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Hilton ER, Tougri G, Camara T, Pagabelem A, Ouedraogo JB, Millar J, Jacob D, Kone A, Diouf M, Belemvire A, Burnett S. An observational analysis of the impact of indoor residual spraying in two distinct contexts of Burkina Faso. Malar J 2024; 23:229. [PMID: 39095782 PMCID: PMC11295511 DOI: 10.1186/s12936-024-05054-2] [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: 08/08/2023] [Accepted: 07/20/2024] [Indexed: 08/04/2024] Open
Abstract
BACKGROUND Indoor residual spraying (IRS) is a cornerstone malaria control intervention in Burkina Faso. From 2018 to 2021, non-pyrethroid IRS was implemented annually in two regions of Burkina Faso with distinct malaria transmission patterns, concurrently with annual seasonal malaria chemoprevention (SMC), and a mass insecticide-treated net (ITN) distribution in 2019. METHODS A retrospective quasi-experimental approach was used to evaluate the impact of the 2018, 2020, and 2021 IRS campaigns on routinely reported confirmed malaria case incidence at health facilities. The 2019 campaign was excluded due to lack of data reporting during a health sector strike. Controlled interrupted time series models were fit to detect changes in level and trend in malaria case incidence rates following each IRS campaign when compared to the baseline period 24-months before IRS. IRS districts Solenzo (Sudano-Sahelien climate), and Kampti (tropical climate) were compared with neighbouring control districts and the analyses were stratified by region. Modelled health facility catchment population estimates based on travel time to health facilities and weighted by non-malaria outpatient visits were used as an offset. The study period encompassed July 2016 through June 2022, excluding July 2018 to June 2019. RESULTS District-level population and structure coverage achieved by IRS campaigns was greater than 85% in 2018, 2020, and 2021 in Solenzo and Kampti. In Solenzo a significant difference in malaria case incidence rates was detected after the 2018 campaign (IRR = 0.683; 95% CI 0.564-0.827) when compared to the control district. The effect was not detected following the 2020 or 2021 IRS campaigns. In Kampti, estimated malaria incidence rates were between 36 and 38% lower than in the control district following all three IRS campaigns compared to the baseline period. CONCLUSIONS Implementation of IRS in Kampti, a tropical region of Burkina Faso, appeared to have a consistent significant beneficial impact on malaria case rates. An initial positive impact in Solenzo after the first IRS campaign was not sustained in the successive evaluated IRS campaigns. This study points to a differential effect of IRS in different malaria transmission settings and in combination with ITN and SMC implementation.
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Affiliation(s)
- Emily R Hilton
- PMI VectorLink Project, PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA.
| | - Gauthier Tougri
- Programme National de Lutte Contre le Paludisme, Ouagadougou, Burkina Faso
| | - Tiécoura Camara
- Programme National de Lutte Contre le Paludisme, Ouagadougou, Burkina Faso
| | - Ardjouma Pagabelem
- Programme National de Lutte Contre le Paludisme, Ouagadougou, Burkina Faso
| | | | - Justin Millar
- PMI VectorLink Project, PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA
| | - Djenam Jacob
- PMI VectorLink Project, Abt Associates, Rockville, MD, USA
| | - Adama Kone
- PMI VectorLink Project, Abt Associates, Rockville, MD, USA
| | - Mame Diouf
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Ouagadougou, Burkina Faso
| | - Allison Belemvire
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA
| | - Sarah Burnett
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA
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2
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Villena OC, Arab A, Lippi CA, Ryan SJ, Johnson LR. Influence of environmental, geographic, socio-demographic, and epidemiological factors on presence of malaria at the community level in two continents. Sci Rep 2024; 14:16734. [PMID: 39030306 PMCID: PMC11271557 DOI: 10.1038/s41598-024-67452-5] [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: 05/10/2024] [Accepted: 07/11/2024] [Indexed: 07/21/2024] Open
Abstract
The interactions of environmental, geographic, socio-demographic, and epidemiological factors in shaping mosquito-borne disease transmission dynamics are complex and changeable, influencing the abundance and distribution of vectors and the pathogens they transmit. In this study, 27 years of cross-sectional malaria survey data (1990-2017) were used to examine the effects of these factors on Plasmodium falciparum and Plasmodium vivax malaria presence at the community level in Africa and Asia. Monthly long-term, open-source data for each factor were compiled and analyzed using generalized linear models and classification and regression trees. Both temperature and precipitation exhibited unimodal relationships with malaria, with a positive effect up to a point after which a negative effect was observed as temperature and precipitation increased. Overall decline in malaria from 2000 to 2012 was well captured by the models, as was the resurgence after that. The models also indicated higher malaria in regions with lower economic and development indicators. Malaria is driven by a combination of environmental, geographic, socioeconomic, and epidemiological factors, and in this study, we demonstrated two approaches to capturing this complexity of drivers within models. Identifying these key drivers, and describing their associations with malaria, provides key information to inform planning and prevention strategies and interventions to reduce malaria burden.
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Affiliation(s)
- Oswaldo C Villena
- The Earth Commons Institute, Georgetown University, Washington, DC, 20057, USA.
