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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [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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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 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Pambit Zong CM, Coleman S, Mohammed AR, Owusu-Asenso CM, Akuamoah-Boateng Y, Sraku IK, Attah SK, Cui L, Afrane YA. Baseline susceptibility of Anopheles gambiae to clothianidin in northern Ghana. Malar J 2024; 23:12. [PMID: 38195484 PMCID: PMC10777513 DOI: 10.1186/s12936-023-04769-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 10/25/2023] [Indexed: 01/11/2024] Open
Abstract
BACKGROUND Clothianidin, an insecticide with a novel mode of action, has been deployed in the annual indoor residual spraying programme in northern Ghana since March 2021. To inform pragmatic management strategies and guide future studies, baseline data on local Anopheles gambiae sensu lato (s.l.) susceptibility to the clothianidin insecticide were collected in Kpalsogu, a village in the Northern region, Ghana. METHODS Phenotypic susceptibility of An. gambiae mosquitoes to clothianidin was assessed using the World Health Organization (WHO) insecticide resistance monitoring bioassay. The WHO cone bioassays were conducted on mud and cement walls sprayed with Sumishield 50 wettable granules (WG) (with clothianidin active ingredient). Daily mortalities were recorded for up to 7 days to observe for delayed mortalities. Polymerase chain reaction (PCR) technique was used to differentiate the sibling species of the An. gambiae complex and also for the detection of knock down resistance genes (kdr) and the insensitive acetylcholinesterase mutation (ace-1). RESULTS The WHO susceptibility bioassay revealed a delayed killing effect of clothianidin. Mosquitoes exposed to the cone bioassays for 5 min died 120 h after exposure. Slightly higher mortalities were observed in mosquitoes exposed to clothianidin-treated cement wall surfaces than mosquitoes exposed to mud wall surfaces. The kdr target-site mutation L1014F occurred at very high frequencies (0.89-0.94) across all vector species identified whereas the ace-1 mutation occurred at moderate levels (0.32-0.44). Anopheles gambiae sensu stricto was the most abundant species observed at 63%, whereas Anopheles arabiensis was the least observed at 9%. CONCLUSIONS Anopheles gambiae s.l. mosquitoes in northern Ghana were susceptible to clothianidin. They harboured kdr mutations at high frequencies. The ace-1 mutation occurred in moderation. The results of this study confirm that clothianidin is an effective active ingredient and should be utilized in malaria vector control interventions.
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Affiliation(s)
- Cosmos M Pambit Zong
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Sylvester Coleman
- Department of Clinical Microbiology, Department of Clinical Microbiology, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Abdul Rahim Mohammed
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Christopher M Owusu-Asenso
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Yaw Akuamoah-Boateng
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Isaac K Sraku
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Simon K Attah
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Liwang Cui
- Department of Internal Medicine, University of South Florida, 3720 Spectrum Blvd, Tampa, FL, 33612, USA
| | - Yaw A Afrane
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana.
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Yewhalaw D, Simma EA, Zemene E, Zeleke K, Degefa T. Residual efficacy of SumiShield™ 50WG for indoor residual spraying in Ethiopia. Malar J 2022; 21:364. [PMID: 36461066 PMCID: PMC9716761 DOI: 10.1186/s12936-022-04395-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/19/2022] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The rate of decay of the biological efficacy of insecticides used for indoor residual spraying (IRS) is an important factor when making decisions on insecticide choice for national malaria control programmes. A key roadblock to IRS programme is insecticide resistance. If resistance is detected to most of the existing insecticides used for IRS (DDT, pyrethroids, organophosphates and carbamates), the logical next choice could be neonicotinoid insecticides, as pyrethroids are used to treat nets. SumiShield™ 50WG belongs to the neonicotinoid class of insecticides and has shown promising results in several phase I, II and III trials in different settings. The aim of this study was to assess the persistence of SumiShield™ 50WG by spraying on different wall surfaces and determine its decay rates over time in Ethiopia. METHODS Five huts with different wall surface types (mud, dung, paint and cement) which represented the Ethiopian house wall surfaces were used to evaluate the residual efficacy of SumiShield™ 50WG. Actellic 300CS sprayed on similar wall surfaces of another five huts was used as a comparator insecticide and two huts sprayed with water were used as a control. All huts were sprayed uniformly by an experienced spray operator; non-stop starting from the door and moving clockwise to cover the entire wall surface of the hut. The treatments were assigned to huts randomly. The residual efficacy of the insecticide formulations was evaluated against a susceptible insectary-reared population of Anopheles arabiensis using WHO cone bioassays. RESULTS SumiShield™ 50WG resulted in mortality rates of over 80% at 120 h post-exposure on all surface types for up to nine months post-spray, while Actellic 300CS yielded mortality rates of over 80% for eight months after spray. CONCLUSIONS The results of this trial demonstrated that the residual efficacy of SumiShield™ 50WG extends up to nine months on all treated wall surface types. The long-lasting residual efficacy and unique mode of action of the SemiShield™ 50WG shows that it could be an ideal product to be considered as a potential candidate insecticide formulation for IRS in malaria endemic countries such as Ethiopia or other sub-Saharan countries where the transmission season lasts up to four months or longer.
