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Nikpour F, Vatandoost H, Hanafi-Bojd AA, Raeisi A, Mirolyaie A, Mojahedi AR, Yaryan M, Banar A, Kaveh F, Abbasi M, Farmani M. Long-lasting residual efficacy of Actellic®300CS and Icon®10CS on different surfaces against Anopheles stephensi, an invasive malaria vector. Trop Med Int Health 2024; 29:781-791. [PMID: 39081142 DOI: 10.1111/tmi.14028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/03/2024]
Abstract
BACKGROUND Anopheles stephensi, a malaria-transmitting mosquito species, has developed resistance to various insecticides such as DDT, Dieldrin, Malathion, and synthetic pyrethroids. To combat this issue, the World Health Organization (WHO) suggests using Actellic®300CS and Icon®10CS for Indoor Residual Spraying to tackle pyrethroid-resistant mosquitoes. The aim of this research project was to evaluate the susceptibility of An. stephensi to certain insecticides at the diagnostic concentration + intensity 5x diagnostic concentration (5XDC) assays in Iran and to study the lasting effectiveness of Actellic®300CS and Icon®10CS against this particular malaria vector. METHODS This study assessed the susceptibility of An. stephensi populations in southern Iran to various insecticides, including deltamethrin 0.05%, DDT 4%, malathion 5%, bendiocarb 0.1%, a synergist assay with PBO 4% combined with deltamethrin 0.05%, and an intensity assay using 5x the diagnostic concentration of deltamethrin (0.25%) and bendiocarb 0.5%. Laboratory cone bioassay tests were conducted to determine the residual effectiveness of Actellic®300 and Icon®10CS insecticides on different surfaces commonly found in households, such as cement, mud, plaster, and wood. The tests were carried out following the WHO test kits and standard testing protocols. RESULTS The An. stephensi populations in Bandar Abbas were found to be susceptible to malathion 5% and deltamethrin 0.25% (5XDC), but exhibited resistance to DDT, standard concentration of deltamethrin, and both standard and intensity concentrations of bendiocarb. In laboratory cone bioassay tests, An. stephensi mortality rates when exposed to Actellic®300CS and Icon®10CS on different surfaces remained consistently more than 80%. Actellic®300CS achieved more than 80% mortality on all substrates for the entire 300-day post-spraying period. Conversely, Icon®10CS maintained mortality rates more than 80% on plaster and wood surfaces for 165 days and on mud and cement surfaces for 270 days post-spraying. Both Actellic®300CS and Icon®10CS demonstrated 100% mortality within 72 h of each test on all surfaces throughout the entire 300-day post-spraying period. CONCLUSION The study shows the varying levels of resistance of An. stephensi Bandar Abbas population to different insecticides and demonstrates the consistent performance of Actellic®300CS in controlling these mosquitoes on various surfaces. The findings suggest that long-lasting CS formulations may be more effective for malaria vector control compared to the current options. Further research is needed to validate these findings in field settings and assess the impact of these insecticides on malaria transmission.
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Affiliation(s)
- Fatemeh Nikpour
- Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran
- Department of Vector-Borne Diseases, Centre for Communicable Diseases Control, Ministry of Health, Tehran, Iran
| | - Hassan Vatandoost
- Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran
- Department of Vector Biology & Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Ali Hanafi-Bojd
- Department of Vector Biology & Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Raeisi
- Department of Vector-Borne Diseases, Centre for Communicable Diseases Control, Ministry of Health, Tehran, Iran
- Department of Vector Biology & Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Abdolreza Mirolyaie
- Department of Vector-Borne Diseases, Centre for Communicable Diseases Control, Ministry of Health, Tehran, Iran
| | | | - Masoud Yaryan
- Deputy of Health, Hormozgan University of Medical Sciences, Tehran, Iran
| | - Ahad Banar
- Department of Medical Parasitology & Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Farzad Kaveh
- Department of Vector-Borne Diseases, Centre for Communicable Diseases Control, Ministry of Health, Tehran, Iran
| | - Madineh Abbasi
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mostafa Farmani
- Department of Parasitology and Mycology at the Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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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. PLOS GLOBAL PUBLIC HEALTH 2024; 4:e0003254. [PMID: 39208072 PMCID: PMC11361418 DOI: 10.1371/journal.pgph.0003254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 06/07/2024] [Indexed: 09/04/2024]
Abstract
Tororo District, Uganda experienced a dramatic decrease in malaria burden from 2015-19 during 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. 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. 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. 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, Kampala, Uganda
| | - Joaniter I. Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- School of Medicine, Makerere University Kampala, 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, United States of America
| | - Jessica Briggs
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Paul J. Krezanoski
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Philip J. Rosenthal
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Peter Olwoch
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Prasanna Jagannathan
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, California, United States of America
| | - Isabel Rodriguez-Barraquer
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
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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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Hamid-Adiamoh M, Muhammad AK, Assogba BS, Soumare HM, Jadama L, Diallo M, D'Alessandro U, Ousmane Ndiath M, Erhart A, Amambua-Ngwa A. Mosquitocidal effect of ivermectin-treated nettings and sprayed walls on Anopheles gambiae s.s. Sci Rep 2024; 14:12620. [PMID: 38824239 PMCID: PMC11144240 DOI: 10.1038/s41598-024-63389-x] [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: 06/01/2023] [Accepted: 05/28/2024] [Indexed: 06/03/2024] Open
Abstract
Ivermectin (IVM) has been proposed as a new tool for malaria control as it is toxic on vectors feeding on treated humans or cattle. Nevertheless, IVM may have a direct mosquitocidal effect when applied on bed nets or sprayed walls. The potential for IVM application as a new insecticide for long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) was tested in this proof-of-concept study in a laboratory and semi-field environment. Laboratory-reared, insecticide-susceptible Kisumu Anopheles gambiae were exposed to IVM on impregnated netting materials and sprayed plastered- and mud walls using cone bioassays. The results showed a direct mosquitocidal effect of IVM on this mosquito strain as all mosquitoes died by 24 h after exposure to IVM. The effect was slower on the IVM-sprayed walls compared to the treated nettings. Further work to evaluate possibility of IVM as a new insecticide formulation in LLINs and IRS will be required.
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Affiliation(s)
- Majidah Hamid-Adiamoh
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia.
| | - Abdul Khalie Muhammad
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Benoit Sessinou Assogba
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Harouna Massire Soumare
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Lamin Jadama
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Moussa Diallo
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Mamadou Ousmane Ndiath
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Annette Erhart
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
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Ekra AK, Edi CAV, Gbalegba GCN, Zahouli JZB, Danho M, Koudou BG. Can neonicotinoid and pyrrole insecticides manage malaria vector resistance in high pyrethroid resistance areas in Côte d'Ivoire? Malar J 2024; 23:160. [PMID: 38778399 PMCID: PMC11112771 DOI: 10.1186/s12936-024-04917-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 03/23/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Anopheles mosquito resistance to insecticide remains a serious threat to malaria vector control affecting several sub-Sahara African countries, including Côte d'Ivoire, where high pyrethroid, carbamate and organophosphate resistance have been reported. Since 2017, new insecticides, namely neonicotinoids (e.g.; clothianidin) and pyrroles (e.g.; chlorfenapyr) have been pre-qualified by the World Health Organization (WHO) for use in public health to manage insecticide resistance for disease vector control. METHODS Clothianidin and chlorfenapyr were tested against the field-collected Anopheles gambiae populations from Gagnoa, Daloa and Abengourou using the WHO standard insecticide susceptibility biossays. Anopheles gambiae larvae were collected from several larval habitats, pooled and reared to adulthood in each site in July 2020. Non-blood-fed adult female mosquitoes aged 2 to 5 days were exposed to diagnostic concentration deltamethrin, permethrin, alpha-cypermethrin, bendiocarb, and pirimiphos-methyl. Clothianidin 2% treated papers were locally made and tested using WHO tube bioassay while chlorfenapyr (100 µg/bottle) was evaluated using WHO bottle assays. Furthermore, subsamples of exposed mosquitoes were identified to species and genotyped for insecticide resistance markers including the knock-down resistance (kdr) west and east, and acetylcholinesterase (Ace-1) using molecular techniques. RESULTS High pyrethroid resistance was recorded with diagnostic dose in Abengourou (1.1 to 3.4% mortality), in Daloa (15.5 to 33.8%) and in Gagnoa (10.3 to 41.6%). With bendiocarb, mortality rates ranged from 49.5 to 62.3%. Complete mortality (100% mortality) was recorded with clothianidin in Gagnoa, 94.9% in Daloa and 96.6% in Abengourou, while susceptibility (mortality > 98%) to chlorfenapyr 100 µg/bottle was recorded at all sites and to pirimiphos-methyl in Gagnoa and Abengourou. Kdr-west mutation was present at high frequency (0.58 to 0.73) in the three sites and Kdr-east mutation frequency was recorded at a very low frequency of 0.02 in both Abengourou and Daloa samples and absent in Gagnoa. The Ace-1 mutation was present at frequencies between 0.19 and 0.29 in these areas. Anopheles coluzzii represented 100% of mosquitoes collected in Daloa and Gagnoa, and 72% in Abengourou. CONCLUSIONS This study showed that clothianidin and chlorfenapyr insecticides induce high mortality in the natural and pyrethroid-resistant An. gambiae populations in Côte d'Ivoire. These results could support a resistance management plan by proposing an insecticide rotation strategy for vector control interventions.
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Affiliation(s)
- Armand K Ekra
- UMRI 28, Sciences Agronomiques et Procédés de Transformation, Laboratoire de Zoologie Agricole et Entomologie, Institut National Polytechnique Félix Houphouët-Boigny (INP-HB), Yamoussoukro, République de Côte d'Ivoire.
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, République de Côte d'Ivoire.
| | - Constant A V Edi
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, République de Côte d'Ivoire
| | | | - Julien Z B Zahouli
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, République de Côte d'Ivoire
- Centre d'Entomologie Médicale et Vétérinaire, Université Alassane Ouattara, Bouaké, République de Côte d'Ivoire
| | - Mathias Danho
- UMRI 28, Sciences Agronomiques et Procédés de Transformation, Laboratoire de Zoologie Agricole et Entomologie, Institut National Polytechnique Félix Houphouët-Boigny (INP-HB), Yamoussoukro, République de Côte d'Ivoire
| | - Benjamin G Koudou
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, République de Côte d'Ivoire
- Laboratoire d'Entomologie, UFR Sciences de la Nature, Université Nangui Abrogoua, Abidjan, République de Côte d'Ivoire
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Fodjo BK, Tchicaya E, Yao LA, Edi C, Ouattara AF, Kouassi LB, Yokoly FN, Benjamin KG. Efficacy of Pirikool® 300 CS used for indoor residual spraying on three different substrates in semi-field experimental conditions. Malar J 2024; 23:148. [PMID: 38750468 PMCID: PMC11097411 DOI: 10.1186/s12936-024-04912-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 03/19/2024] [Indexed: 05/18/2024] Open
Abstract
BACKGROUND Vector control using insecticides is a key prevention strategy against malaria. Unfortunately, insecticide resistance in mosquitoes threatens all progress in malaria control. In the perspective of managing this resistance, new insecticide formulations are being tested to improve the effectiveness of vector control tools. METHODS The efficacy and residual activity of Pirikool® 300 CS was evaluated in comparison with Actellic® 300 CS in experimental huts at the Tiassalé experimental station on three substrates including cement, wood and mud. The mortality, blood-feeding inhibition, exiting behaviour and deterrency of free-flying wild mosquitoes was evaluated. Cone bioassay tests with susceptible and resistant mosquito strains were conducted in the huts to determine residual efficacy. RESULTS A total of 20,505 mosquitoes of which 10,979 (53%) wild female Anopheles gambiae were collected for 112 nights. Residual efficacy obtained from monthly cone bioassay was higher than 80% with the susceptible, laboratory-maintained An. gambiae Kisumu strain, from the first to the tenth study period on all three types of treated substrate for both Actellic® 300CS and Pirikool® 300CS. This residual efficacy on the wild Tiassalé strain was over 80% until the 4th month of study on Pirikool® 300CS S treated substrates. Overall 24-h mortalities of wild free-flying An. gambiae sensu lato which entered in the experimental huts over the 8-months trial on Pirikool® 300CS treatment was 50.5%, 75.9% and 52.7%, respectively, on cement wall, wood wall and mud wall. The positive reference product Actellic® 300CS treatment induced mortalities of 42.0%, 51.8% and 41.8% on cement wall, wood wall and mud wall. CONCLUSION Pirikool® 300CS has performed really well against resistant strains of An. gambiae using indoor residual spraying method in experimental huts. It could be an alternative product for indoor residual spraying in response to the vectors' resistance to insecticides.
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Affiliation(s)
- Behi Kouadio Fodjo
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire (CSRS), Abidjan, Côte d'Ivoire.
- Université Nangui Abrogoua, Abidjan, Côte d'Ivoire.
| | - Emile Tchicaya
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire (CSRS), Abidjan, Côte d'Ivoire
- Université Peleforo Gon Coulibaly (UPGC), Korhogo, Côte d'Ivoire
| | - Laurence Aya Yao
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire (CSRS), Abidjan, Côte d'Ivoire
| | - Constant Edi
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire (CSRS), Abidjan, Côte d'Ivoire
| | - Alassane Foungoye Ouattara
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire (CSRS), Abidjan, Côte d'Ivoire
- Université Nangui Abrogoua, Abidjan, Côte d'Ivoire
| | - Loukou Bernard Kouassi
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire (CSRS), Abidjan, Côte d'Ivoire
| | - Firmain N'dri Yokoly
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire (CSRS), Abidjan, Côte d'Ivoire
- Université Nangui Abrogoua, Abidjan, Côte d'Ivoire
| | - Koudou Guibéhi Benjamin
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire (CSRS), Abidjan, Côte d'Ivoire
- Université Nangui Abrogoua, Abidjan, Côte d'Ivoire
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7
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Odjo EM, Akpodji CST, Djènontin A, Salako AS, Padonou GG, Adoha CJ, Yovogan B, Adjottin B, Tokponnon FT, Osse R, Agbangla C, Akogbeto MC. Did the prolonged residual efficacy of clothianidin products lead to a greater reduction in vector populations and subsequent malaria transmission compared to the shorter residual efficacy of pirimiphos-methyl? Malar J 2024; 23:119. [PMID: 38664703 PMCID: PMC11047034 DOI: 10.1186/s12936-024-04949-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 04/13/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND The residual activity of a clothianidin + deltamethrin mixture and clothianidin alone in IRS covered more than the period of malaria transmission in northern Benin. The aim of this study was to show whether the prolonged residual efficacy of clothianidin-based products resulted in a greater reduction in vector populations and subsequent malaria transmission compared with the shorter residual efficacy of pirimiphos-methyl. METHODS Human bait mosquito collections by local volunteers and pyrethrum spray collections were used in 6 communes under IRS monitoring and evaluation from 2019 to 2021. ELISA/CSP and species PCR tests were performed on Anopheles gambiae sensu lato (s.l.) to determine the infectivity rate and subspecies by commune and year. The decrease in biting rate, entomological inoculation rate, incidence, inhibition of blood feeding, resting density of An. gambiae s.l. were studied and compared between insecticides per commune. RESULTS The An. gambiae complex was the major vector throughout the study area, acounting for 98.71% (19,660/19,917) of all Anopheles mosquitoes collected. Anopheles gambiae s.l. collected was lower inside treated houses (45.19%: 4,630/10,245) than outside (54.73%: 5,607/10,245) after IRS (p < 0.001). A significant decrease (p < 0.001) in the biting rate was observed after IRS in all departments except Donga in 2021 after IRS with clothianidin 50 WG. The impact of insecticides on EIR reduction was most noticeable with pirimiphos-methyl 300 CS, followed by the clothianidin + deltamethrin mixture and finally clothianidin 50 WG. A reduction in new cases of malaria was observed in 2020, the year of mass distribution of LLINs and IRS, as well as individual and collective protection measures linked to COVID-19. Anopheles gambiae s.l. blood-feeding rates and parous were high and similar for all insecticides in treated houses. CONCLUSION To achieve the goal of zero malaria, the optimal choice of vector control tools plays an important role. Compared with pirimiphos-methyl, clothianidin-based insecticides induced a lower reductions in entomological indicators of malaria transmission.
