeast Asia and East Africa.
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Affiliation(s)
- Seydou Doumbia
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Nafomon Sogoba
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamadou Diakite
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamoudou Toure
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Moussa Keita
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Drissa Konaté
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sory I. Diawara
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ayouba Diarra
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Daouda Sanogo
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Fousseyni Kane
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Seidina A. S. Diakite
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Karim Traore
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sidibé M’Baye Thiam
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sékou F. Traoré
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Idrissa Cisse
- National Malaria Control Program, Ministry of Health, Bamako, Mali
| | - Jules Mihigo
- U.S. President’s Malaria Initiative, United States Agency for International Development Office, Bamako, Mali
| | - Mamadou B. Coulibaly
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Djeneba Dabitao
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Michael Alifrangis
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | | | - Günter C. Müller
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - John C. Beier
- Miller School of Medicine, University of Miami, Miami, Florida
| | - Jeffrey G. Shaffer
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana
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4
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Touré M, Keita M, Kané F, Sanogo D, Kanté S, Konaté D, Diarra A, Sogoba N, Coulibaly MB, Traoré SF, Alifrangis M, Diakité M, Shaffer JG, Krogstad DJ, Doumbia S. Trends in malaria epidemiological factors following the implementation of current control strategies in Dangassa, Mali. Malar J 2022; 21:65. [PMID: 35197053 PMCID: PMC8867639 DOI: 10.1186/s12936-022-04058-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 01/21/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Over the past decade, three strategies have reduced severe malaria cases and deaths in endemic regions of Africa, Asia and the Americas, specifically: (1) artemisinin-based combination therapy (ACT); (2) insecticide-treated bed nets (ITNs); and, (3) intermittent preventive treatment with sulfadoxine-pyrimethamine in pregnancy (IPTp). The rationale for this study was to examine communities in Dangassa, Mali where, in 2015, two additional control strategies were implemented: ITN universal coverage and seasonal malaria chemoprevention (SMC) among children under 5 years old. METHODS This was a prospective study based on a rolling longitudinal cohort of 1401 subjects participating in bi-annual smear surveys for the prevalence of asymptomatic Plasmodium falciparum infection and continuous surveillance for the incidence of human disease (uncomplicated malaria), performed in the years from 2012 to 2020. Entomological collections were performed to examine the intensity of transmission based on pyrethroid spray catches, human landing catches and enzyme-linked immunosorbent assay (ELISA) testing for circumsporozoite antigen. RESULTS A total of 1401 participants of all ages were enrolled in the study in 2012 after random sampling of households from the community census list. Prevalence of infection was extremely high in Dangassa, varying from 9.5 to 62.8% at the start of the rainy season and from 15.1 to 66.7% at the end of the rainy season. Likewise, the number of vectors per house, biting rates, sporozoites rates, and entomological inoculation rates (EIRs) were substantially greater in Dangassa. DISCUSSION The findings for this study are consistent with the progressive implementation of effective malaria control strategies in Dangassa. At baseline (2012-2014), prevalence of P. falciparum was above 60% followed by a significant year-to-year decease starting in 2015. Incidence of uncomplicated infection was greater among children < 5 years old, while asymptomatic infection was more frequent among the 5-14 years old. A significant decrease in EIR was also observed from 2015 to 2020. Likewise, vector density, sporozoite rates, and EIRs decreased substantially during the study period. CONCLUSION Efficient implementation of two main malaria prevention strategies in Dangassa substantially contribute to a reduction of both asymptomatic and symptomatic malaria from 2015 to 2020.
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Affiliation(s)
- Mahamoudou Touré
- West African International Center of Excellence for Malaria Research, Bamako, Mali. .,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali.