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Affiliation(s)
- Delenasaw Yewhalaw
- grid.411903.e0000 0001 2034 9160School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia ,grid.411903.e0000 0001 2034 9160Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Eba Alemayehu Simma
- grid.411903.e0000 0001 2034 9160Departement of Biology, College of Natural Sciences, Jimma University, Jimma, Ethiopia
| | - Endalew Zemene
- grid.411903.e0000 0001 2034 9160School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Kassahun Zeleke
- grid.411903.e0000 0001 2034 9160Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Teshome Degefa
- grid.411903.e0000 0001 2034 9160School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
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Fernández Montoya L, Máquina M, Martí-Soler H, Sherrard-Smith E, Alafo C, Opiyo M, Comiche K, Galatas B, Huijben S, Koekemoer LL, Oliver SV, Maartens F, Marrenjo D, Cuamba N, Aide P, Saúte F, Paaijmans KP. The realized efficacy of indoor residual spraying campaigns falls quickly below the recommended WHO threshold when coverage, pace of spraying and residual efficacy on different wall types are considered. PLoS One 2022; 17:e0272655. [PMID: 36190958 PMCID: PMC9529131 DOI: 10.1371/journal.pone.0272655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 07/22/2022] [Indexed: 11/06/2022] Open
Abstract
Indoor residual spraying (IRS) has been and remains an important malaria control intervention in southern Mozambique, South Africa and Eswatini. A better understanding of the effectiveness of IRS campaigns is critical to guide future elimination efforts. We analyze the three IRS campaigns conducted during a malaria elimination demonstration project in southern Mozambique, the "Magude project", and propose a new method to calculate the efficacy of IRS campaigns adjusting for IRS coverage, pace of house spraying and IRS residual efficacy on different wall types. Anopheles funestus sensu lato (s.l.) and An. gambiae s.l. were susceptible to pirimiphos-methyl and DDT. Anopheles funestus s.l. was resistant to pyrethroids, with 24h post-exposure mortality being lower for An. funestus sensu stricto (s.s.) than for An. parensis (collected indoors). The percentage of structures sprayed was above 90% and percentage of people covered above 86% in all three IRS campaigns. The percentage of households sprayed was above 83% in 2015 and 2016, but not assessed in 2017. Mosquito mortality 24h post-exposure stayed above 80% for 196 days after the 2016 IRS campaign and 222 days after the 2017 campaign and was 1.5 months longer on mud walls than on cement walls. This was extended by up to two months when 120h post-exposure mortality was considered. The district-level realized IRS efficacy was 113 days after the 2016 campaign. While the coverage of IRS campaigns in Magude were high, IRS protection did not remain optimal for the entire high malaria transmissions season. The use of a longer-lasting IRS product could have further supported the interruption of malaria transmission in the district. To better estimate the protection afforded by IRS campaigns, National Malaria Control Programs and partners are encouraged to adjust the calculation of IRS efficacy for IRS coverage, pace of house spraying during the campaign and IRS efficacy on different wall types combined with wall type distribution in the sprayed area.