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Affiliation(s)
- Esdras Mahoutin Odjo
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin.
- Faculté des Sciences et Techniques, Université d'Abomey- Calavi, Calavi, Bénin.
| | - Christian S T Akpodji
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
- Faculté des Sciences et Techniques, Université d'Abomey- Calavi, Calavi, Bénin
| | - Armel Djènontin
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
- Faculté des Sciences et Techniques, Université d'Abomey- Calavi, Calavi, Bénin
| | | | - Gil Germain Padonou
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
- Faculté des Sciences et Techniques, Université d'Abomey- Calavi, Calavi, Bénin
| | - Constantin Jésukèdè Adoha
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
- Faculté des Sciences et Techniques, Université d'Abomey- Calavi, Calavi, Bénin
| | - Boulais Yovogan
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
- Faculté des Sciences et Techniques, Université d'Abomey- Calavi, Calavi, Bénin
| | - Bruno Adjottin
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
- Faculté des Sciences et Techniques, Université d'Abomey- Calavi, Calavi, Bénin
| | - Filémon T Tokponnon
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
- Faculté des Sciences et Techniques, Université d'Abomey- Calavi, Calavi, Bénin
| | - Razaki Osse
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
- Université Nationale d'Agriculture de Porto-Novo, Porto-Novo, Bénin
| | - Clement Agbangla
- Centre de Recherche Entomologique de Cotonou, Cotonou, Bénin
- Direction Générale de la Recherche Scientifique, Ministère de l'Enseignement Supérieur et de la Recherche Scientifique, Cotonou, Bénin
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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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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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Azizi S, Mbewe NJ, Mo H, Edward F, Sumari G, Mwacha S, Msapalla A, Mawa B, Mosha F, Matowo J. Is Anopheles gambiae ( sensu stricto), the principal malaria vector in Africa prone to resistance development against new insecticides? Outcomes from laboratory exposure of An. gambiae ( s.s.) to sub-lethal concentrations of chlorfenapyr and clothianidin. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2024; 5:100172. [PMID: 38444984 PMCID: PMC10912349 DOI: 10.1016/j.crpvbd.2024.100172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 12/05/2023] [Accepted: 02/17/2024] [Indexed: 03/07/2024]
Abstract
Indiscriminate use of pesticides in the public health and agriculture sectors has contributed to the development of resistance in malaria vectors following exposure to sub-lethal concentrations. To preserve the efficacy of vector control tools and prevent resistance from spreading, early resistance detection is urgently needed to inform management strategies. The introduction of new insecticides for controlling malaria vectors such as clothianidin and chlorfenapyr requires research to identify early markers of resistance which could be used in routine surveillance. This study investigated phenotypic resistance of Anopheles gambiae (sensu stricto) Muleba-Kis strain using both WHO bottle and tube assays following chlorfenapyr, clothianidin, and alpha-cypermethrin selection against larvae and adults under laboratory conditions. High mortality rates were recorded for both chlorfenapyr-selected mosquitoes that were consistently maintained for 10 generations (24-h mortality of 92-100% and 72-h mortality of 98-100% for selected larvae; and 24-h mortality of 95-100% and 72-h mortality of 98-100% for selected adults). Selection with clothianidin at larval and adult stages showed a wide range of mortality (18-91%) compared to unselected progeny where mortality was approximately 99%. On the contrary, mosquitoes selected with alpha-cypermethrin from the adult selection maintained low mortality (28% at Generation 2 and 23% at Generation 4) against discrimination concentration compared to unselected progeny where average mortality was 51%. The observed resistance in the clothianidin-selected mosquitoes needs further investigation to determine the underlying resistance mechanism against this insecticide class. Additionally, further investigation is recommended to develop molecular markers for observed clothianidin phenotypic resistance.
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Affiliation(s)
- Salum Azizi
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Tanzania
- Pan African Malaria Vector Research Consortium (PAMVERC), Tanzania
| | - Njelembo J. Mbewe
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Hosiana Mo
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Tanzania
- Pan African Malaria Vector Research Consortium (PAMVERC), Tanzania
| | - Felista Edward
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Tanzania
- Pan African Malaria Vector Research Consortium (PAMVERC), Tanzania
| | - Godwin Sumari
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Tanzania
- Pan African Malaria Vector Research Consortium (PAMVERC), Tanzania
| | - Silvia Mwacha
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Tanzania
- Pan African Malaria Vector Research Consortium (PAMVERC), Tanzania
| | - Agness Msapalla
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Tanzania
- Pan African Malaria Vector Research Consortium (PAMVERC), Tanzania
| | - Benson Mawa
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Tanzania
- Pan African Malaria Vector Research Consortium (PAMVERC), Tanzania
| | - Franklin Mosha
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Tanzania
| | - Johnson Matowo
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Tanzania
- Pan African Malaria Vector Research Consortium (PAMVERC), Tanzania
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Unlu I, Buckner EA, Medina J, Vasquez C, Cabrera A, Romero-Weaver AL, Ramirez D, Kendziorski NL, Kosinski KJ, Fedirko TJ, Ketelsen L, Dorsainvil C, Estep AS. Insecticide resistance of Miami-Dade Culex quinquefasciatus populations and initial field efficacy of a new resistance-breaking adulticide formulation. PLoS One 2024; 19:e0296046. [PMID: 38346028 PMCID: PMC10861066 DOI: 10.1371/journal.pone.0296046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 12/05/2023] [Indexed: 02/15/2024] Open
Abstract
Sporadic outbreaks of human cases of West Nile virus (WNV), primarily vectored by Culex quinquefasciatus Say in suburban and urban areas, have been reported since introduction of the virus into Florida in 2001. Miami-Dade County, Florida is part of one of the largest metropolitan areas in the United States, supports Cx. quinquefasciatus year-round, and recently experienced over 60 human cases of WNV during one outbreak. To facilitate more effective integrated vector management and public health protection, we used the Centers for Disease Control and Prevention (CDC) bottle bioassay method to evaluate the susceptibility of adult Cx. quinquefasciatus collected from 29 locations throughout Miami-Dade County to pyrethroid and organophosphate adulticide active ingredients (AIs) used by Miami-Dade County Mosquito Control. We also determined the frequency of the 1014 knockdown resistance (kdr) mutation for Cx. quinquefasciatus from a subset of 17 locations. We detected resistance to two pyrethroid AIs in all tested locations (permethrin: 27 locations, deltamethrin: 28 locations). The 1014F allele was widely distributed throughout all 17 locations sampled; however, 29.4% of these locations lacked 1014F homozygotes even though phenotypic pyrethroid resistance was present. Organophosphate resistance was more variable; 20.7% of the locations tested were susceptible to malathion, and 33.3% of the populations were susceptible to naled. We subsequently conducted a field trial of ReMoa Tri, a recently approved multiple AI adulticide formulation labelled for resistant mosquitoes, against a mixed location field population of Miami-Dade Cx. quinquefasciatus. Average 24-hr mortality was 65.1 ± 7.2% and 48-hr mortality increased to 85.3 ± 9.1%, indicating good control of these resistant Cx. quinquefasciatus. This current study shows that insecticide resistance is common in local Cx. quinquefasciatus but effective options are available to maintain control during active disease transmission in Miami-Dade County.
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Affiliation(s)
- Isik Unlu
- Miami-Dade County Mosquito Control Division, Miami, Florida, United States of America
| | - Eva A. Buckner
- Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, Florida, United States of America
| | - Johanna Medina
- Miami-Dade County Mosquito Control Division, Miami, Florida, United States of America
| | - Chalmers Vasquez
- Miami-Dade County Mosquito Control Division, Miami, Florida, United States of America
| | - Aimee Cabrera
- Miami-Dade County Mosquito Control Division, Miami, Florida, United States of America
| | - Ana L. Romero-Weaver
- Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, Florida, United States of America
| | - Daviela Ramirez
- Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, Florida, United States of America
| | - Natalie L. Kendziorski
- Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, Florida, United States of America
| | - Kyle J. Kosinski
- Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, Florida, United States of America
| | - T. J. Fedirko
- Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, Florida, United States of America
| | - Leigh Ketelsen
- Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, Florida, United States of America
| | - Chelsea Dorsainvil
- Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, Florida, United States of America
| | - Alden S. Estep
- Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, Gainesville, Florida, United States of America
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12
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Fouet C, Ashu FA, Ambadiang MM, Tchapga W, Wondji CS, Kamdem C. Clothianidin-resistant Anopheles gambiae adult mosquitoes from Yaoundé, Cameroon, display reduced susceptibility to SumiShield® 50WG, a neonicotinoid formulation for indoor residual spraying. BMC Infect Dis 2024; 24:133. [PMID: 38273227 PMCID: PMC10811947 DOI: 10.1186/s12879-024-09030-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND Chronic exposure of mosquito larvae to pesticide residues and cross-resistance mechanisms are major drivers of tolerance to insecticides used for vector control. This presents a concern for the efficacy of clothianidin, an agricultural neonicotinoid prequalified for Indoor Residual Spraying (IRS). METHODS Using standard bioassays, we tested if reduced susceptibility to clothianidin can affect the efficacy of SumiShield® 50WG, one of four new IRS formulations containing clothianidin. We simultaneously monitored susceptibility to clothianidin and to SumiShield 50WG, testing adults of Anopheles gambiae, An. coluzzii and Culex sp sampled from urban, suburban and agricultural areas of Yaoundé, Cameroon. RESULTS We found that in this geographic area, the level of susceptibility to the active ingredient predicted the efficacy of SumiShield 50WG. This formulation was very potent against populations that reached 100% mortality within 72 h of exposure to a discriminating concentration of clothianidin. By contrast, mortality leveled off at 75.4 ± 3.5% within 7 days of exposure to SumiShield 50WG in An. gambiae adults collected from a farm where the spraying of the two neonicotinoids acetamiprid and imidacloprid for crop protection is likely driving resistance to clothianidin. CONCLUSIONS Despite the relatively small geographic extend of the study, the findings suggest that cross-resistance may impact the efficacy of some new IRS formulations and that alternative compounds could be prioritized in areas where neonicotinoid resistance is emerging.
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Affiliation(s)
- Caroline Fouet
- Department of Biological Sciences, The University of Texas at El Paso, 500 W. University Ave, El Paso, TX, 79968, USA
| | - Fred A Ashu
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Marilene M Ambadiang
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Williams Tchapga
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, L3 5QA, UK
| | - Colince Kamdem
- Department of Biological Sciences, The University of Texas at El Paso, 500 W. University Ave, El Paso, TX, 79968, USA.
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Ashu FA, Fouet C, Ambadiang MM, Penlap-Beng V, Kamdem C. Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes. PLoS Negl Trop Dis 2023; 17:e0011737. [PMID: 37976311 PMCID: PMC10656025 DOI: 10.1371/journal.pntd.0011737] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 10/18/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND The standard operating procedure for testing the susceptibility of adult mosquitoes to neonicotinoid or butenolide insecticides recommends using a vegetable oil ester (Mero) as a surfactant. However, there is growing evidence that this adjuvant contains surfactants that can enhance insecticide activity, mask resistance and bias the bioassay. METHODOLOGY/PRINCIPAL FINDINGS Using standard bioassays, we tested the effects of commercial formulations of vegetable oil-based surfactants similar to Mero on the activity of a spectrum of active ingredients including four neonicotinoids (acetamiprid, clothianidin, imidacloprid and thiamethoxam) and two pyrethroids (permethrin and deltamethrin). We found that three different brands of linseed oil soap used as cleaning products drastically enhanced neonicotinoid activity in Anopheles mosquitoes. At 1% (v/v), the surfactant reduced the median lethal concentration, LC50, of clothianidin more than 10-fold both in susceptible and in resistant populations of Anopheles gambiae. At 1% or 0.5% (v/v), linseed oil soap restored the susceptibility of adult mosquitoes fully to clothianidin, thiamethoxam and imidacloprid and partially to acetamiprid. By contrast, adding soap to the active ingredient did not significantly affect the level of resistance to permethrin or deltamethrin suggesting that vegetable oil-based surfactants specifically enhance the potency of some classes of insecticides. CONCLUSIONS/SIGNIFICANCE Our findings indicate that surfactants are not inert ingredients, and their use in susceptibility testing may jeopardize the ability to detect resistance. Further research is needed to evaluate the potential, the limitations and the challenges of using some surfactants as adjuvants to enhance the potency of some chemicals applied in mosquito control.