| | - Ali Arab
- Department of Mathematics and Statistics, Georgetown University, Washington, DC, 20057, USA
| | - Catherine A Lippi
- Department of Geography, University of Florida, Gainesville, FL, 32611, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Sadie J Ryan
- Department of Geography, University of Florida, Gainesville, FL, 32611, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
- School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Leah R Johnson
- Department of Statistics, Virginia Tech, Blacksburg, VA, 24061, USA
- Computational Modeling and Data Analytics, Virginia Tech, Blacksburg, VA, 24061, USA
- Department of Biology, Virginia Tech, Blacksburg, VA, 24061, USA
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Nagi SC, Lucas ER, Egyir-Yawson A, Essandoh J, Dadzie S, Chabi J, Djogbénou LS, Medjigbodo AA, Edi CV, Ketoh GK, Koudou BG, Ashraf F, Clarkson CS, Miles A, Weetman D, Donnelly MJ. Parallel Evolution in Mosquito Vectors-A Duplicated Esterase Locus is Associated With Resistance to Pirimiphos-methyl in Anopheles gambiae. Mol Biol Evol 2024; 41:msae140. [PMID: 38985692 PMCID: PMC11267716 DOI: 10.1093/molbev/msae140] [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: 02/14/2024] [Revised: 05/02/2024] [Accepted: 05/29/2024] [Indexed: 07/12/2024] Open
Abstract
The primary control methods for the African malaria mosquito, Anopheles gambiae, are based on insecticidal interventions. Emerging resistance to these compounds is therefore of major concern to malaria control programs. The organophosphate (OP), pirimiphos-methyl, is a relatively new chemical in the vector control armory but is now widely used in indoor-residual spray campaigns. While generally effective, phenotypic resistance has developed in some areas in malaria vectors. Here, we used a population genomic approach to identify novel mechanisms of resistance to pirimiphos-methyl in A. gambiae s.l mosquitoes. In multiple populations, we found large and repeated signals of selection at a locus containing a cluster of detoxification enzymes, some of whose orthologs are known to confer resistance to OPs in Culex pipiens. Close examination revealed a pair of alpha-esterases, Coeae1f and Coeae2f, and a complex and diverse pattern of haplotypes under selection in A. gambiae, A. coluzzii and A. arabiensis. As in C. pipiens, copy number variants have arisen at this locus. We used diplotype clustering to examine whether these signals arise from parallel evolution or adaptive introgression. Using whole-genome sequenced phenotyped samples, we found that in West Africa, a copy number variant in A. gambiae is associated with resistance to pirimiphos-methyl. Overall, we demonstrate a striking example of contemporary parallel evolution which has important implications for malaria control programs.
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Affiliation(s)
- Sanjay C Nagi
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Eric R Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | | | - John Essandoh
- Department of Biomedical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Samuel Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Joseph Chabi
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Luc S Djogbénou
- Laboratory of Infectious Vector Borne Diseases, Tropical Infectious Diseases Research Center (TIDRC), Université d’Abomey-Calavi (UAC), 01 B.P. 526 Cotonou, Benin
| | - Adandé A Medjigbodo
- Laboratory of Infectious Vector Borne Diseases, Tropical Infectious Diseases Research Center (TIDRC), Université d’Abomey-Calavi (UAC), 01 B.P. 526 Cotonou, Benin
| | - Constant V Edi
- Research and Development Department, Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan, Côte d’Ivoire
| | - Guillaume K Ketoh
- Department of Zoology, Faculty of Sciences, Laboratory of Ecology and Ecotoxicology, Université de Lomé, 01 B.P. 1515 Lomé, Togo
| | - Benjamin G Koudou
- Research and Development Department, Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan, Côte d’Ivoire
| | - Faisal Ashraf
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Chris S Clarkson
- Wellcome Sanger Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1RQ, UK
| | - Alistair Miles
- Wellcome Sanger Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1RQ, UK
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
- Wellcome Sanger Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1RQ, UK
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4
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Lynd A, Gonahasa S, Staedke SG, Oruni A, Maiteki-Sebuguzi C, Hancock PA, Knight E, Dorsey G, Opigo J, Yeka A, Katureebe A, Kyohere M, Hemingway J, Kamya MR, McDermott D, Lucas ER, Donnelly MJ. LLIN Evaluation in Uganda Project (LLINEUP)-effects of a vector control trial on Plasmodium infection prevalence and genotypic markers of insecticide resistance in Anopheles vectors from 48 districts of Uganda. Sci Rep 2024; 14:14488. [PMID: 38914669 PMCID: PMC11196729 DOI: 10.1038/s41598-024-65050-z] [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: 12/07/2023] [Accepted: 06/17/2024] [Indexed: 06/26/2024] Open
Abstract
Pyrethroid bednets treated with the synergist piperonyl butoxide (PBO) offer the possibility of improved vector control in mosquito populations with metabolic resistance. In 2017-2019, we conducted a large-scale, cluster-randomised trial (LLINEUP) to evaluate long-lasting insecticidal nets (LLINs) treated with a pyrethroid insecticide plus PBO (PBO LLINs), as compared to conventional, pyrethroid-only LLINs across 104 health sub-districts (HSDs) in Uganda. In LLINEUP, and similar trials in Tanzania, PBO LLINs were found to provide greater protection against malaria than conventional LLINs, reducing parasitaemia and vector density. In the LLINEUP trial, we conducted cross-sectional household entomological surveys at baseline and then every 6 months for two years, which we use here to investigate longitudinal changes in mosquito infection rate and genetic markers of resistance. Overall, 5395 female Anopheles mosquitoes were collected from 5046 households. The proportion of mosquitoes infected (PCR-positive) with Plasmodium falciparum did not change significantly over time, while infection with non-falciparum malaria decreased in An. gambiae s.s., but not An. funestus. The frequency of genetic markers associated with pyrethroid resistance increased significantly over time, but the rate of change was not different between the two LLIN types. The knock-down resistance (kdr) mutation Vgsc-995S declined over time as Vgsc-995F, the alternative resistance mutation at this codon, increased. Vgsc-995F appears to be spreading into Uganda. Distribution of LLINs in Uganda was previously found to be associated with reductions in parasite prevalence and vector density, but here we show that the proportion of infective mosquitoes remained stable across both PBO and non-PBO LLINs, suggesting that the potential for transmission persisted. The increased frequency of markers of pyrethroid resistance indicates that LLIN distribution favoured the evolution of resistance within local vectors and highlights the potential benefits of resistance management strategies.Trial registration: This study is registered with ISRCTN, ISRCTN17516395. Registered 14 February 2017, http://www.isrctn.com/ISRCTN17516395 .