| | - Moussa Keita
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Fousseyni Kané
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Daouda Sanogo
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Salim Kanté
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Drissa Konaté
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Ayouba Diarra
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Nafomon Sogoba
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Mamadou B Coulibaly
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Sekou F Traoré
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Pharmacie (FAPH), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Michael Alifrangis
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Department of Immunology and Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mahamadou Diakité
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Pharmacie (FAPH), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Jeffrey G Shaffer
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Departments of Tropical Medicine and Biostatistics, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Donald J Krogstad
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Departments of Tropical Medicine and Biostatistics, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Seydou Doumbia
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Faculté de Médecine et d'Odonto-Stomatologie (FMOS), Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
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5
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Keïta M, Doumbia S, Sissoko I, Touré M, Diawara SI, Konaté D, Sodio AB, Traoré SF, Diakité M, Doumbia SO, Sogoba N, Krogstad DJ, Shaffer JG, Coulibaly MB. Indoor and outdoor malaria transmission in two ecological settings in rural Mali: implications for vector control. Malar J 2021; 20:127. [PMID: 33663515 PMCID: PMC7931590 DOI: 10.1186/s12936-021-03650-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 02/15/2021] [Indexed: 11/17/2022] Open
Abstract
Background Implementation and upscale of effective malaria vector control strategies necessitates understanding the multi-factorial aspects of transmission patterns. The primary aims of this study are to determine the vector composition, biting rates, trophic preference, and the overall importance of distinguishing outdoor versus indoor malaria transmission through a study at two communities in rural Mali. Methods Mosquito collection was carried out between July 2012 and June 2016 at two rural Mali communities (Dangassa and Koïla Bamanan) using pyrethrum spray-catch and human landing catch approaches at both indoor and outdoor locations. Species of Anopheles gambiae complex were identified by polymerase chain reaction (PCR). Enzyme-Linked -Immuno-Sorbent Assay (ELISA) were used to determine the origin of mosquito blood meals and presence of Plasmodium falciparum sporozoite infections. Results A total of 11,237 An. gambiae sensu lato (s.l.) were collected during the study period (5239 and 5998 from the Dangassa and Koïla Bamanan sites, respectively). Of the 679 identified by PCR in Dangassa, Anopheles coluzzii was the predominant species with 91.4% of the catch followed by An. gambiae (8.0%) and Anopheles arabiensis (0.6%). At the same time in Koïla Bamanan, of the 623 An. gambiae s.l., An. coluzzii accounted for 99% of the catch, An. arabiensis 0.8% and An. gambiae 0.2%. Human Blood Index (HBI) measures were significantly higher in Dangassa (79.4%; 95% Bayesian credible interval (BCI) [77.4, 81.4]) than in Koïla Bamanan (15.9%; 95% BCI [14.7, 17.1]). The human biting rates were higher during the second half of the night at both sites. In Dangassa, the sporozoite rate was comparable between outdoor and indoor mosquito collections. For outdoor collections, the sporozoite positive rate was 3.6% (95% BCI [2.1–4.3]) and indoor collections were 3.1% (95% BCI [2.4–5.0]). In Koïla Bamanan, the sporozoite rate was higher indoors at 4.3% (95% BCI [2.7–6.3]) compared with outdoors at 2.4% (95% BCI [1.1–4.2]). In Dangassa, corrected entomological inoculation rates (cEIRs) using HBI were 13.74 [95% BCI 9.21–19.14] infective bites/person/month (ib/p/m) at indoor, and 18.66 [95% BCI 12.55–25.81] ib/p/m at outdoor. For Koïla Bamanan, cEIRs were 1.57 [95% BCI 2.34–2.72] ib/p/m and 0.94 [95% BCI 0.43–1.64] ib/p/m for indoor and outdoor, respectively. EIRs were significantly higher at the Dangassa site than the Koïla Bamanan site. Conclusion The findings in this work may indicate the occurrence of active, outdoor residual malaria transmission is comparable to indoor transmission in some geographic settings. The high outdoor transmission patterns observed here highlight the need for additional strategies to combat outdoor malaria transmission to complement traditional indoor preventive approaches such as long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) which typically focus on resting mosquitoes.
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Affiliation(s)
- Moussa Keïta
- West African International Center of Excellence for Malaria Research, Bamako, Mali. .,Malaria Research and Training Center, Bamako, Mali. .,Faculty of Medicine and Odonto Stomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali. .,Faculty of Science and Techniques, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.
| | - Sidy Doumbia
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Ibrahim Sissoko
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Mahamoudou Touré
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Sory Ibrahim Diawara
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Drissa Konaté
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Ambièlè Bernard Sodio
- Faculty of Science and Techniques, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sekou F Traoré
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Mahamadou Diakité
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
| | - Seydou O Doumbia
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali.,Faculty of Medicine and Odonto Stomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Nafomon Sogoba
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali.,Faculty of Medicine and Odonto Stomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Donald J Krogstad
- School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, New Orleans, LA, 70112, USA
| | - Jeffrey G Shaffer
- School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, New Orleans, LA, 70112, USA
| | - Mamadou B Coulibaly
- West African International Center of Excellence for Malaria Research, Bamako, Mali.,Malaria Research and Training Center, Bamako, Mali
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