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Affiliation(s)
- Fred A. Ashu
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé, Yaoundé, Cameroon
| | - Caroline Fouet
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Marilene M. Ambadiang
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé, Yaoundé, Cameroon
| | - Véronique Penlap-Beng
- Department of Biochemistry, Faculty of Science, University of Yaoundé, Yaoundé, Cameroon
| | - Colince Kamdem
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, Texas, United States of America
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14
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Odjo EM, Salako AS, Padonou GG, Yovogan B, Adoha CJ, Adjottin B, Sominahouin AA, Sovi A, Osse R, Kpanou CD, Sagbohan HW, Djenontin A, Agbangla C, Akogbeto MC. What can be learned from the residual efficacy of three formulations of insecticides (pirimiphos-methyl, clothianidin and deltamethrin mixture, and clothianidin alone) in large-scale in community trial in North Benin, West Africa? Malar J 2023; 22:150. [PMID: 37158866 PMCID: PMC10165746 DOI: 10.1186/s12936-023-04572-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 04/24/2023] [Indexed: 05/10/2023] Open
Abstract
BACKGROUND In Alibori and Donga, two departments of high malaria incidence of Northern Benin, pirimiphos-methyl, mixture deltamethrin + clothianidin, as well as clothianidin were used at large scale for IRS. The present study aimed to assess the residual efficacy of these products. METHODS Immatures of Anopheles gambiae sensu lato (s.l.) collected in the communes of Kandi and Gogounou (Department of Alibori), Djougou and Copargo (Department of Donga) were reared until adulthood. Females aged 2-5 days were used for susceptibility tube tests following the WHO protocol. The tests were conducted with deltamethrin (0.05%), bendiocarb (0.1%), pirimiphos-methyl (0.25%) and clothianidin (2% weight per volume). For cone tests performed on cement and mud walls, the An. gambiae Kisumu susceptible strain was used. After the quality control of the IRS performed 1-week post-campaign, the evaluation of the residual activity of the different tested insecticides/mixture of insecticides was conducted on a monthly basis. RESULTS Over the three study years, deltamethrin resistance was observed in all the communes. With bendiocarb, resistance or possible resistance was observed. In 2019 and 2020, full susceptibility to pirimiphos-methyl was observed, while possible resistance to the same product was detected in 2021 in Djougou, Gogounou and Kandi. With clothianidin, full susceptibility was observed 4-6 days post-exposure. The residual activity lasted 4-5 months for pirimiphos-methyl, and 8-10 months for clothianidin and the mixture deltamethrin + clothianidin. A slightly better efficacy of the different tested products was observed on cement walls compared to the mud walls. CONCLUSION Overall, An. gambiae s.l. was fully susceptible to clothianidin, while resistance/possible resistance was observed the other tested insecticides. In addition, clothianidin-based insecticides showed a better residual activity compared to pirimiphos-methyl, showing thus their ability to provide an improved and prolonged control of pyrethroid resistant vectors.
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Affiliation(s)
- Esdras Mahoutin Odjo
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin.
- Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin.
| | | | - Germain Gil Padonou
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin
| | - Boulais Yovogan
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin
| | - Constantin Jésukèdè Adoha
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin
| | - Bruno Adjottin
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin
| | | | - Arthur Sovi
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
- Faculté d'Agronomie de l'Université de Parakou, Parakou, Benin
| | - Razaki Osse
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Université Nationale d'Agriculture de Porto-Novo, Porto-Novo, Benin
| | - Casimir D Kpanou
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin
| | - Hermann W Sagbohan
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin
| | - Armel Djenontin
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin
| | - Clement Agbangla
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Direction Générale de la Recherche Scientifique, Ministère de l'Enseignement Supérieur et de la Recherche Scientifique, Cotonou, Benin
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Fouet C, Ashu F, Ambadiang M, Tchapga W, Wondji C, Kamdem C. Resistance to clothianidin reduces the efficacy of SumiShield ® 50WG, a neonicotinoid formulation for indoor residual spraying, against Anopheles gambiae. RESEARCH SQUARE 2023:rs.3.rs-2847231. [PMID: 37162950 PMCID: PMC10168466 DOI: 10.21203/rs.3.rs-2847231/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Chronic exposure of mosquito larvae to pesticide residues in agricultural areas is often associated with evolution of resistance to insecticides used for vector control. This presents a concern for the efficacy of clothianidin, an agricultural neonicotinoid qualified for Indoor Residual Spraying (IRS). Using standard bioassays, we tested if reduced susceptibility to clothianidin affects the efficacy of SumiShield® 50WG, one of the two newly approved formulations, which contains 50% clothianidin. We simultaneously monitored susceptibility to clothianidin and to SumiShield® 50WG, testing adults of Anopheles gambiae, An. coluzzii and Culex sp collected from urban, suburban and agricultural areas of Yaoundé. We found that the level of susceptibility to the active ingredient predicted the efficacy of SumiShield® 50WG. This formulation was very potent against populations that achieved 100% mortality within 72 h of exposure to a discriminating dose of clothianidin. By contrast, mortality leveled off at 75.4 ± 3.5% within 7 days of exposure to SumiShield® 50WG in An. gambiae adults collected from a farm where spraying of acetamiprid and imidacloprid is driving cross-resistance to clothianidin. These findings indicate that more potent formulations of clothianidin or different insecticides should be prioritized in areas where resistance is emerging.
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16
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Ashu FA, Fouet C, Ambadiang MM, Penlap-Beng V, Kamdem C. Vegetable oil surfactants are synergists that can bias neonicotinoid susceptibility testing in adult mosquitoes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.18.537421. [PMID: 37131639 PMCID: PMC10153115 DOI: 10.1101/2023.04.18.537421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Background The standard operating procedure for testing the susceptibility of adult mosquitoes to clothianidin, a neonicotinoid, recommends using a vegetable oil ester as surfactant. However, it has not yet been determined if the surfactant is an inert ingredient or if it can act as a synergist and bias the test. Methodology/Principal Findings Using standard bioassays, we tested the synergistic effects of a vegetable oil surfactant on a spectrum of active ingredients including four neonicotinoids (acetamiprid, clothianidin, imidacloprid and thiamethoxam) and two pyrethroids (permethrin and deltamethrin). Three different formulations of linseed oil soap used as surfactant were far more effective than the standard insecticide synergist piperonyl butoxide in enhancing neonicotinoid activity in Anopheles mosquitoes. At the concentration used in the standard operating procedure (1% v/v), vegetable oil surfactants lead to more than 10-fold reduction in lethal concentrations, LC 50 and LC 99 , of clothianidin in a multi-resistant field population and in a susceptible strain of Anopheles gambiae . At 1% or 0.5% (v/v), the surfactant restored susceptibility to clothianidin, thiamethoxam and imidacloprid and increased mortality to acetamiprid from 43 ± 5.63% to 89 ± 3.25% (P<0.05) in resistant mosquitoes. By contrast, linseed oil soap had no effect on the level of resistance to permethrin and deltamethrin suggesting that the synergism of vegetable oil surfactants may be specific to neoniconoids. Conclusions/Significance Our findings indicate that vegetable oil surfactants are not inert ingredients in neonicotinoid formulations, and their synergistic effects undermine the ability of standard testing procedures to detect early stages of resistance.
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17
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Portwood NM, Shayo MF, Tungu PK, Mbewe NJ, Mlay G, Small G, Snetselaar J, Kristan M, Levy P, Walker T, Kirby MJ, Kisinza W, Mosha FW, Rowland M, Messenger LA. Multi-centre discriminating concentration determination of broflanilide and potential for cross-resistance to other public health insecticides in Anopheles vector populations. Sci Rep 2022; 12:22359. [PMID: 36572746 PMCID: PMC9792579 DOI: 10.1038/s41598-022-26990-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022] Open
Abstract
Novel insecticides are urgently needed to control insecticide-resistant populations of Anopheles malaria vectors. Broflanilide acts as a non-competitive antagonist of the gamma-aminobutyric acid receptor and has shown prolonged effectiveness as an indoor residual spraying product (VECTRON T500) in experimental hut trials against pyrethroid-resistant vector populations. This multi-centre study expanded upon initial discriminating concentration testing of broflanilide, using six Anopheles insectary colonies (An. gambiae Kisumu KCMUCo, An. gambiae Kisumu NIMR, An. arabiensis KGB, An. arabiensis SENN, An. coluzzii N'Gousso and An. stephensi SK), representing major malaria vector species, to facilitate prospective susceptibility monitoring of this new insecticide; and investigated the potential for cross-resistance to broflanilide via the A296S mutation associated with dieldrin resistance (rdl). Across all vector species tested, the discriminating concentration for broflanilide ranged between LC99 × 2 = 1.126-54.00 μg/ml or LC95 × 3 = 0.7437-17.82 μg/ml. Lower concentrations of broflanilide were required to induce complete mortality of An. arabiensis SENN (dieldrin-resistant), compared to its susceptible counterpart, An. arabiensis KGB, and there was no association between the presence of the rdl mechanism of resistance and survival in broflanilide bioassays, demonstrating a lack of cross-resistance to broflanilide. Study findings provide a benchmark for broflanilide susceptibility monitoring as part of ongoing VECTRON T500 community trials in Tanzania and Benin.
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Affiliation(s)
- Natalie M Portwood
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Magreth F Shayo
- Kilimanjaro Christian Medical University College, Pan African Malaria Vector Research Consortium, Moshi, Tanzania
| | - Patrick K Tungu
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Njelembo J Mbewe
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
- Kilimanjaro Christian Medical University College, Pan African Malaria Vector Research Consortium, Moshi, Tanzania
| | - George Mlay
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Graham Small
- Innovative Vector Control Consortium, Liverpool, UK
| | - Janneke Snetselaar
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
- Innovative Vector Control Consortium, Liverpool, UK
| | - Mojca Kristan
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Prisca Levy
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Thomas Walker
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
- School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, CV4 7AL, UK
| | - Matthew J Kirby
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd., Rockville, MD, 20852, USA
| | - William Kisinza
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Franklin W Mosha
- Kilimanjaro Christian Medical University College, Pan African Malaria Vector Research Consortium, Moshi, Tanzania
| | - Mark Rowland
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Louisa A Messenger
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.
- Department of Environmental and Occupational Health, School of Public Health, University of Nevada, Las Vegas, NV, USA.
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18
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Preventive residual insecticide applications successfully controlled Aedes aegypti in Yucatan, Mexico. Sci Rep 2022; 12:21998. [PMID: 36539478 PMCID: PMC9768150 DOI: 10.1038/s41598-022-26577-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Insecticide-based approaches remain a key pillar for Aedes-borne virus (ABV, dengue, chikungunya, Zika) control, yet they are challenged by the limited effect of traditional outdoor insecticide campaigns responding to reported arboviral cases and by the emergence of insecticide resistance in mosquitoes. A three-arm Phase II unblinded entomological cluster randomized trial was conducted in Merida, Yucatan State, Mexico, to quantify the entomological impact of targeted indoor residual spraying (TIRS, application of residual insecticides in Ae. aegypti indoor resting sites) applied preventively 2 months before the beginning of the arbovirus transmission season. Trial arms involved the use of two insecticides with unrelated modes of action (Actellic 300CS, pirimiphos-methyl, and SumiShield 50WG, clothianidin) and a control arm where TIRS was not applied. Entomological impact was quantified by Prokopack adult collections performed indoors during 10 min per house. Regardless of the insecticide, conducting a preventive TIRS application led to significant reductions in indoor Ae. aegypti densities, which were maintained at the same levels as in the low arbovirus transmission period (Actellic 300CS reduced Ae. aegypti density up to 8 months, whereas SumiShield 50WG up to 6 months). The proportional reduction in Ae. aegypti abundance in treatment houses compared to control houses was 50-70% for Actellic 300CS and 43-63% for SumiShield 50WG. Total operational costs including insecticide ranged from US$4.2 to US$10.5 per house, depending on the insecticide cost. Conducting preventive residual insecticide applications can maintain Ae. aegypti densities at low levels year-round with important implications for preventing ABVs in the Americas and beyond.
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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] [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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Govoetchan R, Fongnikin A, Syme T, Small G, Gbegbo M, Todjinou D, Rowland M, Nimmo D, Padonou GG, Ngufor C. VECTRON™ T500, a new broflanilide insecticide for indoor residual spraying, provides prolonged control of pyrethroid-resistant malaria vectors. Malar J 2022; 21:324. [DOI: 10.1186/s12936-022-04336-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 10/26/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Broflanilide is a newly discovered insecticide with a novel mode of action targeting insect γ-aminobutyric acid receptors. The efficacy of VECTRON™ T500, a wettable powder formulation of broflanilide, was assessed for IRS against wild pyrethroid-resistant malaria vectors in experimental huts in Benin.
Methods
VECTRON™ T500 was evaluated at 100 mg/m2 in mud and cement-walled experimental huts against wild pyrethroid-resistant Anopheles gambiae sensu lato (s.l.) in Covè, southern Benin, over 18 months. A direct comparison was made with Actellic® 300CS, a WHO-recommended micro-encapsulated formulation of pirimiphos-methyl, applied at 1000 mg/m2. The vector population at Covè was investigated for susceptibility to broflanilide and other classes of insecticides used for vector control. Monthly wall cone bioassays were performed to assess the residual efficacy of VECTRON™ T500 using insecticide susceptible An. gambiae Kisumu and pyrethroid-resistant An. gambiae s.l. Covè strains. The study complied with OECD principles of good laboratory practice.
Results
The vector population at Covè was resistant to pyrethroids and organochlorines but susceptible to broflanilide and pirimiphos-methyl. A total of 23,171 free-flying wild pyrethroid-resistant female An. gambiae s.l. were collected in the experimental huts over 12 months. VECTRON™ T500 induced 56%-60% mortality in wild vector mosquitoes in both cement and mud-walled huts. Mortality with VECTRON™ T500 was 62%-73% in the first three months and remained > 50% for 9 months on both substrate-types. By comparison, mortality with Actellic® 300CS was very high in the first three months (72%-95%) but declined sharply to < 40% after 4 months. Using a non-inferiority margin defined by the World Health Organization, overall mortality achieved with VECTRON™ T500 was non-inferior to that observed in huts treated with Actellic® 300CS with both cement and mud wall substrates. Monthly in situ wall cone bioassay mortality with VECTRON™ T500 also remained over 80% for 18 months but dropped below 80% with Actellic® 300CS at 6–7 months post spraying.
Conclusion
VECTRON™ T500 shows potential to provide substantial and prolonged control of malaria transmitted by pyrethroid-resistant mosquito vectors when applied for IRS. Its addition to the current list of WHO-approved IRS insecticides will provide a suitable option to facilitate rotation of IRS products with different modes of action.