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Affiliation(s)
- Amy Lynd
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Samuel Gonahasa
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Sarah G Staedke
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Ambrose Oruni
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | | | | | - Erin Knight
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Grant Dorsey
- University of California, San Francisco, San Francisco, CA, 94110, USA
| | | | - Adoke Yeka
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Agaba Katureebe
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Mary Kyohere
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Janet Hemingway
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
- Department of Medicine, Makerere University, Kampala, Uganda
| | - Daniel McDermott
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Eric R Lucas
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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Gonahasa S, Nassali M, Maiteki-Sebuguzi C, Namuganga JF, Opigo J, Nabende I, Okiring J, Epstein A, Snyman K, Nankabirwa JI, Kamya MR, Dorsey G, Staedke SG. LLIN evaluation in Uganda project (LLINEUP2): association between housing construction and malaria burden in 32 districts. Malar J 2024; 23:190. [PMID: 38886782 PMCID: PMC11181653 DOI: 10.1186/s12936-024-05012-y] [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: 02/21/2024] [Accepted: 06/08/2024] [Indexed: 06/20/2024] Open
Abstract
BACKGROUND Well-built housing limits mosquito entry and can reduce malaria transmission. The association between community-level housing and malaria burden in Uganda was assessed using data from randomly selected households near 64 health facilities in 32 districts. METHODS Houses were classified as 'improved' (synthetic walls and roofs, eaves closed or absent) or 'less-improved' (all other construction). Associations between housing and parasitaemia were made using mixed effects logistic regression (individual-level) and multivariable fractional response logistic regression (community-level), and between housing and malaria incidence using multivariable Poisson regression. RESULTS Between November 2021 and March 2022, 4.893 children aged 2-10 years were enrolled from 3.518 houses; of these, 1.389 (39.5%) were classified as improved. Children living in improved houses had 58% lower odds (adjusted odds ratio = 0.42, 95% CI 0.33-0.53, p < 0.0001) of parasitaemia than children living in less-improved houses. Communities with > 67% of houses improved had a 63% lower parasite prevalence (adjusted prevalence ratio 0.37, 95% CI 0.19-0.70, p < 0.0021) and 60% lower malaria incidence (adjusted incidence rate ratio 0.40, 95% CI 0.36-0.44, p < 0.0001) compared to communities with < 39% of houses improved. CONCLUSIONS Improved housing was strongly associated with lower malaria burden across a range of settings in Uganda and should be utilized for malaria control.
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Affiliation(s)
- Samuel Gonahasa
- Infectious Diseases Research Collaboration, Kampala, Uganda.
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Martha Nassali
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Catherine Maiteki-Sebuguzi
- Infectious Diseases Research Collaboration, Kampala, Uganda
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | | | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Isaiah Nabende
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Jaffer Okiring
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Adrienne Epstein
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Katherine Snyman
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Global Health and Development, London School of Hygiene & Tropical Medicine, London, UK
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, Kampala, Uganda
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Sarah G Staedke
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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Mensah EA, Gyasi SO, Nsubuga F, Alali WQ. A proposed One Health approach to control yellow fever outbreaks in Uganda. ONE HEALTH OUTLOOK 2024; 6:9. [PMID: 38783349 PMCID: PMC11119388 DOI: 10.1186/s42522-024-00103-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 04/26/2024] [Indexed: 05/25/2024]
Abstract
Yellow Fever (YF) is an acute viral hemorrhagic disease. Uganda is located within the Africa YF belt. Between 2019 and 2022, the Ugandan Health Authorities reported at least one outbreak of YF annually with an estimated 892 suspected cases, on average per year. The persistent recurrence of this disease raises significant concerns about the efficacy of current response strategies and prevention approaches. YF has been recognized as a One Health issue due to its interrelatedness with the animal and environmental domains. Monkeys have been recognized as the virus primary reservoir. The YF virus is transmitted through bites of infected Aedes or Haemagogus species mosquitoes between monkeys and humans. Human activities, monkey health, and environmental health issues (e.g., climate change and land use) impact YF incidence in Uganda. Additionally, disease control programs for other tropical diseases, such as mosquitoes control programs for malaria, impact YF incidence.This review adopts the One Health approach to highlight the limitations in the existing segmented YF control and prevention strategies in Uganda, including the limited health sector surveillance, the geographically localized outbreak response efforts, the lack of a comprehensive vaccination program, the limited collaboration and communication among relevant national and international agencies, and the inadequate vector control practices. Through a One Health approach, we propose establishing a YF elimination taskforce. This taskforce would oversee coordination of YF elimination initiatives, including implementing a comprehensive surveillance system, conducting mass YF vaccination campaigns, integrating mosquito management strategies, and enhancing risk communication. It is anticipated that adopting the One Health approach will reduce the risk of YF incidence and outbreaks.
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Affiliation(s)
- Emmanuel Angmorteh Mensah
- Department of Biostatistics & Epidemiology, College of Public Health, East Tennessee State University, Johnson City, TN, USA
| | - Samuel Ofori Gyasi
- Department of Immunization, Vaccines and Biologicals, World Health Organization Country Office, Kampala, Uganda
| | - Fred Nsubuga
- Division of Immunization and Vaccines, Ministry of Health, Kampala, Uganda
| | - Walid Q Alali
- Department of Biostatistics & Epidemiology, College of Public Health, East Tennessee State University, Johnson City, TN, USA.
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Oruni A, Lynd A, Njoroge H, Onyige I, van’t Hof AE, Matovu E, Donnelly MJ. Pyrethroid resistance and gene expression profile of a new resistant An. gambiae colony from Uganda reveals multiple resistance mechanisms and overexpression of Glutathione-S-Transferases linked to survival of PBO-pyrethroid combination. Wellcome Open Res 2024; 9:13. [PMID: 38813466 PMCID: PMC11134160 DOI: 10.12688/wellcomeopenres.19404.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2024] [Indexed: 05/31/2024] Open
Abstract
Background The effectiveness of long-lasting insecticidal nets (LLINs) are being threatened by growing resistance to pyrethroids. To restore their efficacy, a synergist, piperonyl butoxide (PBO) which inhibits cytochrome P450s has been incorporated into pyrethroid treated nets. A trial of PBO-LLINs was conducted in Uganda from 2017 and we attempted to characterize mechanisms of resistance that could impact intervention efficacy. Methods We established an Anopheles gambiae s.s colony in 2018 using female mosquitoes collected from Busia district in eastern Uganda. We first assessed the phenotypic resistance profile of this colony using WHO tube and net assays using a deltamethrin dose-response approach. The Busia colony was screened for known resistance markers and RT-qPCR targeting 15 genes previously associated with insecticide resistance was performed. Results The Busia colony had very high resistance to deltamethrin, permethrin and DDT. In addition, the colony had moderate resistance to alpha-cypermethrin and lambda-cyhalothrin but were fully susceptible to bendiocarb and fenitrothion. Exposure to PBO in combination with permethrin and deltamethrin resulted in higher mortality rates in both net and tube assays, with a higher mortality observed in net assays than tube assays. The kdr marker, Vgsc-995S was at very high frequency (91.7-98.9%) whilst the metabolic markers Coeae1d and Cyp4j5-L43F were at very low (1.3% - 11.5%) and moderate (39.5% - 44.7%) frequencies respectively. Our analysis showed that gene expression pattern in mosquitoes exposed to deltamethrin, permethrin or DDT only were similar in comparison to the susceptible strain and there was significant overexpression of cytochrome P450s, glutathione-s-transferases (GSTs) and carboxyl esterases (COEs). However, mosquitoes exposed to both PBO and pyrethroid strikingly and significantly only overexpressed closely related GSTs compared to unexposed mosquitoes while major cytochrome P450s were underexpressed. Conclusions The high levels of pyrethroid resistance observed in Busia appears associated with a wide range of metabolic gene families.