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Affiliation(s)
- Lucia Fernández Montoya
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
- ISGlobal, Barcelona, Spain
| | - Mara Máquina
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
| | | | - Ellie Sherrard-Smith
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
| | - Celso Alafo
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
| | - Mercy Opiyo
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
- ISGlobal, Barcelona, Spain
| | - Kiba Comiche
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
| | - Beatriz Galatas
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
- ISGlobal, Barcelona, Spain
| | - Silvie Huijben
- ISGlobal, Barcelona, Spain
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Simon A. Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, Arizona, United States of America
| | - Lizette L. Koekemoer
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, Johannesburg, South Africa
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - Shüné V. Oliver
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, Johannesburg, South Africa
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | | | | | - Nelson Cuamba
- National Malaria Control Programme, Ministry of Health, Maputo, Mozambique
- PMI VectorLink Project, Abt Associates Inc., Maputo, Mozambique
| | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Francisco Saúte
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
| | - Krijn P. Paaijmans
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
- ISGlobal, Barcelona, Spain
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Simon A. Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, AZ, United States of America
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6
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Mbwambo SG, Bubun N, Mbuba E, Moore J, Mbina K, Kamande D, Laman M, Mpolya E, Odufuwa OG, Freeman T, Karl S, Moore SJ. Comparison of cone bioassay estimates at two laboratories with different Anopheles mosquitoes for quality assurance of pyrethroid insecticide-treated nets. Malar J 2022; 21:214. [PMID: 35799172 PMCID: PMC9264565 DOI: 10.1186/s12936-022-04217-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 06/11/2022] [Indexed: 11/16/2022] Open
Abstract
Background Quality assurance (QA) of insecticide-treated nets (ITNs) delivered to malaria-endemic countries is conducted by measuring physiochemical parameters, but not bioefficacy against malaria mosquitoes. This study explored utility of cone bioassays for pre-delivery QA of pyrethroid ITNs to test the assumption that cone bioassays are consistent across locations, mosquito strains, and laboratories. Methods Double-blinded bioassays were conducted on twenty unused pyrethroid ITNs of 4 brands (100 nets, 5 subsamples per net) that had been delivered for mass distribution in Papua New Guinea (PNG) having passed predelivery inspections. Cone bioassays were performed on the same net pieces following World Health Organization (WHO) guidelines at the PNG Institute of Medical Research (PNGIMR) using pyrethroid susceptible Anopheles farauti sensu stricto (s.s.) and at Ifakara Health Institute (IHI), Tanzania using pyrethroid susceptible Anopheles gambiae s.s. Additionally, WHO tunnel tests were conducted at IHI on ITNs that did not meet cone bioefficacy thresholds. Results from IHI and PNGIMR were compared using Spearman’s Rank correlation, Bland–Altman (BA) analysis and analysis of agreement. Literature review on the use of cone bioassays for unused pyrethroid ITNs testing was conducted. Results In cone bioassays, 13/20 nets (65%) at IHI and 8/20 (40%) at PNGIMR met WHO bioefficacy criteria. All nets met WHO bioefficacy criteria on combined cone/tunnel tests at IHI. Results from IHI and PNGIMR correlated on 60-min knockdown (KD60) (rs = 0.6,p = 0.002,n = 20) and 24-h mortality (M24) (rs = 0.9,p < 0.0001,n = 20) but BA showed systematic bias between the results. Of the 5 nets with discrepant result between IHI and PNGIMR, three had confidence intervals overlapping the 80% mortality threshold, with averages within 1–3% of the threshold. Including these as a pass, the agreement between the results to predict ITN failure was good with kappa = 0.79 (0.53–1.00) and 90% accuracy. Conclusions Based on these study findings, the WHO cone bioassay is a reproducible bioassay for ITNs with > 80% M24, and for all ITNs provided inherent stochastic variation and systematic bias are accounted for. The literature review confirms that WHO cone bioassay bioefficacy criteria have been previously achieved by all pyrethroid ITNs (unwashed), without the need for additional tunnel tests. The 80% M24 threshold remains the most reliable indicator of pyrethroid ITN quality using pyrethroid susceptible mosquitoes. In the absence of alternative tests, cone bioassays could be used as part of pre-delivery QA.
Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04217-3.