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21
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Fongnikin A, Odjo A, Akpi J, Kiki L, Ngufor C. Pirikool® 300 CS, a new long-lasting capsule suspension formulation of the organophosphate insecticide pirimiphos-methyl for indoor residual spraying against pyrethroid-resistant malaria vectors. PLoS One 2022; 17:e0267229. [PMID: 35436317 PMCID: PMC9015130 DOI: 10.1371/journal.pone.0267229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 04/05/2022] [Indexed: 11/18/2022] Open
Abstract
Background Indoor residual spraying (IRS) using a capsule suspension formulation of the organophosphate insecticide, pirimiphos-methyl, has provided substantial malaria control in many communities in Africa. However, only one brand of this product has been recommended by the World Health Organisation for IRS. To help increase the diversity of the portfolio of IRS insecticides and offer suitable options to procurers and malaria vector control programmes, additional product brands of this highly effective and long-lasting insecticide formulation for IRS will be needed. Methods We evaluated the efficacy of Pirikool® 300CS, a new capsule suspension formulation of pirimiphos-methyl developed by Tianjin Yorkool, International Trading, Co., Ltd in standard WHO laboratory bioassays and experimental hut studies. The efficacy of the insecticide applied at 1000mg/m2 was assessed in laboratory bioassays for 6 months on cement, plywood and mud block substrates and for 12 months in cement and mud-walled experimental huts against wild free-flying pyrethroid-resistant Anopheles gambiae sensu lato in Covè, Benin. Actellic® 300CS, a WHO-recommended capsule suspension formulation of pirimiphos-methyl was also tested. WHO cylinder tests were performed to determine the frequency of insecticide resistance in the wild vector population during the hut trial. Results The vector population at the hut station was resistant to pyrethroids but susceptible to pirimiphos-methyl. Overall mortality rates of wild free-flying pyrethroid-resistant An. gambiae (s.l.) entering Pirikool®300CS treated experimental huts during the 12-month trial were 86.7% in cement-walled huts and 88% in mud-walled huts. Mortality of susceptible An. gambiae (Kisumu) and pyrethroid-resistant An. gambiae s.l. (Covè) mosquitoes in monthly wall cone bioassays on Pirikool® 300CS treated hut walls remained over 80% for 10–12 months. The laboratory bioassays corroborated the hut findings with Pirikool® 300CS on mud and wood block substrates but not on cement block substrates. Conclusion Indoor residual spraying with Pirikool® 300CS induced high and prolonged mortality of wild pyrethroid-resistant malaria vectors for 10–12 months. Addition of Pirikool®300CS to the current portfolio of IRS insecticides will provide an extra choice of microencapsulated pirimiphos-methyl for IRS.
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Affiliation(s)
- Augustin Fongnikin
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Pan African Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin
| | - Abibath Odjo
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Joel Akpi
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Pan African Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin
| | - Laurette Kiki
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Pan African Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin
| | - Corine Ngufor
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Pan African Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin
- London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
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22
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Runge M, Thawer SG, Molteni F, Chacky F, Mkude S, Mandike R, Snow RW, Lengeler C, Mohamed A, Pothin E. Sub-national tailoring of malaria interventions in Mainland Tanzania: simulation of the impact of strata-specific intervention combinations using modelling. Malar J 2022; 21:92. [PMID: 35300707 PMCID: PMC8929286 DOI: 10.1186/s12936-022-04099-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 02/23/2022] [Indexed: 11/21/2022] Open
Abstract
Background To accelerate progress against malaria in high burden countries, a strategic reorientation of resources at the sub-national level is needed. This paper describes how mathematical modelling was used in mainland Tanzania to support the strategic revision that followed the mid-term review of the 2015–2020 national malaria strategic plan (NMSP) and the epidemiological risk stratification at the council level in 2018. Methods Intervention mixes, selected by the National Malaria Control Programme, were simulated for each malaria risk strata per council. Intervention mixes included combinations of insecticide-treated bed nets (ITN), indoor residual spraying, larval source management, and intermittent preventive therapies for school children (IPTsc). Effective case management was either based on estimates from the malaria indicator survey in 2016 or set to a hypothetical target of 85%. A previously calibrated mathematical model in OpenMalaria was used to compare intervention impact predictions for prevalence and incidence between 2016 and 2020, or 2022. Results For each malaria risk stratum four to ten intervention mixes were explored. In the low-risk and urban strata, the scenario without a ITN mass campaign in 2019, predicted high increase in prevalence by 2020 and 2022, while in the very-low strata the target prevalence of less than 1% was maintained at low pre-intervention transmission intensity and high case management. In the moderate and high strata, IPTsc in addition to existing vector control was predicted to reduce the incidence by an additional 15% and prevalence by 22%. In the high-risk strata, all interventions together reached a maximum reduction of 76%, with around 70% of that reduction attributable to high case management and ITNs. Overall, the simulated revised NMSP was predicted to achieve a slightly lower prevalence in 2020 compared to the 2015–2020 NMSP (5.3% vs 6.3%). Conclusion Modelling supported the choice of intervention per malaria risk strata by providing impact comparisons of various alternative intervention mixes to address specific questions relevant to the country. The use of a council-calibrated model, that reproduces local malaria trends, represents a useful tool for compiling available evidence into a single analytical platform, that complement other evidence, to aid national programmes with decision-making processes. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04099-5.
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Affiliation(s)
- Manuela Runge
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Sumaiyya G Thawer
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Fabrizio Molteni
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Frank Chacky
- National Malaria Control Programme, Dodoma, Tanzania.,Ministry of Health, Community Development, Gender, Elderly, and Children, Dodoma, Tanzania
| | - Sigsbert Mkude
- National Malaria Control Programme, Dodoma, Tanzania.,Ministry of Health, Community Development, Gender, Elderly, and Children, Dodoma, Tanzania
| | - Renata Mandike
- National Malaria Control Programme, Dodoma, Tanzania.,Ministry of Health, Community Development, Gender, Elderly, and Children, Dodoma, Tanzania
| | - Robert W Snow
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.,Population Health Unit, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Christian Lengeler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Ally Mohamed
- National Malaria Control Programme, Dodoma, Tanzania.,Ministry of Health, Community Development, Gender, Elderly, and Children, Dodoma, Tanzania
| | - Emilie Pothin
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,CHAI, Clinton Health Access Initiative, New York, USA.
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Demissew A, Animut A, Kibret S, Tsegaye A, Hawaria D, Degefa T, Getachew H, Lee MC, Yan G, Yewhalaw D. Evidence of pyrethroid resistance in Anopheles amharicus and Anopheles arabiensis from Arjo-Didessa irrigation scheme, Ethiopia. PLoS One 2022; 17:e0261713. [PMID: 35030201 PMCID: PMC8759678 DOI: 10.1371/journal.pone.0261713] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/08/2021] [Indexed: 11/18/2022] Open
Abstract
Background Indoor residual spraying and insecticide-treated nets are among the key malaria control intervention tools. However, their efficacy is declining due to the development and spread of insecticide resistant vectors. In Ethiopia, several studies reported resistance of An. arabiensis to multiple insecticide classes. However, such data is scarce in irrigated areas of the country where insecticides, pesticides and herbicides are intensively used. Susceptibility of An. gambiae s.l. to existing and new insecticides and resistance mechanisms were assessed in Arjo-Didessa sugarcane plantation area, southwestern Ethiopia. Methods Adult An. gambiae s.l. reared from larval/pupal collections of Arjo-Didessa sugarcane irrigation area and its surrounding were tested for their susceptibility to selected insecticides. Randomly selected An. gambiae s.l. (dead and survived) samples were identified to species using species-specific polymerase chain reaction (PCR) and were further analyzed for the presence of knockdown resistance (kdr) alleles using allele-specific PCR. Results Among the 214 An. gambiae s.l. samples analyzed by PCR, 89% (n = 190) were An. amharicus and 9% (n = 20) were An. arabiensis. Mortality rates of the An. gambiae s.l. exposed to deltamethrin and alphacypermethrin were 85% and 86.8%, respectively. On the other hand, mortalities against pirmiphos-methyl, bendiocarb, propoxur and clothianidin were 100%, 99%, 100% and 100%, respectively. Of those sub-samples (An. amharicus and An. arabiensis) examined for presence of kdr gene, none of them were found to carry the L1014F (West African) allelic mutation. Conclusion Anopheles amharicus and An. arabiensis from Arjo-Didessa sugarcane irrigation area were resistant to pyrethroids which might be synergized by extensive use of agricultural chemicals. Occurrence of pyrethroid resistant malaria vectors could challenge the ongoing malaria control and elimination program in the area unless resistance management strategies are implemented. Given the resistance of An. amharicus to pyrethroids, its behavior and vectorial capacity should be further investigated.
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Affiliation(s)
- Assalif Demissew
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Ambo University, Ambo, Ethiopia
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
- * E-mail: ,
| | - Abebe Animut
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Solomon Kibret
- Program in Public Health, University of California at Irvine, Irvine, California, United States of America
| | - Arega Tsegaye
- Department of Biology, College of Natural Science, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Dawit Hawaria
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
- Yirgalem Hospital Medical College, Yirgalem, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Teshome Degefa
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Hallelujah Getachew
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Department of Medical Laboratory Sciences, Arbaminch College of Health Sciences, Arba Minch, Ethiopia
| | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, California, United States of America
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, California, United States of America
| | - Delenasaw Yewhalaw
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
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24
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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: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [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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25
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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 GLOBAL PUBLIC HEALTH 2022; 2:e0000676. [PMID: 36962736 PMCID: PMC10022262 DOI: 10.1371/journal.pgph.0000676] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [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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26
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Che-Mendoza A, González-Olvera G, Medina-Barreiro A, Arisqueta-Chablé C, Bibiano-Marin W, Correa-Morales F, Kirstein OD, Manrique-Saide P, Vazquez-Prokopec GM. Efficacy of targeted indoor residual spraying with the pyrrole insecticide chlorfenapyr against pyrethroid-resistant Aedes aegypti. PLoS Negl Trop Dis 2021; 15:e0009822. [PMID: 34606519 PMCID: PMC8516273 DOI: 10.1371/journal.pntd.0009822] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/14/2021] [Accepted: 09/19/2021] [Indexed: 11/18/2022] Open
Abstract
Background There is an increased need to mitigate the emergence of insecticide resistance and incorporate new formulations and modes of application to control the urban vector Aedes aegypti. Most research and development of insecticide formulations for the control of Ae. aegypti has focused on their peridomestic use as truck-mounted ULV-sprays or thermal fogs despite the widespread knowledge that most resting Ae. aegypti are found indoors. A recent modification of indoor residual spraying (IRS), termed targeted IRS (TIRS) works by restricting applications to 1.5 m down to the floor and on key Ae. aegypti resting sites (under furniture). TIRS also opens the possibility of evaluating novel residual insecticide formulations currently being developed for malaria IRS. Methods We evaluated the residual efficacy of chlorfenapyr, formulated as Sylando 240SC, for 12 months on free-flying field-derived pyrethroid-resistant Ae. aegypti using a novel experimental house design in Merida, Mexico. On a monthly basis, 600 female Ae. aegypti were released into the houses and left indoors with access to sugar solution for 24 hours. After the exposure period, dead and alive mosquitoes were counted in houses treated with chlorfenapyr as well as untreated control houses to calculate 24-h mortality. An evaluation for these exposed cohorts of surviving mosquitoes was extended up to seven days under laboratory conditions to quantify “delayed mortality”. Results Mean acute (24-h) mortality of pyrethroid-resistant Ae. aegypti ranged 80–97% over 5 months, dropping below 30% after 7 months post-TIRS. If delayed mortality was considered (quantifying mosquito mortality up to 7 days after exposure), residual efficacy was above 90% for up to 7 months post-TIRS application. Generalized Additive Mixed Models quantified a residual efficacy of chlorfenapyr of 225 days (ca. 7.5 months). Conclusions Chlorfenapyr represents a new option for TIRS control of Ae. aegypti in urban areas, providing a highly-effective time of protection against indoor Ae. aegypti females of up to 7 months. Vector control (VC) for managing Aedes aegypti and reducing transmission of Aedes-borne diseases is largely focused on peridomestic insecticide applications. However, the indoor resting behavior of Ae. aegypti and the acceleration of insecticide resistance owed to reduced modes of action have diminished the effectiveness of many VC tools. A targeted Indoor residual spraying (TIRS) modality in experimental housing units was employed to investigate the potential of chlorfenapyr, a pyrrole-class insecticide with known effectiveness to resistant mosquito species. This was the first investigation for chlorfenapyr use against locally resistant Ae. aegypti (Merida, Mexico) with this approach. Two treatment arms were investigated in the present study: TIRS and a control house where only water was sprayed. A comparison of entomological efficacy for TIRS applied to interior perimeter walls below 1.5 m with chlorfenapyr (formulated as Sylando 240SC) at 250 mg/m2 over 12 months was assessed. TIRS chlorfenapyr treatments were highly efficacious and led to acute mortalities (after 24 exposure) above 80% up to 5 months; delayed mortalities (to Ae. aegypti) were monitored over seven days post exposures vs untreated controls. When delayed mortality was considered, residual efficacy of chlorfenapyr extended to 7 months. These data provide evidence that TIRS chlorfenapyr is an effective Aedes management tool that surpassed efficacy profiles for other TIRS insecticides that have been previously reported with this method. Further, Chlorfenapyr emerges as a novel addition to Ae. aegypti VC, and future studies should focus on its effectiveness and residual power as part of Phase II-III TIRS trials.
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Affiliation(s)
- Azael Che-Mendoza
- Unidad Colaborativa para Bioensayos Entomologicos, Universidad Autonoma de Yucatan, Merida, Yucatan, Mexico
| | - Gabriela González-Olvera
- Unidad Colaborativa para Bioensayos Entomologicos, Universidad Autonoma de Yucatan, Merida, Yucatan, Mexico
| | - Anuar Medina-Barreiro
- Unidad Colaborativa para Bioensayos Entomologicos, Universidad Autonoma de Yucatan, Merida, Yucatan, Mexico
| | - Carlos Arisqueta-Chablé
- Unidad Colaborativa para Bioensayos Entomologicos, Universidad Autonoma de Yucatan, Merida, Yucatan, Mexico
| | - Wilberth Bibiano-Marin
- Unidad Colaborativa para Bioensayos Entomologicos, Universidad Autonoma de Yucatan, Merida, Yucatan, Mexico
| | - Fabián Correa-Morales
- Centro Nacional de Programas Preventivos y Control de Enfermedades (CENAPRECE) Secretaria de Salud Mexico, Ciudad de Mexico, Mexico
| | - Oscar D. Kirstein
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
| | - Pablo Manrique-Saide
- Unidad Colaborativa para Bioensayos Entomologicos, Universidad Autonoma de Yucatan, Merida, Yucatan, Mexico
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27
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Zoh MG, Bonneville JM, Tutagata J, Laporte F, Fodjo BK, Mouhamadou CS, Sadia CG, McBeath J, Schmitt F, Horstmann S, Reynaud S, David JP. Experimental evolution supports the potential of neonicotinoid-pyrethroid combination for managing insecticide resistance in malaria vectors. Sci Rep 2021; 11:19501. [PMID: 34593941 PMCID: PMC8484614 DOI: 10.1038/s41598-021-99061-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/20/2021] [Indexed: 11/22/2022] Open
Abstract
The introduction of neonicotinoids for managing insecticide resistance in mosquitoes is of high interest as they interact with a biochemical target not previously used in public health. In this concern, Bayer developed a combination of the neonicotinoid clothianidin and the pyrethroid deltamethrin (brand name Fludora Fusion) as a new vector control tool. Although this combination proved to be efficient against pyrethroid-resistant mosquitoes, its ability to prevent the selection of pyrethroid and neonicotinoid resistance alleles was not investigated. In this context, the objective of this work was to study the dynamics and the molecular mechanisms of resistance of An. gambiae to the separated or combined components of this combination. A field-derived An. gambiae line carrying resistance alleles to multiple insecticides at low frequencies was used as a starting for 33 successive generations of controlled selection. Resistance levels to each insecticide and target site mutation frequencies were monitored throughout the selection process. Cross resistance to other public health insecticides were also investigated. RNA-seq was used to compare gene transcription variations and polymorphisms across all lines. This study confirmed the potential of this insecticide combination to impair the selection of resistance as compared to its two separated components. Deltamethrin selection led to the rapid enrichment of the kdr L1014F target-site mutation. Clothianidin selection led to the over-transcription of multiple cytochrome P450s including some showing high homology with those conferring neonicotinoid resistance in other insects. A strong selection signature associated with clothianidin selection was also observed on a P450 gene cluster previously associated with resistance. Within this cluster, the gene CYP6M1 showed the highest selection signature together with a transcription profile supporting a role in clothianidin resistance. Modelling the impact of point mutations selected by clothianidin on CYP6M1 protein structure showed that selection retained a protein variant with a modified active site potentially enhancing clothianidin metabolism. In the context of the recent deployment of neonicotinoids for mosquito control and their frequent usage in agriculture, the present study highlights the benefit of combining them with other insecticides for preventing the selection of resistance and sustaining vector control activities.