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Affiliation(s)
- Ambrose Oruni
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Central Region, Uganda
| | - Amy Lynd
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
| | - Harun Njoroge
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Ismail Onyige
- Infectious Diseases Research Collaboration, Kampala, Central Region, Uganda
| | - Arjen E. van’t Hof
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
| | - Enock Matovu
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Central Region, Uganda
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
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8
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Hilton ER, Gning-Cisse N, Assi A, Eyakou M, Koffi J, Gnakou B, Kouassi B, Flatley C, Chabi J, Gbalegba C, Alex Aimain S, Yah Kokrasset C, Antoine Tanoh M, N'Gotta S, Yao O, Egou Assi H, Konan P, Davis K, Constant E, Belemvire A, Yepassis-Zembrou P, Zinzindohoue P, Kouadio B, Burnett S. Reduction of malaria case incidence following the introduction of clothianidin-based indoor residual spraying in previously unsprayed districts: an observational analysis using health facility register data from Côte d'Ivoire, 2018-2022. BMJ Glob Health 2024; 9:e013324. [PMID: 38519096 PMCID: PMC10961507 DOI: 10.1136/bmjgh-2023-013324] [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: 07/05/2023] [Accepted: 12/21/2023] [Indexed: 03/24/2024] Open
Abstract
BACKGROUND Indoor residual spraying (IRS) using neonicotinoid-based insecticides (clothianidin and combined clothianidin with deltamethrin) was deployed in two previously unsprayed districts of Côte d'Ivoire in 2020 and 2021 to complement standard pyrethroid insecticide-treated nets. This retrospective observational study uses health facility register data to assess the impact of IRS on clinically reported malaria case incidence. METHODS Health facility data were abstracted from consultation registers for the period September 2018 to April 2022 in two IRS districts and two control districts that did not receive IRS. Malaria cases reported by community health workers (CHWs) were obtained from district reports and District Health Information Systems 2. Facilities missing complete data were excluded. Controlled interrupted time series models were used to estimate the effect of IRS on monthly all-ages population-adjusted confirmed malaria cases and cases averted by IRS. Models controlled for transmission season, precipitation, vegetation, temperature, proportion of cases reported by CHWs, proportion of tested out of suspected cases and non-malaria outpatient visits. RESULTS An estimated 10 988 (95% CI 5694 to 18 188) malaria cases were averted in IRS districts the year following the 2020 IRS campaign, representing a 15.9% reduction compared with if IRS had not been deployed. Case incidence in IRS districts dropped by 27.7% (incidence rate ratio (IRR) 0.723, 95% CI 0.592 to 0.885) the month after the campaign. In the 8 months after the 2021 campaign, 14 170 (95% CI 13 133 to 15 025) estimated cases were averted, a 24.7% reduction, and incidence in IRS districts dropped by 37.9% (IRR 0.621, 95% CI 0.462 to 0.835) immediately after IRS. Case incidence in control districts did not change following IRS either year (p>0.05) and the difference in incidence level change between IRS and control districts was significant both years (p<0.05). CONCLUSION Deployment of clothianidin-based IRS was associated with a reduction in malaria case rates in two districts of Côte d'Ivoire following IRS deployment in 2020 and 2021.
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Affiliation(s)
| | | | - Auguste Assi
- PMI VectorLink Project, Abt Associates, Abidjan, Côte d'Ivoire
| | - Mathieu Eyakou
- PMI VectorLink Project, Abt Associates, Abidjan, Côte d'Ivoire
| | - John Koffi
- PMI VectorLink Project, Abt Associates, Abidjan, Côte d'Ivoire
| | | | - Bernard Kouassi
- PMI VectorLink Project, Abt Associates, Abidjan, Côte d'Ivoire
| | - Cecilia Flatley
- PMI VectorLink Project, Abt Associates, Rockville, Maryland, USA
| | - Joseph Chabi
- PMI VectorLink Project, Abt Associates, Rockville, Maryland, USA
| | - Constant Gbalegba
- Programme National de Lutte Contre le Paludisme, Abidjan, Côte d'Ivoire
| | - Serge Alex Aimain
- Programme National de Lutte Contre le Paludisme, Abidjan, Côte d'Ivoire
| | | | - Mea Antoine Tanoh
- Programme National de Lutte Contre le Paludisme, Abidjan, Côte d'Ivoire
| | - Sylvain N'Gotta
- Programme National de Lutte Contre le Paludisme, Abidjan, Côte d'Ivoire
| | - Octavie Yao
- Programme National de Lutte Contre le Paludisme, Abidjan, Côte d'Ivoire
| | - Hughes Egou Assi
- Direction de l'Informatique et de l'Information Sanitaire, Abidjan, Côte d'Ivoire
| | - Philomène Konan
- Direction de l'Informatique et de l'Information Sanitaire, Abidjan, Côte d'Ivoire
| | - Kelly Davis
- PMI VectorLink Project, PATH, Washington, District of Columbia, USA
| | - Edi Constant
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Allison Belemvire
- US President's Malaria Initiative, US Agency for International Development, Washington, District of Columbia, USA
| | - Patricia Yepassis-Zembrou
- U.S. President's Malaria Initiative, Centers for Disease Control and Prevention, Abidjan, Côte d'Ivoire
| | - Pascal Zinzindohoue
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Abidjan, Côte d'Ivoire
| | - Blaise Kouadio
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Abidjan, Côte d'Ivoire
| | - Sarah Burnett
- PMI VectorLink Project, PATH, Washington, District of Columbia, USA
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9