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Affiliation(s)
- Stephen G Mbwambo
- Vector Control Product Testing Unit (VCPTU), Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania. .,Nelson Mandela Africa Institution of Science and Technology, Arusha, Tanzania. .,Sokoine RRH, Ministry of Health, Lindi, Tanzania. .,Regional Health Management Team, P.O Box 1011, Lindi, Tanzania.
| | - Nakei Bubun
- Vector Borne Disease Unit, PNG Institute of Medical Research, Madang Province 511, P.O Box 378, Madang, Papua New Guinea
| | - Emmanuel Mbuba
- Vector Control Product Testing Unit (VCPTU), Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania.,University of Basel, Basel, Switzerland.,Vector Biology Unit, Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute (Swiss TPH, Allschwil, Kreuzstrasse 2, 4123, , Basel, Switzerland
| | - Jason Moore
- Vector Control Product Testing Unit (VCPTU), Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania.,Vector Biology Unit, Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute (Swiss TPH, Allschwil, Kreuzstrasse 2, 4123, , Basel, Switzerland
| | - Kasiani Mbina
- Vector Control Product Testing Unit (VCPTU), Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Dismas Kamande
- Vector Control Product Testing Unit (VCPTU), Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania.,Nelson Mandela Africa Institution of Science and Technology, Arusha, Tanzania
| | - Moses Laman
- Vector Borne Disease Unit, PNG Institute of Medical Research, Madang Province 511, P.O Box 378, Madang, Papua New Guinea
| | - Emmanuel Mpolya
- Nelson Mandela Africa Institution of Science and Technology, Arusha, Tanzania
| | - Olukayode G Odufuwa
- Vector Control Product Testing Unit (VCPTU), Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania.,University of Basel, Basel, Switzerland.,Vector Biology Unit, Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute (Swiss TPH, Allschwil, Kreuzstrasse 2, 4123, , Basel, Switzerland.,MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Tim Freeman
- Rotarian Against Malaria, P.O Box 3686, Boroko, NCD 111, Papua New Guinea
| | - Stephan Karl
- Vector Borne Disease Unit, PNG Institute of Medical Research, Madang Province 511, P.O Box 378, Madang, Papua New Guinea.,Australian Institute of Tropical Health and Medicine, James Cook University, 1/14-88 McGregor Road, Smithfield, QLD, 4870, Australia
| | - Sarah J Moore
- Vector Control Product Testing Unit (VCPTU), Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania.,Nelson Mandela Africa Institution of Science and Technology, Arusha, Tanzania.,University of Basel, Basel, Switzerland.,Vector Biology Unit, Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute (Swiss TPH, Allschwil, Kreuzstrasse 2, 4123, , Basel, Switzerland
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7
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Lees RS, Praulins G, Lissenden N, South A, Carson J, Brown F, Lucas J, Malone D. The Residual Efficacy of SumiShield™ 50WG and K-Othrine® WG250 IRS Formulations Applied to Different Building Materials against Anopheles and Aedes Mosquitoes. Insects 2022; 13:insects13020112. [PMID: 35206686 PMCID: PMC8877416 DOI: 10.3390/insects13020112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/07/2022] [Accepted: 01/09/2022] [Indexed: 12/04/2022]
Abstract
Insecticides with novel modes of action are required to complement the pyrethroids currently relied upon for controlling malaria vectors. One example of this is the neonicotinoid clothianidin, the active ingredient in the indoor residual spray (IRS) SumiShield™ 50WG. In a preliminary experiment, the mortality of insecticide-susceptible and resistant An. gambiae adults exposed to filter papers treated with this IRS product reached 80% by 3 days post-exposure and 100% by 6 days post-exposure. Next, cement, wood, and mud tiles were treated with the clothianidin or a deltamethrin-based IRS formulation (K-Othrine WG250). Insecticide resistant and susceptible Anopheles and Aedes were exposed to these surfaces periodically for up to 18 months. Pyrethroid resistant Cx. quinquefasciatus was also exposed at 9 months. Between exposures, tiles were stored in heat and relative humidity conditions reflecting those found in the field. On these surfaces, the clothianidin IRS was effective at killing both susceptible and resistant An. gambiae for 18 months post-treatment, while mortality amongst the resistant strains when exposed to the deltamethrin IRS was not above that of the negative control. Greater efficacy of clothianidin was also demonstrated against insecticide resistant strains of An. funestus compared to deltamethrin, though the potency was lower when compared with An. gambiae. In general, higher efficacy of the clothianidin IRS was observed on cement and mud compared to wood, though it demonstrated poorer residual activity against Ae.aegypti and Cx. quinquefasciatus.