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Affiliation(s)
- Marius Gonse Zoh
- Laboratoire d'Ecologie Alpine (LECA) UMR 5553 CNRS Grenoble-Alpes University, Grenoble, France
| | - Jean-Marc Bonneville
- Laboratoire d'Ecologie Alpine (LECA) UMR 5553 CNRS Grenoble-Alpes University, Grenoble, France
| | - Jordan Tutagata
- Laboratoire d'Ecologie Alpine (LECA) UMR 5553 CNRS Grenoble-Alpes University, Grenoble, France
| | - Frederic Laporte
- Laboratoire d'Ecologie Alpine (LECA) UMR 5553 CNRS Grenoble-Alpes University, Grenoble, France
| | - Behi K Fodjo
- Centre Suisse de La Recherche Scientifique (CSRS), Abidjan, Côte d'Ivoire
| | | | - Christabelle Gba Sadia
- Centre Suisse de La Recherche Scientifique (CSRS), Abidjan, Côte d'Ivoire.,University of Nangui Abrogoua, Abidjan, Côte d'Ivoire
| | - Justin McBeath
- Bayer CropScience Ltd, Cambridge Science Park, Cambridge, UK
| | | | | | - Stephane Reynaud
- Laboratoire d'Ecologie Alpine (LECA) UMR 5553 CNRS Grenoble-Alpes University, Grenoble, France
| | - Jean-Philippe David
- Laboratoire d'Ecologie Alpine (LECA) UMR 5553 CNRS Grenoble-Alpes University, Grenoble, France.
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Efficacy of broflanilide (VECTRON T500), a new meta-diamide insecticide, for indoor residual spraying against pyrethroid-resistant malaria vectors. Sci Rep 2021; 11:7976. [PMID: 33846394 PMCID: PMC8042056 DOI: 10.1038/s41598-021-86935-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/18/2021] [Indexed: 11/09/2022] Open
Abstract
The rotational use of insecticides with different modes of action for indoor residual spraying (IRS) is recommended for improving malaria vector control and managing insecticide resistance. Insecticides with new chemistries are urgently needed. Broflanilide is a newly discovered insecticide under consideration. We investigated the efficacy of a wettable powder (WP) formulation of broflanilide (VECTRON T500) for IRS on mud and cement wall substrates in laboratory and experimental hut studies against pyrethroid-resistant malaria vectors in Benin, in comparison with pirimiphos-methyl CS (Actellic 300CS). There was no evidence of cross-resistance to pyrethroids and broflanilide in CDC bottle bioassays. In laboratory cone bioassays, broflanilide WP-treated substrates killed > 80% of susceptible and pyrethroid-resistant An. gambiae sl for 6–14 months. At application rates of 100 mg/m2 and 150 mg/m2, mortality of wild pyrethroid-resistant An. gambiae sl entering experimental huts in Covè, Benin treated with VECTRON T500 was similar to pirimiphos-methyl CS (57–66% vs. 56%, P > 0.05). Throughout the 6-month hut trial, monthly wall cone bioassay mortality on VECTRON T500 treated hut walls remained > 80%. IRS with broflanilide shows potential to significantly improve the control of malaria transmitted by pyrethroid-resistant mosquito vectors and could thus be a crucial addition to the current portfolio of IRS insecticides.
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29
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Wagman JM, Varela K, Zulliger R, Saifodine A, Muthoni R, Magesa S, Chaccour C, Gogue C, Tynuv K, Seyoum A, Dengela D, Saúte F, Richardson JH, Fornadel C, Linton YM, Slutsker L, Candrinho B, Robertson M. Reduced exposure to malaria vectors following indoor residual spraying of pirimiphos-methyl in a high-burden district of rural Mozambique with high ownership of long-lasting insecticidal nets: entomological surveillance results from a cluster-randomized trial. Malar J 2021; 20:54. [PMID: 33478533 PMCID: PMC7819201 DOI: 10.1186/s12936-021-03583-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 01/06/2021] [Indexed: 02/02/2023] Open
Abstract
Background The need to develop new products and novel approaches for malaria vector control is recognized as a global health priority. One approach to meeting this need has been the development of new products for indoor residual spraying (IRS) with novel active ingredients for public health. While initial results showing the impact of several of these next-generation IRS products have been encouraging, questions remain about how to best deploy them for maximum impact. To help address these questions, a 2-year cluster-randomized controlled trial to measure the impact of IRS with a microencapsulated formulation of pirimiphos-methyl (PM) in an area with high ownership of long-lasting insecticidal nets (LLINs) was conducted in a high-transmission district of central Mozambique with pyrethroid resistant vectors. Presented here are the results of the vector surveillance component of the trial. Methods The 2 year, two-armed trial was conducted in Mopeia District, Zambezia Province, Mozambique. In ten sentinel villages, five that received IRS with PM in October–November 2016 and again in October–November 2017 and five that received no IRS, indoor light trap collections and paired indoor-outdoor human landing collections catches (HLCs) were conducted monthly from September 2016 through October 2018. A universal coverage campaign in June 2017, just prior to the second spray round, distributed 131,540 standard alpha-cypermethrin LLINs across all study villages and increased overall net usage rates in children under 5 years old to over 90%. Results The primary malaria vector during the trial was Anopheles funestus sensu lato (s.l.), and standard World Health Organization (WHO) tube tests with this population indicated variable but increasing resistance to pyrethroids (including alpha-cypermethrin, from > 85% mortality in 2017 to 7% mortality in 2018) and uniform susceptibility to PM (100% mortality in both years). Over the entire duration of the study, IRS reduced An. funestus s.l. densities by 48% (CI95 33–59%; p < 0.001) in indoor light traps and by 74% (CI95 38–90%; p = 0.010) during indoor and outdoor HLC, though in each study year reductions in vector density were consistently greatest in those months immediately following the IRS campaigns and waned over time. Overall there was no strong preference for An. funestus to feed indoors or outdoors, and these biting behaviours did not differ significantly across study arms: observed indoor-outdoor biting ratios were 1.10 (CI95 1.00–1.21) in no-IRS villages and 0.88 (CI95 0.67–1.15) in IRS villages. The impact of IRS was consistent in reducing HLC exposures both indoors (75% reduction: CI95 47–88%; p = 0. < 0.001) and outdoors (68% reduction: CI95 22–87%; p = 0.012). While substantially fewer Anopheles gambiae s.l. were collected during the study, trends show a similar impact of IRS on this key vector group as well, with a 33% (CI95 7–53%; p = 0.019) reduction in mosquitoes collected in light traps and a non-statistically significant 39% reduction (p = 0.249) in HLC landing rates. Conclusion IRS with PM used in addition to pyrethroid-only LLINs substantially reduced human exposures to malaria vectors during both years of the cluster-randomized controlled trial in Mopeia—a high-burden district where the primary vector, An. funestus s.l., was equally likely to feed indoors or outdoors and demonstrated increasing resistance to pyrethroids. Findings suggest that IRS with PM can provide effective vector control, including in some settings where pyrethroid-only ITNs are widely used. Trial registrationclinicaltrials.gov, NCT02910934. Registered 22 September 2016, https://www.clinicaltrials.gov/ct2/show/NCT02910934.
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Affiliation(s)
| | | | - Rose Zulliger
- US President's Malaria Initiative, US Centers for Disease Control and Prevention, Maputo, Mozambique
| | - Abuchahama Saifodine
- US President's Malaria Initiative, US Agency for International Development, Maputo, Mozambique
| | - Rodaly Muthoni
- PMI VectorLink Project, Abt Associates, Maputo, Mozambique
| | - Stephen Magesa
- PMI VectorLink Project, Abt Associates, Maputo, Mozambique
| | - Carlos Chaccour
- Centro de Investigação Em Saúde de Manhiça, Maputo, Mozambique.,Barcelona Institute for Global Health, Barcelona, Spain
| | | | | | - Aklilu Seyoum
- PMI VectorLink Project, Abt Associates, Bethesda, MD, USA
| | - Dereje Dengela
- PMI VectorLink Project, Abt Associates, Bethesda, MD, USA
| | - Francisco Saúte
- Centro de Investigação Em Saúde de Manhiça, Maputo, Mozambique
| | | | | | - Yvonne-Marie Linton
- Walter Reed Biosystematics Unit, Suitland, MD, USA.,Smithsonian Institution-National Museum of Natural History, Washington, DC, USA
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Kamaraju R, Pant CS, Uragayala S, Baharia RK, Srivastava HC, Yadav RS. Small-scale field evaluation of the entomological efficacy and the residual activity of Fludora ® Fusion WP-SB indoor residual spraying against Anopheles culicifacies s.l. in Gujarat, India. Trop Med Int Health 2021; 26:469-477. [PMID: 33423364 DOI: 10.1111/tmi.13549] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To evaluate the entomological efficacy and the residual activity of indoor residual spraying with Fludora® Fusion 562.5 WP-SB, a combination formulation containing clothianidin, a neonicotinoid and deltamethrin, a pyrethroid, against the main rural malaria vector, Anopheles culicifacies s.l., in India in a small-scale trial. METHODS In three study villages, suitable households were randomly allocated to five treatments: Fludora® Fusion 562.5 WP-SB (target dose 225 mg active ingredient AI/m2 ); clothianidin 70 WG (target dose 200 mg AI/m2 ); K-Othrine 250 WG (deltamethrin, target dose 25 mg AI/m2 ); Ficam VC 80 WP-SB (bendiocarb, target dose 400 mg AI/m2 ) and unsprayed control. Insecticides were sprayed by hand compression sprayers with control flow valves and 8002E nozzles. Post-spray cone bioassays were done on insecticide-treated walls using a colonised, deltamethrin-resistant strain of An. culicifacies. Mosquitoes were collected from treated rooms by different methods. The insecticide content on filter papers collected from the sprayed walls was determined by chemical assay to assess the spray quality. RESULTS The ratios of applied to target doses of insecticides were within 0.84 to 1.4, showing a good spray quality. The cone bioassays revealed residual action lasting 7 months for all insecticides without significant differences in mortality between different surfaces treated nor between the four treatment arms (P > 0.05). Considering all entomological parameters such as indoor resting density, excito-repellency, blood-feeding inhibition and delayed mortality, the overall efficacy of Fludora® Fusion WG-SB was equal or better compared with other insecticides. CONCLUSIONS Fludora® Fusion showed overall equal or better efficacy than deltamethrin and bendiocarb alone against a pyrethroid-resistant malaria vector population and can be considered as an alternative product for management of pyrethroid resistance in malaria vectors.
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Affiliation(s)
| | - Chandra Shekhar Pant
- ICMR-National Institute of Malaria Research Field Unit, Civil Hospital, Nadiad, India
| | - Sreehari Uragayala
- ICMR-National Institute of Malaria Research Field Unit, Poojanahalli, India
| | | | | | - Rajpal S Yadav
- Department of Control of Neglected Tropical Diseases, WHO, Geneva, Switzerland
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Lees RS, Ambrose P, Williams J, Morgan J, Praulins G, Ingham VA, Williams CT, Logan RAE, Ismail HM, Malone D. Tenebenal: a meta-diamide with potential for use as a novel mode of action insecticide for public health. Malar J 2020; 19:398. [PMID: 33168015 PMCID: PMC7654575 DOI: 10.1186/s12936-020-03466-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 10/27/2020] [Indexed: 01/21/2023] Open
Abstract
Background There is an urgent need for insecticides with novel modes of action against mosquito vectors. Broflanilide is a meta-diamide, discovered and named Tenebenal™ by Mitsui Chemicals Agro, Inc., which has been identified as a candidate insecticide for use in public health products. Methods To evaluate its potential for use in public health, Tenebenal™ was screened using an array of methodologies against Anopheles and Aedes strains. Initially it was assessed for intrinsic efficacy by topical application. Tarsal contact bioassays were then conducted to further investigate its efficacy, as well as its potency and speed of action. The potential of the compound for use in indoor residual spray (IRS) applications was investigated by testing the residual efficacy of a prototype IRS formulation on a range of typical house building substrates, and its potential for use in long-lasting insecticidal nets (LLIN) was tested using dipped net samples. Finally, bioassays using well-characterized insecticide-resistant mosquito strains and an in silico screen for mutations in the insecticide’s target site were performed to assess the risk of cross-resistance to Tenebenal™. Results Tenebenal™ was effective as a tarsal contact insecticide against both Aedes and Anopheles mosquitoes, with no apparent cross-resistance caused by mechanisms that have evolved to insecticides currently used in vector control. Topical application showed potent intrinsic activity against a Kisumu reference strain and an insecticide-resistant strain of Anopheles gambiae. Applied to filter paper in a WHO tube bioassay, Tenebenal™ was effective in killing 100% of susceptible and resistant strains of An. gambiae and Aedes aegypti at a concentration of 0.01%. The discriminating concentration of 11.91 µg/bottle shows it to be very potent relative to chemistries previously identified as having potential for vector control. Mortality occurs within 24 h of exposure, 80% of this mortality occurring within the first 10 h, a speed of kill somewhat slower than seen with pyrethroids due to the mode of action. The potential of Tenebenal™ for development in LLIN and IRS products was demonstrated. At least 12 months residual efficacy of a prototype IRS formulation applied at concentrations up to 200 mg of AI/sq m was demonstrated on a range of representative wall substrates, and up to 18 months on more inert substrates. A dipped net with an application rate of around 2 g/sq m Tenebenal™ killed 100% of exposed mosquitoes within a 3-min exposure in a WHO cone test. Conclusions Tenebenal™ is a potent insecticide against adult Aedes and Anopheles mosquitoes, including strains resistant to classes of insecticide currently used in vector control. The compound has shown great potential in laboratory assessment and warrants further investigation into development for the control of pyrethroid-resistant mosquitoes.