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Kamya MR, Nankabirwa JI, Arinaitwe E, Rek J, Zedi M, Maiteki-Sebuguzi C, Opigo J, Staedke SG, Oruni A, Donnelly MJ, Greenhouse B, Briggs J, Krezanoski PJ, Bousema T, Rosenthal PJ, Olwoch P, Jagannathan P, Rodriguez-Barraquer I, Dorsey G. Dramatic resurgence of malaria after 7 years of intensive vector control interventions in Eastern Uganda. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.03.15.24304352. [PMID: 38559091 PMCID: PMC10980127 DOI: 10.1101/2024.03.15.24304352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Background Tororo District, Uganda experienced a dramatic decrease in malaria burden from 2015-19 following 5 years of indoor residual spraying (IRS) with carbamate (Bendiocarb) and then organophosphate (Actellic) insecticides. However, a marked resurgence occurred in 2020, which coincided with a change to a clothianidin-based IRS formulations (Fludora Fusion/SumiShield). To quantify the magnitude of the resurgence, investigate causes, and evaluate the impact of a shift back to IRS with Actellic in 2023, we assessed changes in malaria metrics in regions within and near Tororo District. Methods Malaria surveillance data from Nagongera Health Center, Tororo District was included from 2011-2023. In addition, a cohort of 667 residents from 84 houses was followed from August 2020 through September 2023 from an area bordering Tororo and neighboring Busia District, where IRS has never been implemented. Cohort participants underwent passive surveillance for clinical malaria and active surveillance for parasitemia every 28 days. Mosquitoes were collected in cohort households every 2 weeks using CDC light traps. Female Anopheles were speciated and tested for sporozoites and phenotypic insecticide resistance. Temporal comparisons of malaria metrics were stratified by geographic regions. Findings At Nagongera Health Center average monthly malaria cases varied from 419 prior to implementation of IRS; to 56 after 5 years of IRS with Bendiocarb and Actellic; to 1591 after the change in IRS to Fludora Fusion/SumiShield; to 155 after a change back to Actellic. Among cohort participants living away from the border in Tororo, malaria incidence increased over 8-fold (0.36 vs. 2.97 episodes per person year, p<0.0001) and parasite prevalence increased over 4-fold (17% vs. 70%, p<0.0001) from 2021 to 2022 when Fludora Fusion/SumiShield was used. Incidence decreased almost 5-fold (2.97 vs. 0.70, p<0.0001) and prevalence decreased by 39% (70% vs. 43%, p<0.0001) after shifting back to Actellic. There was a similar pattern among those living near the border in Tororo, with increased incidence between 2021 and 2022 (0.93 vs. 2.40, p<0.0001) followed by a decrease after the change to Actellic (2.40 vs. 1.33, p<0.001). Among residents of Busia, malaria incidence did not change significantly over the 3 years of observation. Malaria resurgence in Tororo was temporally correlated with the replacement of An. gambiae s.s. by An. funestus as the primary vector, with a marked decrease in the density of An. funestus following the shift back to IRS with Actellic. In Busia, An. gambiae s.s. remained the primary vector throughout the observation period. Sporozoite rates were approximately 50% higher among An. funestus compared to the other common malaria vectors. Insecticide resistance phenotyping of An. funestus revealed high tolerance to clothianidin, but full susceptibility to Actellic. Conclusions A dramatic resurgence of malaria in Tororo was temporally associated with a change to clothianidin-based IRS formulations and emergence of An. funestus as the predominant vector. Malaria decreased after a shift back to IRS with Actellic. This study highlights the ability of malaria vectors to rapidly circumvent control efforts and the importance of high-quality surveillance systems to assess the impact of malaria control interventions and generate timely, actionable data.
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Affiliation(s)
- Moses R. Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- School of Medicine, Makerere University Kampala, Uganda
| | - Joaniter I. Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- School of Medicine, Makerere University Kampala, Uganda
| | | | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Maato Zedi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Catherine Maiteki-Sebuguzi
- Infectious Diseases Research Collaboration, Kampala, Uganda
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Sarah G. Staedke
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Ambrose Oruni
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Jessica Briggs
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Paul J. Krezanoski
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Netherlands
| | - Philip J. Rosenthal
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Peter Olwoch
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Prasanna Jagannathan
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, USA
| | | | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
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10
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Nagi SC, Lucas ER, Egyir-Yawson A, Essandoh J, Dadzie S, Chabi J, Djogbénou LS, Medjigbodo AA, Edi CV, Ketoh GK, Koudou BG, Ashraf F, Clarkson CS, Miles A, Weetman D, Donnelly MJ. Parallel evolution in mosquito vectors - a duplicated esterase locus is associated with resistance to pirimiphos-methyl in An. gambiae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.01.578361. [PMID: 38352547 PMCID: PMC10862845 DOI: 10.1101/2024.02.01.578361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
The primary control methods for the African malaria mosquito, Anopheles gambiae, are based on insecticidal interventions. Emerging resistance to these compounds is therefore of major concern to malaria control programmes. The organophosphate, pirimiphos-methyl, is a relatively new chemical in the vector control armoury but is now widely used in indoor residual spray campaigns. Whilst generally effective, phenotypic resistance has developed in some areas in malaria vectors. Here, we used a population genomic approach to identify novel mechanisms of resistance to pirimiphos-methyl in Anopheles gambiae s.l mosquitoes. In multiple populations, we found large and repeated signals of selection at a locus containing a cluster of detoxification enzymes, some of whose orthologs are known to confer resistance to organophosphates in Culex pipiens. Close examination revealed a pair of alpha-esterases, Coeae1f and Coeae2f, and a complex and diverse pattern of haplotypes under selection in An. gambiae, An. coluzzii and An. arabiensis. As in Cx. pipiens, copy number variation seems to play a role in the evolution of insecticide resistance at this locus. We used diplotype clustering to examine whether these signals arise from parallel evolution or adaptive introgression. Using whole-genome sequenced phenotyped samples, we found that in West Africa, a copy number variant in Anopheles gambiae is associated with resistance to pirimiphos-methyl. Overall, we demonstrate a striking example of contemporary parallel evolution which has important implications for malaria control programmes.