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Affiliation(s)
- Rosemary Susan Lees
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (G.P.); (N.L.); (A.S.); (J.C.); (F.B.)
- Liverpool Insect Testing Establishment (LITE), Liverpool School of Tropical Medicine, 1 Daulby Street, Liverpool L7 8XZ, UK
- Correspondence: ; Tel.: +44-(0)-151-705-3344
| | - Giorgio Praulins
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (G.P.); (N.L.); (A.S.); (J.C.); (F.B.)
| | - Natalie Lissenden
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (G.P.); (N.L.); (A.S.); (J.C.); (F.B.)
| | - Andy South
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (G.P.); (N.L.); (A.S.); (J.C.); (F.B.)
| | - Jessica Carson
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (G.P.); (N.L.); (A.S.); (J.C.); (F.B.)
- Liverpool Insect Testing Establishment (LITE), Liverpool School of Tropical Medicine, 1 Daulby Street, Liverpool L7 8XZ, UK
| | - Faye Brown
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (G.P.); (N.L.); (A.S.); (J.C.); (F.B.)
- Institute of Infection, Veterinary and Ecological Sciences, Department of Livestock and One Health, The University of Liverpool, Liverpool L69 3BX, UK
| | - John Lucas
- Environmental Health Division, Sumitomo Chemical (UK) plc, 200 Shepherds Bush Rd, London W6 7NL, UK;
| | - David Malone
- Innovative Vector Control Consortium (IVCC), Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK;
- Bill & Melinda Gates Foundation, 500 5th Ave N, Seattle, WA 98109, USA
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8
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Epstein A, Maiteki-Sebuguzi C, Namuganga JF, Nankabirwa JI, Gonahasa S, Opigo J, Staedke SG, Rutazaana D, Arinaitwe E, Kamya MR, Bhatt S, Rodríguez-Barraquer I, Greenhouse B, Donnelly MJ, Dorsey G. Resurgence of malaria in Uganda despite sustained indoor residual spraying and repeated long lasting insecticidal net distributions. PLOS Glob Public Health 2022; 2:e0000676. [PMID: 36962736 PMCID: PMC10022262 DOI: 10.1371/journal.pgph.0000676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 07/27/2022] [Indexed: 11/19/2022]
Abstract
Five years of sustained indoor residual spraying (IRS) of insecticide from 2014 to 2019, first using a carbamate followed by an organophosphate, was associated with a marked reduction in the incidence of malaria in five districts of Uganda. We assessed changes in malaria incidence over an additional 21 months, corresponding to a change in IRS formulations using clothianidin with and without deltamethrin. Using enhanced health facility surveillance data, our objectives were to 1) estimate the impact of IRS on monthly malaria case counts at five surveillance sites over a 6.75 year period, and 2) compare monthly case counts at five facilities receiving IRS to ten facilities in neighboring districts not receiving IRS. For both objectives, we specified mixed effects negative binomial regression models with random intercepts for surveillance site adjusting for rainfall, season, care-seeking, and malaria diagnostic. Following the implementation of IRS, cases were 84% lower in years 4-5 (adjusted incidence rate ratio [aIRR] = 0.16, 95% CI 0.12-0.22), 43% lower in year 6 (aIRR = 0.57, 95% CI 0.44-0.74), and 39% higher in the first 9 months of year 7 (aIRR = 1.39, 95% CI 0.97-1.97) compared to pre-IRS levels. Cases were 67% lower in IRS sites than non-IRS sites in year 6 (aIRR = 0.33, 95% CI 0.17-0.63) but 38% higher in the first 9 months of year 7 (aIRR = 1.38, 95% CI 0.90-2.11). We observed a resurgence in malaria to pre-IRS levels despite sustained IRS. The timing of this resurgence corresponded to a change of active ingredient. Further research is needed to determine causality.
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Affiliation(s)
- Adrienne Epstein
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, United States of America
| | | | | | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- College of Health Sciences, Makerere University, Kampala, Uganda
| | | | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Sarah G Staedke
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Damian Rutazaana
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | | | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Samir Bhatt
- Department of Infectious Disease Epidemiology, Imperial College, St Mary's Hospital, London, United Kingdom
- Department of Public Health, Section of Epidemiology, University of Copenhagen, Copenhagen, Denmark
| | - Isabel Rodríguez-Barraquer
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
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