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Affiliation(s)
| | | | | | - John Morgan
- Liverpool School of Tropical Medicine (LSTM), Liverpool, UK
| | | | | | | | | | | | - David Malone
- Bill & Melinda Gates Foundation, Seattle, USA.,Innovative Vector Control Consortium (IVCC), LSTM, Liverpool, UK
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Adedeji EO, Ogunlana OO, Fatumo S, Beder T, Ajamma Y, Koenig R, Adebiyi E. Anopheles metabolic proteins in malaria transmission, prevention and control: a review. Parasit Vectors 2020; 13:465. [PMID: 32912275 PMCID: PMC7488410 DOI: 10.1186/s13071-020-04342-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 09/01/2020] [Indexed: 12/21/2022] Open
Abstract
The increasing resistance to currently available insecticides in the malaria vector, Anopheles mosquitoes, hampers their use as an effective vector control strategy for the prevention of malaria transmission. Therefore, there is need for new insecticides and/or alternative vector control strategies, the development of which relies on the identification of possible targets in Anopheles. Some known and promising targets for the prevention or control of malaria transmission exist among Anopheles metabolic proteins. This review aims to elucidate the current and potential contribution of Anopheles metabolic proteins to malaria transmission and control. Highlighted are the roles of metabolic proteins as insecticide targets, in blood digestion and immune response as well as their contribution to insecticide resistance and Plasmodium parasite development. Furthermore, strategies by which these metabolic proteins can be utilized for vector control are described. Inhibitors of Anopheles metabolic proteins that are designed based on target specificity can yield insecticides with no significant toxicity to non-target species. These metabolic modulators combined with each other or with synergists, sterilants, and transmission-blocking agents in a single product, can yield potent malaria intervention strategies. These combinations can provide multiple means of controlling the vector. Also, they can help to slow down the development of insecticide resistance. Moreover, some metabolic proteins can be modulated for mosquito population replacement or suppression strategies, which will significantly help to curb malaria transmission.
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Affiliation(s)
- Eunice Oluwatobiloba Adedeji
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State Nigeria
- Department of Biochemistry, Covenant University, Ota, Ogun State Nigeria
| | - Olubanke Olujoke Ogunlana
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State Nigeria
- Department of Biochemistry, Covenant University, Ota, Ogun State Nigeria
| | - Segun Fatumo
- Department of Non-Communicable Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel St, Bloomsbury, London, UK
| | - Thomas Beder
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Yvonne Ajamma
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State Nigeria
| | - Rainer Koenig
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Ezekiel Adebiyi
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State Nigeria
- Computer and Information Sciences, Covenant University, Ota, Ogun State Nigeria
- Division of Applied Bioinformatics, German Cancer Research Center (DKFZ), G200, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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Matowo NS, Tanner M, Munhenga G, Mapua SA, Finda M, Utzinger J, Ngowi V, Okumu FO. Patterns of pesticide usage in agriculture in rural Tanzania call for integrating agricultural and public health practices in managing insecticide-resistance in malaria vectors. Malar J 2020; 19:257. [PMID: 32677961 PMCID: PMC7364647 DOI: 10.1186/s12936-020-03331-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/09/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Unrestricted use of pesticides in agriculture is likely to increase insecticide resistance in mosquito vectors. Unfortunately, strategies for managing insecticide resistance in agriculture and public health sectors lack integration. This study explored the types and usage of agricultural pesticides, and awareness and management practices among retailers and farmers in Ulanga and Kilombero districts in south-eastern Tanzania, where Anopheles mosquitoes are resistant to pyrethroids. METHODS An exploratory sequential mixed-methods approach was employed. First, a survey to characterize pesticide stocks was conducted in agricultural and veterinary (agrovet) retail stores. Interviews to assess general knowledge and practices regarding agricultural pesticides were performed with 17 retailers and 30 farmers, followed by a survey involving 427 farmers. Concurrently, field observations were done to validate the results. RESULTS Lambda-cyhalothrin, cypermethrin (both pyrethroids) and imidacloprids (neonicotinoids) were the most common agricultural insecticides sold to farmers. The herbicide glyphosate (amino-phosphonates) (59.0%), and the fungicides dithiocarbamate and acylalanine (54.5%), and organochlorine (27.3%) were also readily available in the agrovet shops and widely used by farmers. Although both retailers and farmers had at least primary-level education and recognized pesticides by their trade names, they lacked knowledge on pest control or proper usage of these pesticides. Most of the farmers (54.4%, n = 316) relied on instructions from pesticides dealers. Overall, 93.7% (400) farmers practised pesticides mixing in their farms, often in close proximity to water sources. One-third of the farmers disposed of their pesticide leftovers (30.0%, n = 128) and most farmers discarded empty pesticide containers into rivers or nearby bushes (55.7%, n = 238). CONCLUSION Similarities of active ingredients used in agriculture and malaria vector control, poor pesticide management practices and low-levels of awareness among farmers and pesticides retailers might enhance the selection of insecticide resistance in malaria vectors. This study emphasizes the need for improving awareness among retailers and farmers on proper usage and management of pesticides. The study also highlights the need for an integrated approach, including coordinated education on pesticide use, to improve the overall management of insecticide resistance in both agricultural and public health sectors.
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Affiliation(s)
- Nancy S Matowo
- Environmental Health & Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania.
- Swiss Tropical and Public Health Institute, Basel, Switzerland.
- University of Basel, Basel, Switzerland.
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK.
| | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Givemore Munhenga
- Wits Research Institute for Malaria, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Salum A Mapua
- Environmental Health & Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
| | - Marceline Finda
- Environmental Health & Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Vera Ngowi
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Fredros O Okumu
- Environmental Health & Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
- School of Life Science and Bioengineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
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Ngufor C, Fongnikin A, Hobbs N, Gbegbo M, Kiki L, Odjo A, Akogbeto M, Rowland M. Indoor spraying with chlorfenapyr (a pyrrole insecticide) provides residual control of pyrethroid-resistant malaria vectors in southern Benin. Malar J 2020; 19:249. [PMID: 32660479 PMCID: PMC7359555 DOI: 10.1186/s12936-020-03325-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/07/2020] [Indexed: 11/10/2022] Open
Abstract
Background New classes of insecticides with novel modes of action, which can provide effective and prolonged control of insecticide-resistant malaria vector populations, are urgently needed for indoor residual spraying. Such insecticides can be included in a rotation plan to manage and prevent further development of resistance in mosquito vectors of malaria. Chlorfenapyr, a novel pyrrole insecticide with a unique mode of action, is being developed as a long-lasting IRS formulation. Methods The efficacy of several formulations of chlorfenapyr alone and as mixtures with alpha-cypermethrin were evaluated in an experimental hut trial against wild pyrethroid-resistant Anopheles gambiae sensu lato in Cové, Benin, in an attempt to identify the most effective and long-lasting formulations for IRS. The trial lasted 12 months. A comparison was made with alpha-cypermethrin and bendiocarb formulations. CDC bottle bioassays were performed to investigate cross-resistance to chlorfenapyr in the local vector population. Results Mortality rates in World Health Organization (WHO) cylinder bioassays were < 5% with pyrethroids due to high levels of pyrethroid resistance, but > 95% with bendiocarb thus confirming susceptibility to carbamates in the vector population. CDC bottle bioassays showed no cross-resistance between pyrethroids and chlorfenapyr. Overall mortality of free-flying mosquitoes entering the experimental huts over the 12-month trial was 4% with alpha-cypermethrin and 12% with bendiocarb. The chlorfenapyr solo-formulations induced significantly higher levels of mortality (38–46%) compared to the bendiocarb (12% P < 0.001) and to the mixture formulations (18–22%, P < 0.05). The original Sylando 240SC formulation of chlorfenapyr was more efficacious than all other novel chlorfenapyr formulations tested. Bendiocarb induced > 80% mortality in the first month, but this declined sharply to < 20% by the third month while the mortality rates achieved with the chlorfenapyr formulations (38–46%) were persistent lasting 7–10 months. The mixtures induced significantly lower percentage mortality than chlorfenapyr-solo formulations. Wall cone bioassays only showed mortality rates that were consistent with chlorfenapyr IRS treated huts when the exposure time was increased to 2 h. Conclusion Indoor residual spraying with chlorfenapyr (Sylando® 240SC) provides moderate but prolonged control of pyrethroid-resistant malaria vectors compared to pyrethroid and bendiocarb IRS. Wall cone bioassays on chlorfenapyr-treated walls required longer exposure times of 2 h than the customary 30 min indicating that WHO guidelines on residual cone bioassays need to be more insecticide-specific.
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Affiliation(s)
- Corine Ngufor
- London School of Hygiene and Tropical Medicine (LSHTM), London, UK. .,Centre de Recherches Entomologiques de Cotonou (CREC), Cotonou, Benin. .,Panafrican Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin.
| | - Augustin Fongnikin
- Centre de Recherches Entomologiques de Cotonou (CREC), Cotonou, Benin.,Panafrican Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin
| | - Neil Hobbs
- London School of Hygiene and Tropical Medicine (LSHTM), London, UK.,Centre de Recherches Entomologiques de Cotonou (CREC), Cotonou, Benin
| | - Martial Gbegbo
- Centre de Recherches Entomologiques de Cotonou (CREC), Cotonou, Benin.,Panafrican Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin
| | - Laurette Kiki
- Centre de Recherches Entomologiques de Cotonou (CREC), Cotonou, Benin.,Panafrican Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin
| | - Abibath Odjo
- Centre de Recherches Entomologiques de Cotonou (CREC), Cotonou, Benin.,Panafrican Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin
| | - Martin Akogbeto
- Centre de Recherches Entomologiques de Cotonou (CREC), Cotonou, Benin.,Panafrican Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin
| | - Mark Rowland
- London School of Hygiene and Tropical Medicine (LSHTM), London, UK.,Panafrican Malaria Vector Research Consortium (PAMVERC), Cotonou, Benin
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Deguenon JM, Azondekon R, Agossa FR, Padonou GG, Anagonou R, Ahoga J, N’dombidje B, Akinro B, Stewart DA, Wang B, Gittins D, Tihomirov L, Apperson CS, McCord MG, Akogbeto MC, Roe RM. Imergard TMWP: A Non-Chemical Alternative for an Indoor Residual Spray, Effective against Pyrethroid-Resistant Anopheles gambiae (s.l.) in Africa. INSECTS 2020; 11:E322. [PMID: 32456154 PMCID: PMC7290382 DOI: 10.3390/insects11050322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/29/2020] [Accepted: 05/18/2020] [Indexed: 11/17/2022]
Abstract
Malaria is the deadliest mosquito-borne disease and kills predominantly people in sub-Saharan Africa (SSA). The now widespread mosquito resistance to pyrethroids, with rapidly growing resistance to other insecticide classes recommended by the World Health Organization (WHO), may overturn the successes gained in mosquito control in recent years. It is of utmost importance to search for new, inexpensive, and safe alternatives, with new modes of action, that might improve the efficacy of current insecticides. The efficacy of a novel mechanical insecticidal mineral derived from volcanic rock, ImergardTMWP, was investigated to determine its efficacy as a stand-alone residual wall spray and as a mixture with deltamethrin (K-Othrine® Polyzone) in experimental huts in Cove, Benin. The evaluation was conducted with susceptible (Kisumu) and wild-type Anopheles gambiae (s.l.). Deltamethrin applied alone demonstrated 40-45% mortality (at 72 h post-exposure) during the first four months, which declined to 25% at six months for wild An. gambiae from Cove. ImergardTMWP alone and mixed with deltamethrin, under the same assay conditions, produced 79-82% and 73-81% mortality, respectively, during the same six-month period. ImergardTMWP met the 80% WHO bio-efficacy threshold for residual activity for the first five months with 78% residual activity at six months. ImergardTMWP can be used as a mixture with chemical insecticides or as a stand-alone pesticide for mosquito control in Africa.
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Affiliation(s)
- Jean M. Deguenon
- Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA; (J.M.D.); (C.S.A.)
| | - Roseric Azondekon
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Fiacre R. Agossa
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Gil G. Padonou
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Rodrigue Anagonou
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Juniace Ahoga
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Boris N’dombidje
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Bruno Akinro
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - David A. Stewart
- Imerys Filtration Minerals, Inc., Roswell, GA 30076, USA; (D.A.S.); (B.W.); (D.G.); (L.T.)
| | - Bo Wang
- Imerys Filtration Minerals, Inc., Roswell, GA 30076, USA; (D.A.S.); (B.W.); (D.G.); (L.T.)
| | - David Gittins
- Imerys Filtration Minerals, Inc., Roswell, GA 30076, USA; (D.A.S.); (B.W.); (D.G.); (L.T.)
| | - Larissa Tihomirov
- Imerys Filtration Minerals, Inc., Roswell, GA 30076, USA; (D.A.S.); (B.W.); (D.G.); (L.T.)
| | - Charles S. Apperson
- Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA; (J.M.D.); (C.S.A.)
| | - Marian G. McCord
- College of Natural Resources, Campus Box 8001, 2820 Faucette Drive, North Carolina State University, Raleigh, NC 27695, USA;
| | - Martin C. Akogbeto
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - R. Michael Roe
- Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA; (J.M.D.); (C.S.A.)
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South A, Lees R, Garrod G, Carson J, Malone D, Hastings I. The role of windows of selection and windows of dominance in the evolution of insecticide resistance in human disease vectors. Evol Appl 2020; 13:738-751. [PMID: 32211064 PMCID: PMC7086049 DOI: 10.1111/eva.12897] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 10/25/2019] [Accepted: 10/28/2019] [Indexed: 01/23/2023] Open
Abstract
Persistent insecticides sprayed onto house walls, and incorporated into insecticide-treated bednets, provide long-acting, cost-effective control of vector-borne diseases such as malaria and leishmaniasis. The high concentrations that occur immediately postdeployment may kill both resistant and susceptible insects. However, insecticide concentration, and therefore killing ability, declines in the months after deployment. As concentrations decline, resistant insects start to survive, while susceptible insects are still killed. The period of time after deployment, within which the mortality of resistant individuals is lower than that of susceptible ones, has been termed the "window of selection" in other contexts. It is recognized as driving resistance in bacteria and malaria parasites, both of which are predominantly haploid. We argue that paying more attention to these mortality differences can help understand the evolution of insecticide resistance. Because insects are diploid, resistance encoded by single genes generates heterozygotes. This gives the potential for a narrower "window of dominance," within the window of selection, where heterozygote mortality is lower than that of susceptible homozygotes. We explore the general properties of windows of selection and dominance in driving resistance. We quantify their likely effect using data from new laboratory experiments and published data from the laboratory and field. These windows can persist months or years after insecticide deployments. Differential mortalities of resistant, susceptible and heterozygous genotypes, after public health deployments, constitute a major challenge to controlling resistance. Greater attention to mortality differences by genotype would inform strategies to reduce the evolution of resistance to existing and new insecticides.