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Affiliation(s)
- Sanjay C. Nagi
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Eric R. Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | | | - John Essandoh
- Department of Biomedical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Samuel Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Joseph Chabi
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Luc S. Djogbénou
- Tropical Infectious Diseases Research Center (TIDRC), Université d’Abomey-Calavi (UAC), 01 B.P. 526 Cotonou, Benin
| | - Adandé A. Medjigbodo
- Tropical Infectious Diseases Research Center (TIDRC), Université d’Abomey-Calavi (UAC), 01 B.P. 526 Cotonou, Benin
| | - Constant V. Edi
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan, Côte d’Ivoire
| | - Guillaume K. Ketoh
- Laboratory of Ecology and Ecotoxicology, Department of Zoology, Faculty of Sciences, Université de Lomé, 01 B.P. 1515 Lomé, Togo
| | - Benjamin G. Koudou
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan, Côte d’Ivoire
| | - Faisal Ashraf
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Chris S. Clarkson
- Wellcome Sanger Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1RQ, UK
| | - Alistair Miles
- Wellcome Sanger Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1RQ, UK
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Wellcome Sanger Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1RQ, UK
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11
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Conrad MD, Asua V, Garg S, Giesbrecht D, Niaré K, Smith S, Namuganga JF, Katairo T, Legac J, Crudale RM, Tumwebaze PK, Nsobya SL, Cooper RA, Kamya MR, Dorsey G, Bailey JA, Rosenthal PJ. Evolution of Partial Resistance to Artemisinins in Malaria Parasites in Uganda. N Engl J Med 2023; 389:722-732. [PMID: 37611122 PMCID: PMC10513755 DOI: 10.1056/nejmoa2211803] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
BACKGROUND Partial resistance of Plasmodium falciparum to the artemisinin component of artemisinin-based combination therapies, the most important malaria drugs, emerged in Southeast Asia and now threatens East Africa. Partial resistance, which manifests as delayed clearance after therapy, is mediated principally by mutations in the kelch protein K13 (PfK13). Limited longitudinal data are available on the emergence and spread of artemisinin resistance in Africa. METHODS We performed annual surveillance among patients who presented with uncomplicated malaria at 10 to 16 sites across Uganda from 2016 through 2022. We sequenced the gene encoding kelch 13 (pfk13) and analyzed relatedness using molecular methods. We assessed malaria metrics longitudinally in eight Ugandan districts from 2014 through 2021. RESULTS By 2021-2022, the prevalence of parasites with validated or candidate resistance markers reached more than 20% in 11 of the 16 districts where surveillance was conducted. The PfK13 469Y and 675V mutations were seen in far northern Uganda in 2016-2017 and increased and spread thereafter, reaching a combined prevalence of 10 to 54% across much of northern Uganda, with spread to other regions. The 469F mutation reached a prevalence of 38 to 40% in one district in southwestern Uganda in 2021-2022. The 561H mutation, previously described in Rwanda, was first seen in southwestern Uganda in 2021, reaching a prevalence of 23% by 2022. The 441L mutation reached a prevalence of 12 to 23% in three districts in western Uganda in 2022. Genetic analysis indicated local emergence of mutant parasites independent of those in Southeast Asia. The emergence of resistance was observed predominantly in areas where effective malaria control had been discontinued or transmission was unstable. CONCLUSIONS Data from Uganda showed the emergence of partial resistance to artemisinins in multiple geographic locations, with increasing prevalence and regional spread over time. (Funded by the National Institutes of Health.).
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Affiliation(s)
- Melissa D Conrad
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Victor Asua
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Shreeya Garg
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - David Giesbrecht
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Karamoko Niaré
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Sawyer Smith
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Jane F Namuganga
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Thomas Katairo
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Jennifer Legac
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Rebecca M Crudale
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Patrick K Tumwebaze
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Samuel L Nsobya
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Roland A Cooper
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Moses R Kamya
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Grant Dorsey
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Jeffrey A Bailey
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Philip J Rosenthal
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
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12
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Lynd A, Gonahasa S, Staedke SG, Oruni A, Maiteki-Sebuguzi C, Hancock P, Knight E, Dorsey G, Opigo J, Yeka A, Katureebe A, Kyohere M, Hemingway J, Kamya MR, McDermott D, Lucas ER, Donnelly MJ. LLIN Evaluation in Uganda Project (LLINEUP) - Plasmodium infection prevalence and genotypic markers of insecticide resistance in Anopheles vectors from 48 districts of Uganda. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.07.31.23293323. [PMID: 37577716 PMCID: PMC10418296 DOI: 10.1101/2023.07.31.23293323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Background In 2017-2019, we conducted a large-scale, cluster-randomised trial (LLINEUP) to evaluate long-lasting insecticidal nets (LLINs) treated with a pyrethroid insecticide plus the synergist piperonyl butoxide (PBO LLINs), as compared to conventional, pyrethroid-only LLINs across 104 health sub-districts (HSDs) in Uganda. In LLINEUP, and similar trials in Tanzania, PBO LLINs were found to provide greater protection against malaria than conventional LLINs, reducing parasitaemia and vector density. In the LLINEUP trial, cross-sectional entomological surveys were carried out at baseline and then every 6 months for two years. In each survey, ten households per HSD were randomly selected for indoor household entomological collections. Results Overall, 5395 female Anopheles mosquitoes were collected from 5046 households. The proportion of mosquitoes infected with Plasmodium falciparum did not change significantly over time, while infection with non-falciparum malaria decreased in An. gambiae s.s, but not An. funestus. The frequency of genetic markers associated with pyrethroid resistance increased significantly over time, but the rate of change was not different between the two LLIN types. The knock-down resistance (kdr) mutation Vgsc-995S declined over time as Vgsc-995F, the alternative resistance mutation at this codon, increased. Vgsc-995F appears to be spreading into Uganda. Conclusions Distribution of LLINs in Uganda was associated with reductions in parasite prevalence and vector density, but the proportion of infective mosquitoes remained stable, suggesting that the potential for transmission persisted. The increased frequency of markers of pyrethroid resistance indicates that LLIN distribution favoured the evolution of resistance within local vectors and highlights the potential benefits of resistance management strategies.Trial registration:: This study is registered with ISRCTN, ISRCTN17516395. Registered 14 February 2017, http://www.isrctn.com/ISRCTN17516395.
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Affiliation(s)
- Amy Lynd
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Samuel Gonahasa
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Sarah G Staedke
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Ambrose Oruni
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | | | | | - Erin Knight
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Grant Dorsey
- University of California, San Francisco, San Francisco, CA 94110 USA
| | | | - Adoke Yeka
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Agaba Katureebe
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Mary Kyohere
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Janet Hemingway
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Moses R Kamya
- Makerere University College of Health Sciences
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Daniel McDermott
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Eric R Lucas
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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13
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Iga J, Ochaya S, Echodu R, Opiyo EA, Musiime AK, Nakamaanya A, Malinga GM. Sibling Species Composition and Susceptibility Status of Anopheles gambiae s.l. to Insecticides Used for Indoor Residual Spraying in Eastern Uganda. J Parasitol Res 2023; 2023:2225233. [PMID: 37469527 PMCID: PMC10352534 DOI: 10.1155/2023/2225233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 06/09/2023] [Accepted: 06/22/2023] [Indexed: 07/21/2023] Open
Abstract
Background Malaria remains one of the most critical disease causing morbidity and mortality in Uganda. Indoor residual spraying (IRS) and the use of insecticide-treated bed nets are currently the predominant malaria vector control interventions. However, the emergence and spread of insecticide resistance among malaria vectors threaten the continued effectiveness of these interventions to control the disease, particularly in high transmission areas. To inform decisions on vector control, the current study evaluated the Anopheles malaria vector species and their susceptibility levels to 0.1% bendiocarb and 0.25% pirimiphos-methyl insecticides used in IRS intervention program in Namutumba district, Eastern Uganda. Methods Anopheles larvae were collected between March and May 2017 from different breeding sites in the parishes of Nsinze and Nawaikona in Nsinze sub-county and reared to adults to assess the susceptibility status of populations in the study area. Mosquitoes were identified using morphological keys and species-specific polymerase chain reaction (PCR) assays. Susceptibility tests were conducted on 2- to 5-day-old non-blood-fed adult female Anopheles that emerged using insecticide-impregnated papers with 0.1% bendiocarb and 0.25% pirimiphos-methyl following standard World Health Organization (WHO) insecticide susceptibility bioassays. A Log-probit regression model was used to derive the knock-down rates for 50% and 95% of exposed mosquitoes. Results A total of 700 mosquito larvae were collected from different breeding sites. Morphological identification showed that 500 individuals that emerged belonged to Anopheles gambiae sensu lato (s.l.), the main malaria vector. The PCR results showed that the dominant sibling species under the A. gambiae complex was Anopheles arabiensis 99.5% (395/397). WHO bioassay tests revealed that the population of mosquitoes exhibited high levels of susceptibility (24-hour post-exposure mortality 98-100%) to both insecticides tested. The median knock-down time, KDT50, ranged from 6.6 to 81.4 minutes, while the KDT95 ranged from 21.6 to 118.9 minutes for 0.25% pirimiphos-methyl. The KDT50 for 0.1% bendiocarb ranged from 2.8 to 62.9 minutes, whereas the KDT95 ranged from 36.0 to 88.5 minutes. Conclusions These findings indicate that bendiocarb and pirimiphos-methyl are still effective against the major malaria vector, A. arabiensis in Nsinze sub-county, Namutumba district, Uganda and can be effectively used for IRS. The study has provided baseline information on the insecticide susceptibility status on malaria vectors in the study area. However, routine continuous monitoring program of insecticide susceptibility and malaria vector composition is required so as to guide future decisions on insecticide use for IRS intervention toward malaria elimination and to track future changes in vector population.
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Affiliation(s)
- Julius Iga
- Department of Biology, Faculty of Science, Gulu University, P.O. Box 166 Gulu, Uganda
| | - Stephen Ochaya
- Department of Immunology and Microbiology, Faculty of Medicine, Gulu University, P.O. Box 166 Gulu, Uganda
| | - Richard Echodu
- Department of Biology, Faculty of Science, Gulu University, P.O. Box 166 Gulu, Uganda
| | - Elizabeth A. Opiyo
- Department of Biology, Faculty of Science, Gulu University, P.O. Box 166 Gulu, Uganda
| | - Alex K. Musiime
- National Malaria Control Division, Ministry of Health, Uganda
| | | | - Geoffrey M. Malinga
- Department of Biology, Faculty of Science, Gulu University, P.O. Box 166 Gulu, Uganda
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Hilton ER, Rabeherisoa S, Ramandimbiarijaona H, Rajaratnam J, Belemvire A, Kapesa L, Zohdy S, Dentinger C, Gandaho T, Jacob D, Burnett S, Razafinjato C. Using routine health data to evaluate the impact of indoor residual spraying on malaria transmission in Madagascar. BMJ Glob Health 2023; 8:e010818. [PMID: 37463785 PMCID: PMC10357738 DOI: 10.1136/bmjgh-2022-010818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 06/17/2023] [Indexed: 07/20/2023] Open
Abstract
INTRODUCTION Indoor residual spraying (IRS) and insecticide-treated bed nets (ITNs) are cornerstone malaria prevention methods in Madagascar. This retrospective observational study uses routine data to evaluate the impacts of IRS overall, sustained IRS exposure over multiple years and level of spray coverage (structures sprayed/found) in nine districts where non-pyrethroid IRS was deployed to complement standard pyrethroid ITNs from 2017 to 2020. METHODS Multilevel negative-binomial generalised linear models were fit to estimate the effects of IRS exposure overall, consecutive years of IRS exposure and spray coverage level on monthly all-ages population-adjusted malaria cases confirmed by rapid diagnostic test at the health facility level. The study period extended from July 2016 to June 2021. Facilities with missing data and non-geolocated communes were excluded. Facilities in IRS districts were matched with control facilities by propensity score analysis. Models were controlled for ITN survivorship, mass drug administration coverage, precipitation, enhanced vegetation index, seasonal effects and district. Predicted cases under a counterfactual no IRS scenario and number of cases averted by IRS were estimated using the fitted models. RESULTS Exposure to IRS overall reduced case incidence by an estimated 30.3% from 165.8 cases per 1000 population (95% CI=139.7 to 196.7) under a counterfactual no IRS scenario, to 114.3 (95% CI=96.5 to 135.3) over 12 months post-IRS campaign in nine districts. A third year of IRS reduced malaria cases 30.9% more than a first year (incidence rate ratio (IRR)=0.578, 95% CI=0.578 to 0.825, p<0.001) and 26.7% more than a second year (IRR=0.733, 95% CI=0.611 to 0.878, p=0.001). There was no significant difference between the first and second year (p>0.05). Coverage of 86%-90% was associated with a 19.7% reduction in incidence (IRR=0.803, 95% CI=0.690 to 0.934, p=0.005) compared with coverage ≤85%, although these results were not robust to sensitivity analysis. CONCLUSION This study demonstrates that non-pyrethroid IRS appears to substantially reduce malaria incidence in Madagascar and that sustained implementation of IRS over three years confers additional benefits.