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Affiliation(s)
- Andy South
- Liverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Rosemary Lees
- Liverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Gala Garrod
- Liverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | | | - David Malone
- Innovative Vector Control Consortium (IVCC)LiverpoolUK
- Present address:
Bill & Melinda Gates FoundationLondonUK
| | - Ian Hastings
- Liverpool School of Tropical Medicine (LSTM)LiverpoolUK
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37
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Salako AS, Dagnon F, Sovi A, Padonou GG, Aïkpon R, Ahogni I, Syme T, Govoétchan R, Sagbohan H, Sominahouin AA, Akinro B, Iyikirenga L, Agossa F, Akogbeto MC. Efficacy of Actellic 300 CS-based indoor residual spraying on key entomological indicators of malaria transmission in Alibori and Donga, two regions of northern Benin. Parasit Vectors 2019; 12:612. [PMID: 31888730 PMCID: PMC6937814 DOI: 10.1186/s13071-019-3865-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 12/19/2019] [Indexed: 11/25/2022] Open
Abstract
Background The current study shows the results of three years of IRS entomological monitoring (2016, before intervention; 2017 and 2018, after intervention) performed in Alibori and Donga, northern Benin. Methods Mosquito collections were performed on a monthly basis using human landing catches and pyrethrum spray catches in six districts including four treated with Actellic 300 CS (Kandi, Gogounou, Djougou and Copargo) and two untreated (Bembèrèkè and Kouandé) which served as control sites. Key transmission indicators of Anopheles gambiae (s.l.) as well as the residual activity of Actellic 300 CS assessed through WHO cone tests, were determined. Results The residual efficacy duration of Actellic 300 CS after the two IRS campaigns (2017 and 2018) was 4–5 months (May–September). The parity rate and the sporozoite index of An. gambiae (s.l.) were 36.62% and 0.71%, respectively, after the first spray round in treated areas compared to 57.24% and 3.7%, respectively, in the control areas (P < 0.0001). The same trend was observed after the second spray round. After the first spray round, each person received 1.6 infective bites/month (ib/m) in the treated areas against 12.11 ib/m in the control areas, resulting in a reduction rate of 86.78%. Similarly, the entomological inoculation rate was 1.5 ib/m after the second spray round in the treated areas vs 9.75 ib/m in the control areas, corresponding to a reduction of 84.61%. A decrease in the parity rate (46.26%), sporozoite index (85.75%) and EIR (87.27%) was observed for An. gambiae (s.l.) after the first round of IRS (June–October 2017) compared to the pre-intervention period (June–October 2016). The density of An. gambiae (s.l.) ranged between 0.38–0.48 per house in treated areas vs 1.53–1.76 An. gambiae (s.l.) per house respectively after the first and second IRS rounds. Conclusions This study showed the positive impact of IRS in reducing key entomological parameters of malaria transmission in Alibori and Donga. However, the considerable blood-feeding rate of An. gambiae (s.l.) in spray areas, stress the need for the population to sleep under long-lasting insecticidal nets (LLINs) in addition, to prevent from mosquito bites which did not succeed in resting on sprayed walls.
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Affiliation(s)
- Albert Sourou Salako
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Cotonou, Benin.
| | - Fortune Dagnon
- USA President's Malaria Initiative, USA Agency for International Development, Cotonou, Benin
| | - Arthur Sovi
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin.,Faculty of Agronomy, University of Parakou, BP 123, Parakou, Benin.,Disease Control Department, Faculty of Infectious & Tropical Diseases, The London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Gil Germain Padonou
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin.,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Cotonou, Benin
| | - Rock Aïkpon
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin.,Université Nationale des Sciences, Technologies, Ingénierie et Mathématiques, Abomey, Bénin
| | - Idelphonse Ahogni
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin.,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Cotonou, Benin
| | - Thomas Syme
- Disease Control Department, Faculty of Infectious & Tropical Diseases, The London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Renaud Govoétchan
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin.,Faculty of Agronomy, University of Parakou, BP 123, Parakou, Benin
| | - Herman Sagbohan
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin.,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Cotonou, Benin
| | - André Aimé Sominahouin
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin.,Faculté des Sciences Humaines et Sociales de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin
| | - Bruno Akinro
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin
| | | | - Fiacre Agossa
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin.,PMI VectorLink Project, Abt Associates, Kinshasa, Democratic Republic of Congo
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Oxborough RM, Seyoum A, Yihdego Y, Dabire R, Gnanguenon V, Wat'senga F, Agossa FR, Yohannes G, Coleman S, Samdi LM, Diop A, Faye O, Magesa S, Manjurano A, Okia M, Alyko E, Masendu H, Baber I, Sovi A, Rakotoson JD, Varela K, Abong'o B, Lucas B, Fornadel C, Dengela D. Susceptibility testing of Anopheles malaria vectors with the neonicotinoid insecticide clothianidin; results from 16 African countries, in preparation for indoor residual spraying with new insecticide formulations. Malar J 2019; 18:264. [PMID: 31370898 PMCID: PMC6670198 DOI: 10.1186/s12936-019-2888-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/22/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In 2017, more than 5 million house structures were sprayed through the U.S. President's Malaria Initiative, protecting more than 21 million people in sub-Saharan Africa. New IRS formulations, SumiShield™ 50WG and Fludora Fusion™ WP-SB, became World Health Organization (WHO) prequalified vector control products in 2017 and 2018, respectively. Both formulations contain the neonicotinoid active ingredient, clothianidin. The target site of neonicotinoids represents a novel mode of action for vector control, meaning that cross-resistance through existing mechanisms is less likely. In preparation for rollout of clothianidin formulations as part of national IRS rotation strategies, baseline susceptibility testing was conducted in 16 countries in sub-Saharan Africa. METHODS While work coordinated by the WHO is ongoing to develop a suitable bottle bioassay procedure, there was no published guidance regarding clothianidin susceptibility procedures or diagnostic concentrations. Therefore, a protocol was developed for impregnating filter papers with 2% w/v SumiShield™ 50WG dissolved in distilled water. Susceptibility tests were conducted using insectary-reared reference Anopheles and wild collected malaria vector species. All tests were conducted within 24 h of treating papers, with mortality recorded daily for 7 days, due to the slow-acting nature of clothianidin against mosquitoes. Anopheles gambiae sensu lato (s.l.) adults from wild collected larvae were tested in 14 countries, with wild collected F0 Anopheles funestus s.l. tested in Mozambique and Zambia. RESULTS One-hundred percent mortality was reached with all susceptible insectary strains and with wild An. gambiae s.l. from all sites in 11 countries. However, tests in at least one location from 5 countries produced mortality below 98%. While this could potentially be a sign of clothianidin resistance, it is more likely that the diagnostic dose or protocol requires further optimization. Repeat testing in 3 sites in Ghana and Zambia, where possible resistance was detected, subsequently produced 100% mortality. Results showed susceptibility to clothianidin in 38 of the 43 sites in sub-Saharan Africa, including malaria vectors with multiple resistance mechanisms to pyrethroids, carbamates and organophosphates. CONCLUSIONS This study provides an interim diagnostic dose of 2% w/v clothianidin on filter papers which can be utilized by National Malaria Control Programmes and research organizations until the WHO concludes multi-centre studies and provides further guidance.
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Affiliation(s)
- Richard M Oxborough
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA.
| | - Aklilu Seyoum
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Yemane Yihdego
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Roch Dabire
- Institute of Health Science Research, Malaria and Tropical Neglected Research Unit, 01 BP 545, Bobo-Dioulasso, Burkina Faso
| | - Virgile Gnanguenon
- PMI VectorLink Project, Abt Associates, Plot 28 Avenue Pierre Ngendandumwe, Bujumbura, Burundi
| | - Francis Wat'senga
- Entomology Department, National Institute of Biomedical Research, Avenue de la Démocratie, Kinshasa, Democratic Republic of the Congo
| | - Fiacre R Agossa
- PMI VectorLink Project, Abt Associates, Kinshasa, Democratic Republic of the Congo
| | - Gedeon Yohannes
- PMI VectorLink Project, Abt Associates, Gerje Rood Sami Building, Floor 1, Office no 105, P.O. Box : 13646, Addis Ababa, Ethiopia
| | - Sylvester Coleman
- PMI VectorLink Project, Abt Associates, Plot 11 Waterson Road, Fuo, Tamale, Ghana
| | - Lazarus Musa Samdi
- PMI VectorLink Project, Abt Associates, Gte No. 12, TOS Benson Crescent, Utako, Abuja, Nigeria
| | - Abdoulaye Diop
- PMI VectorLink Project, Abt Associates, Immeuble 8639, Sacré-Couer 2, Dakar Fann, PO Box: 25656, Dakar, Senegal
| | - Ousmane Faye
- Université Cheikh Anta Diop, Département de Biologie Animale, Bp 5005 Dakar-Fann, Dakar, Senegal
| | - Stephen Magesa
- PMI VectorLink Project, Abt Associates, PO Box 1212, Mwanza, Tanzania
| | | | - Michael Okia
- PMI VectorLink Project, Abt Associates, Tororo, Uganda
| | - Evelyne Alyko
- PMI VectorLink Project, Abt Associates, Plot No. 3662, Njoka Road, Off Kwacha Road, Box 39090, Olympia, Lusaka, Zambia
| | - Hieronymo Masendu
- PMI VectorLink Project, Abt Associates, 1 Pascoe Avenue, Belgravia, Harare, Zimbabwe
| | - Ibrahima Baber
- PMI VectorLink Project, Abt Associates, Ministry of Gender Compound, Capitol Bye Pass, Monrovia, Liberia
| | - Arthur Sovi
- PMI VectorLink Project, Abt Associates, Cite du Niger 1, Rue 30, Porte 612, Bamako, Mali
| | - Jean-Desire Rakotoson
- PMI VectorLink Project, Abt Associates, Lot Ex La Sice, Ambalanaomby, Farafangana, Madagascar
| | - Kenyssony Varela
- PMI VectorLink Project, Abt Associates, Rua Orlando Mendes, Nº183, Cidade de Maputo, Mozambique
| | - Bernard Abong'o
- PMI VectorLink Project, Abt Associates, White House, Ojijo Oteko Road, Milimani, Kisumu, Kenya
| | - Bradford Lucas
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Christen Fornadel
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, D.C., USA
| | - Dereje Dengela
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
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Oxborough RM, Seyoum A, Yihdego Y, Dabire R, Gnanguenon V, Wat'senga F, Agossa FR, Yohannes G, Coleman S, Samdi LM, Diop A, Faye O, Magesa S, Manjurano A, Okia M, Alyko E, Masendu H, Baber I, Sovi A, Rakotoson JD, Varela K, Abong'o B, Lucas B, Fornadel C, Dengela D. Susceptibility testing of Anopheles malaria vectors with the neonicotinoid insecticide clothianidin; results from 16 African countries, in preparation for indoor residual spraying with new insecticide formulations. Malar J 2019; 18:264. [PMID: 31370898 PMCID: PMC6670198 DOI: 10.1186/s12936-019-2888-6 10.1186/s12936-019-2888-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/22/2019] [Indexed: 10/27/2024] Open
Abstract
BACKGROUND In 2017, more than 5 million house structures were sprayed through the U.S. President's Malaria Initiative, protecting more than 21 million people in sub-Saharan Africa. New IRS formulations, SumiShield™ 50WG and Fludora Fusion™ WP-SB, became World Health Organization (WHO) prequalified vector control products in 2017 and 2018, respectively. Both formulations contain the neonicotinoid active ingredient, clothianidin. The target site of neonicotinoids represents a novel mode of action for vector control, meaning that cross-resistance through existing mechanisms is less likely. In preparation for rollout of clothianidin formulations as part of national IRS rotation strategies, baseline susceptibility testing was conducted in 16 countries in sub-Saharan Africa. METHODS While work coordinated by the WHO is ongoing to develop a suitable bottle bioassay procedure, there was no published guidance regarding clothianidin susceptibility procedures or diagnostic concentrations. Therefore, a protocol was developed for impregnating filter papers with 2% w/v SumiShield™ 50WG dissolved in distilled water. Susceptibility tests were conducted using insectary-reared reference Anopheles and wild collected malaria vector species. All tests were conducted within 24 h of treating papers, with mortality recorded daily for 7 days, due to the slow-acting nature of clothianidin against mosquitoes. Anopheles gambiae sensu lato (s.l.) adults from wild collected larvae were tested in 14 countries, with wild collected F0 Anopheles funestus s.l. tested in Mozambique and Zambia. RESULTS One-hundred percent mortality was reached with all susceptible insectary strains and with wild An. gambiae s.l. from all sites in 11 countries. However, tests in at least one location from 5 countries produced mortality below 98%. While this could potentially be a sign of clothianidin resistance, it is more likely that the diagnostic dose or protocol requires further optimization. Repeat testing in 3 sites in Ghana and Zambia, where possible resistance was detected, subsequently produced 100% mortality. Results showed susceptibility to clothianidin in 38 of the 43 sites in sub-Saharan Africa, including malaria vectors with multiple resistance mechanisms to pyrethroids, carbamates and organophosphates. CONCLUSIONS This study provides an interim diagnostic dose of 2% w/v clothianidin on filter papers which can be utilized by National Malaria Control Programmes and research organizations until the WHO concludes multi-centre studies and provides further guidance.