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Affiliation(s)
| | - Saraha Rabeherisoa
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé Publique, Antananarivo, Madagascar
| | - Herizo Ramandimbiarijaona
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé Publique, Antananarivo, Madagascar
| | - Julie Rajaratnam
- Center for Digital and Data Excellence, PATH, Seattle, Washington, USA
| | - Allison Belemvire
- US Agency for International Development, US President's Malaria Initiative, Washington, District of Columbia, USA
| | - Laurent Kapesa
- US Agency for International Development, US President's Malaria Initiative, Antananarivo, Madagascar
| | - Sarah Zohdy
- Entomology Branch, US Centers for Disease Control and Prevention, US President's Malaria Initiative, Atlanta, Georgia, USA
| | - Catherine Dentinger
- Entomology Branch, US Centers for Disease Control and Prevention, US President's Malaria Initiative, Atlanta, Georgia, USA
| | - Timothee Gandaho
- PMI VectorLink Project, Abt Associates, Rockville, Maryland, USA
| | - Djenam Jacob
- PMI VectorLink Project, Abt Associates, Rockville, Maryland, USA
| | - Sarah Burnett
- PMI VectorLink Project, PATH, Washington, District of Columbia, USA
| | - Celestin Razafinjato
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé Publique, Antananarivo, Madagascar
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Wu SL, Henry JM, Citron DT, Mbabazi Ssebuliba D, Nakakawa Nsumba J, Sánchez C HM, Brady OJ, Guerra CA, García GA, Carter AR, Ferguson HM, Afolabi BE, Hay SI, Reiner RC, Kiware S, Smith DL. Spatial dynamics of malaria transmission. PLoS Comput Biol 2023; 19:e1010684. [PMID: 37307282 DOI: 10.1371/journal.pcbi.1010684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/15/2023] [Indexed: 06/14/2023] Open
Abstract
The Ross-Macdonald model has exerted enormous influence over the study of malaria transmission dynamics and control, but it lacked features to describe parasite dispersal, travel, and other important aspects of heterogeneous transmission. Here, we present a patch-based differential equation modeling framework that extends the Ross-Macdonald model with sufficient skill and complexity to support planning, monitoring and evaluation for Plasmodium falciparum malaria control. We designed a generic interface for building structured, spatial models of malaria transmission based on a new algorithm for mosquito blood feeding. We developed new algorithms to simulate adult mosquito demography, dispersal, and egg laying in response to resource availability. The core dynamical components describing mosquito ecology and malaria transmission were decomposed, redesigned and reassembled into a modular framework. Structural elements in the framework-human population strata, patches, and aquatic habitats-interact through a flexible design that facilitates construction of ensembles of models with scalable complexity to support robust analytics for malaria policy and adaptive malaria control. We propose updated definitions for the human biting rate and entomological inoculation rates. We present new formulas to describe parasite dispersal and spatial dynamics under steady state conditions, including the human biting rates, parasite dispersal, the "vectorial capacity matrix," a human transmitting capacity distribution matrix, and threshold conditions. An [Formula: see text] package that implements the framework, solves the differential equations, and computes spatial metrics for models developed in this framework has been developed. Development of the model and metrics have focused on malaria, but since the framework is modular, the same ideas and software can be applied to other mosquito-borne pathogen systems.
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Affiliation(s)
- Sean L Wu
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America
| | - John M Henry
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America
- Quantitative Ecology and Resource Management, University of Washington, Seattle, Washington, United States of America
| | - Daniel T Citron
- Department of Population Health, Grossman School of Medicine, New York University, New York, New York, United States of America
| | | | - Juliet Nakakawa Nsumba
- Department of Mathematics, Makerere University Department of Mathematics, School of Physical Sciences, College of Natural Science, Makerere University, Kampala, Uganda
| | - Héctor M Sánchez C
- Division of Epidemiology, School of Public Health, University of California Berkeley, Berkeley, California, United States of America
- Division of Biostatistics, School of Public Health, University of California Berkeley, Berkeley, California, United States of America
| | - Oliver J Brady
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Carlos A Guerra
- MCD Global Health, Silver Spring, Maryland, United States of America
| | | | - Austin R Carter
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America
| | - Heather M Ferguson
- Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Bakare Emmanuel Afolabi
- International Centre for Applied Mathematical Modelling and Data Analytics, Federal University Oye Ekiti, Ekiti State, Nigeria
- Department of Mathematics, Federal University Oye Ekiti, Ekiti State, Nigeria
| | - Simon I Hay
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America
- Department of Health Metrics Science, University of Washington, Seattle, Washington, United States of America
| | - Robert C Reiner
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America
- Department of Health Metrics Science, University of Washington, Seattle, Washington, United States of America
| | - Samson Kiware
- Ifakara Health Institute, Dar es Salaam, Tanzania
- Pan-African Mosquito Control Association (PAMCA), Nairobi, Kenya
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America
- Department of Health Metrics Science, University of Washington, Seattle, Washington, United States of America
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