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Affiliation(s)
- Richard M Oxborough
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA.
| | - Aklilu Seyoum
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Yemane Yihdego
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Roch Dabire
- Institute of Health Science Research, Malaria and Tropical Neglected Research Unit, 01 BP 545, Bobo-Dioulasso, Burkina Faso
| | - Virgile Gnanguenon
- PMI VectorLink Project, Abt Associates, Plot 28 Avenue Pierre Ngendandumwe, Bujumbura, Burundi
| | - Francis Wat'senga
- Entomology Department, National Institute of Biomedical Research, Avenue de la Démocratie, Kinshasa, Democratic Republic of the Congo
| | - Fiacre R Agossa
- PMI VectorLink Project, Abt Associates, Kinshasa, Democratic Republic of the Congo
| | - Gedeon Yohannes
- PMI VectorLink Project, Abt Associates, Gerje Rood Sami Building, Floor 1, Office no 105, P.O. Box : 13646, Addis Ababa, Ethiopia
| | - Sylvester Coleman
- PMI VectorLink Project, Abt Associates, Plot 11 Waterson Road, Fuo, Tamale, Ghana
| | - Lazarus Musa Samdi
- PMI VectorLink Project, Abt Associates, Gte No. 12, TOS Benson Crescent, Utako, Abuja, Nigeria
| | - Abdoulaye Diop
- PMI VectorLink Project, Abt Associates, Immeuble 8639, Sacré-Couer 2, Dakar Fann, PO Box: 25656, Dakar, Senegal
| | - Ousmane Faye
- Université Cheikh Anta Diop, Département de Biologie Animale, Bp 5005 Dakar-Fann, Dakar, Senegal
| | - Stephen Magesa
- PMI VectorLink Project, Abt Associates, PO Box 1212, Mwanza, Tanzania
| | | | - Michael Okia
- PMI VectorLink Project, Abt Associates, Tororo, Uganda
| | - Evelyne Alyko
- PMI VectorLink Project, Abt Associates, Plot No. 3662, Njoka Road, Off Kwacha Road, Box 39090, Olympia, Lusaka, Zambia
| | - Hieronymo Masendu
- PMI VectorLink Project, Abt Associates, 1 Pascoe Avenue, Belgravia, Harare, Zimbabwe
| | - Ibrahima Baber
- PMI VectorLink Project, Abt Associates, Ministry of Gender Compound, Capitol Bye Pass, Monrovia, Liberia
| | - Arthur Sovi
- PMI VectorLink Project, Abt Associates, Cite du Niger 1, Rue 30, Porte 612, Bamako, Mali
| | - Jean-Desire Rakotoson
- PMI VectorLink Project, Abt Associates, Lot Ex La Sice, Ambalanaomby, Farafangana, Madagascar
| | - Kenyssony Varela
- PMI VectorLink Project, Abt Associates, Rua Orlando Mendes, Nº183, Cidade de Maputo, Mozambique
| | - Bernard Abong'o
- PMI VectorLink Project, Abt Associates, White House, Ojijo Oteko Road, Milimani, Kisumu, Kenya
| | - Bradford Lucas
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Christen Fornadel
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, D.C., USA
| | - Dereje Dengela
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
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Lees R, Praulins G, Davies R, Brown F, Parsons G, White A, Ranson H, Small G, Malone D. A testing cascade to identify repurposed insecticides for next-generation vector control tools: screening a panel of chemistries with novel modes of action against a malaria vector. Gates Open Res 2019; 3:1464. [PMID: 31259317 PMCID: PMC6556762 DOI: 10.12688/gatesopenres.12957.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2019] [Indexed: 08/31/2023] Open
Abstract
Background: With insecticide resistance in malaria vectors spreading in geographical range and intensity, there is a need for compounds with novel modes of action to maintain the successes achieved to date by long-lasting insecticidal nets and indoor residual sprays, used as part of an insecticide resistance management strategy. Screening existing registered pesticides, predominantly those developed for use in agriculture, may provide a more rapid and less logistically challenging route to identifying active ingredients of value to public health than screening and chemical synthesis programmes for novel compounds. Methods: Insecticides and acaricides from all IRAC classes, including those with unclassified modes of action, were assessed for inclusion in a laboratory bioassay testing cascade against adult female Anopheles gambiae mosquitoes. A longlist of representative candidate compounds was selected, excluding those with safety concerns, unsuitable physiochemical properties, and likely hurdles to registration for public health use. An initial screen using topical application eliminated compounds with insufficient intrinsic activity, and a tarsal contact assay identified those with activity at an appropriate concentration. Compounds of interest were ranked by relative potency using dose response assays and discriminating dose calculations. Results: Inclusion of an adjuvant enhanced the tarsal efficacy of several compounds, facilitating the promotion of chemistries with great potential, given suitable formulation, which would not progress based on activity of compound alone. Comparison of data between stages in the testing cascade suggest that a more streamlined approach, topical application to test for intrinsic activity and determining the discriminating dose to compare relative potency of compounds, may be sufficient to identify compounds with potential value for use in long lasting insecticidal nets and indoor residual spray products. Conclusions: Identified were 11 compounds of interest as vector control agents (in descending order of potency): clothianidin, spinetoram, metaflumizone, dinotefuran, indoxacarb, abamectin, sulfoxaflor, oxazosulfyl, triflumezopyrim, fenpyroximate, and tolfenpyrad.
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Affiliation(s)
- Rosemary Lees
- Liverpool Insect Testing Establishment (LITE), Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Giorgio Praulins
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Rachel Davies
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Faye Brown
- Liverpool Insect Testing Establishment (LITE), Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - George Parsons
- Liverpool Insect Testing Establishment (LITE), Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Anthony White
- Innovative Vector Control Consortium (IVCC), Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
| | - Hilary Ranson
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Graham Small
- Innovative Vector Control Consortium (IVCC), Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
| | - David Malone
- Innovative Vector Control Consortium (IVCC), Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
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Lees R, Praulins G, Davies R, Brown F, Parsons G, White A, Ranson H, Small G, Malone D. A testing cascade to identify repurposed insecticides for next-generation vector control tools: screening a panel of chemistries with novel modes of action against a malaria vector. Gates Open Res 2019; 3:1464. [PMID: 31259317 PMCID: PMC6556762 DOI: 10.12688/gatesopenres.12957.2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2019] [Indexed: 11/27/2022] Open
Abstract
Background: With insecticide resistance in malaria vectors spreading in geographical range and intensity, there is a need for compounds with novel modes of action to maintain the successes achieved to date by long-lasting insecticidal nets and indoor residual sprays, used as part of an insecticide resistance management strategy. Screening existing registered pesticides, predominantly those developed for use in agriculture, may provide a more rapid and less logistically challenging route to identifying active ingredients of value to public health than screening and chemical synthesis programmes for novel compounds. Methods: Insecticides and acaricides from all IRAC classes, including those with unclassified modes of action, were assessed for inclusion in a laboratory bioassay testing cascade against adult female
Anopheles gambiae mosquitoes. A longlist of representative candidate compounds was selected, excluding those with safety concerns, unsuitable physiochemical properties, and likely hurdles to registration for public health use. An initial screen using topical application eliminated compounds with insufficient intrinsic activity, and a tarsal contact assay identified those with activity at an appropriate concentration. Compounds of interest were ranked by relative potency using dose response assays and discriminating dose calculations. Results: Inclusion of an adjuvant enhanced the tarsal efficacy of several compounds, facilitating the promotion of chemistries with great potential, given suitable formulation, which would not progress based on activity of compound alone. Comparison of data between stages in the testing cascade suggest that a more streamlined approach, topical application to test for intrinsic activity and determining the discriminating dose to compare relative potency of compounds, may be sufficient to identify compounds with potential value for use in long lasting insecticidal nets and indoor residual spray products. Conclusions: Identified were 11 compounds of interest as vector control agents (in descending order of potency): clothianidin, spinetoram, metaflumizone, dinotefuran, indoxacarb, abamectin, sulfoxaflor, oxazosulfyl, triflumezopyrim, fenpyroximate, and tolfenpyrad.
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Affiliation(s)
- Rosemary Lees
- Liverpool Insect Testing Establishment (LITE), Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.,Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Giorgio Praulins
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Rachel Davies
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Faye Brown
- Liverpool Insect Testing Establishment (LITE), Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - George Parsons
- Liverpool Insect Testing Establishment (LITE), Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Anthony White
- Innovative Vector Control Consortium (IVCC), Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
| | - Hilary Ranson
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Graham Small
- Innovative Vector Control Consortium (IVCC), Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
| | - David Malone
- Innovative Vector Control Consortium (IVCC), Liverpool School of Tropical Medicine, Liverpool, Merseyside, L3 5QA, UK
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Ngwej LM, Hattingh I, Mlambo G, Mashat EM, Kashala JCK, Malonga FK, Bangs MJ. Indoor residual spray bio-efficacy and residual activity of a clothianidin-based formulation (SumiShield ® 50WG) provides long persistence on various wall surfaces for malaria control in the Democratic Republic of the Congo. Malar J 2019; 18:72. [PMID: 30866934 PMCID: PMC6417189 DOI: 10.1186/s12936-019-2710-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/06/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bio-efficacy and residual activity of SumiShield® 50WG (50%, w/w) with active ingredient clothianidin, a neonicotinoid compound, was assessed using an insecticide-susceptible laboratory strain of Anopheles arabiensis. Implications of the findings are examined in the context of potential alternative insecticides for indoor residual spraying in Lualaba Province, Democratic Republic of the Congo. METHODS Contact surface bioassays were conducted for 48 weeks on four types of walls (unbaked clay, baked clay, cement, painted cement) in simulated semi-field experimental conditions using two different doses of clothianidin active ingredient (200 mg ai/sq m and 300 mg ai/sq m). Additionally, two types of walls (painted cement and baked clay) were examined in occupied houses using the 300-mg dosage. Laboratory-reared An. arabiensis were exposed to treated surfaces or untreated (controls) for 30 min. Mortality was recorded at 24-h intervals for 120 h. RESULTS Under semi-field experimental conditions, there was no significant difference in mortality over time between the two doses of clothianidin. The mortality rates remained above 60% up to 48 weeks on all four wall surface types. The formulation performed better on cement and unbaked clay with a mean final mortality rate above 90%. Under natural conditions, there was no significant difference in response between baked clay and painted cement walls with a mean final mortality rate above 90%. The insecticide also performed significantly better in natural settings compared to semi-field experimental conditions. CONCLUSION Depending on the type of experimental surface, the residual activity of the two doses of clothianidin was between 28 and 48 weeks based on a 60% mortality endpoint. Clothianidin at 300 mg ai/sq m applied on two house walls (baked clay or painted cement) performed equally well (> 80% mortality) on both surfaces up to week 41 (approximately 9.5 months). Extended bioassay holding periods (up to 120 h) may present with excess natural mortality in the untreated controls, thus complicating analysis.
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Affiliation(s)
- Leonard M Ngwej
- China Molybdenum Co., Ltd./International SOS Malaria Control Programme, Tenke Fungurume Mining, Fungurume, Lualaba Province, Democratic Republic of the Congo.
- School of Public Health, University of Lubumbashi, Lubumbashi, Democratic Republic of the Congo.
| | - Izak Hattingh
- China Molybdenum Co., Ltd./International SOS Malaria Control Programme, Tenke Fungurume Mining, Fungurume, Lualaba Province, Democratic Republic of the Congo
| | - Godwill Mlambo
- China Molybdenum Co., Ltd./International SOS Malaria Control Programme, Tenke Fungurume Mining, Fungurume, Lualaba Province, Democratic Republic of the Congo
| | - Emmanuel M Mashat
- China Molybdenum Co., Ltd./International SOS Malaria Control Programme, Tenke Fungurume Mining, Fungurume, Lualaba Province, Democratic Republic of the Congo
| | - Jean-Christophe K Kashala
- Faculty of Veterinary Medicine, University of Lubumbashi, Lubumbashi, Democratic Republic of the Congo
| | - Françoise K Malonga
- School of Public Health, University of Lubumbashi, Lubumbashi, Democratic Republic of the Congo
| | - Michael J Bangs
- China Molybdenum Co., Ltd./International SOS Malaria Control Programme, Tenke Fungurume Mining, Fungurume, Lualaba Province, Democratic Republic of the Congo
- Public Health & Malaria Control Department, PT Freeport Indonesia, International SOS, Jl. Kertajasa, Kuala Kencana, Papua, 99920, Indonesia
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, 10900, Thailand
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Kweka E, Mahande A, Ouma J, Karanja W, Msangi S, Temba V, Lyaruu L, Himeidan Y. Novel Indoor Residual Spray Insecticide With Extended Mortality Effect: A Case of SumiShield 50WG Against Wild Resistant Populations of Anopheles arabiensis in Northern Tanzania. GLOBAL HEALTH: SCIENCE AND PRACTICE 2018; 6:758-765. [PMID: 30591581 PMCID: PMC6370354 DOI: 10.9745/ghsp-d-18-00213] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 11/13/2018] [Indexed: 12/14/2022]
Abstract
The new SumiShield 50WG insecticide, which possibly has longer duration of effectiveness than other indoor residual spray (IRS) formulations, has potential as an alternative IRS product for malaria vector control, particularly where resistance to other formulations has developed. Background: Resistance of malaria vectors to different classes of insecticides has been reported in malaria-endemic areas. Identifying new indoor residual spray (IRS) compounds that are effective against resistant vector populations is a high priority in managing insecticide resistance. Method: A biological efficacy trial was conducted in the field from August 2016 to February 2017 to determine the efficacy of SumiShield 50WG, a new insecticide class, against wild Anopheles arabiensis. Indoor surfaces of 20 houses in Mabogini ward in the rural district of Moshi in northern Tanzania were sprayed with SumiShield 50WG. Bio-efficacy monitoring was conducted monthly for 6 months after the spray application. In addition, susceptibility tests were conducted by exposing mosquitoes to papers treated with permethrin 0.75%, pirimiphos-methyl 0.25%, and clothianidin 2% (SumiShield 50WG). Representatives from each household included in the study were surveyed about possible side effects or problems faced since the spray. Regression probit analysis was used to calculate knock-down times while the chi-square test was used to compare the mortality effect for mosquitoes. Results: The SumiShield 50WG insecticide maintained optimal efficacy in the field setting for the duration of the 6-month study period, with 100% mortality of mosquitoes by 144 to 168 hours post-exposure to treated surfaces. Susceptibility tests showed some variation in tolerance to the tested insecticide-treated papers, particularly between SumiShield 50WG and pirimiphos-methyl. The knock-down times for 50% and 95% of the mosquitoes when exposed to SumiShield 50WG-treated test paper were 45.81 minutes and 83.85 minutes, respectively, and 67.77 minutes and 105.81 minutes, respectively, for the pirimiphos-methyl-treated papers. There were no short-term adverse side effects reported by households sprayed with SumiShield 50WG. Conclusion: The findings of this study suggest that SumiShield 50WG is a viable IRS insecticide for malaria vector control in Tanzania, especially in areas where pyrethroid resistance is a concern.
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Affiliation(s)
- Eliningaya Kweka
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, Mwanza, Tanzania. .,Mosquito Section, Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, Arusha, Tanzania
| | - Aneth Mahande
- Mabogini field station, Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, Moshi, Tanzania
| | - Johnson Ouma
- Africa Technical Research Centre, Vector Health International Ltd., Arusha, Tanzania
| | - Wycliffe Karanja
- Africa Technical Research Centre, Vector Health International Ltd., Arusha, Tanzania
| | - Shandala Msangi
- Mosquito Section, Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, Arusha, Tanzania
| | - Violet Temba
- Mosquito Section, Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, Arusha, Tanzania
| | - Lucille Lyaruu
- Mosquito Section, Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, Arusha, Tanzania
| | - Yousif Himeidan
- Africa Technical Research Centre, Vector Health International Ltd., Arusha, Tanzania
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Deshayes C, Moreau E, Pitti-Caballero J, Froger JA, Apaire-Marchais V, Lapied B. Synergistic agent and intracellular calcium, a successful partnership in the optimization of insecticide efficacy. CURRENT OPINION IN INSECT SCIENCE 2018; 30:52-58. [PMID: 30553485 DOI: 10.1016/j.cois.2018.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 06/09/2023]
Abstract
Integrated Pest Management and Integrated Vector Management worldwide are developed in agriculture and public health to counteract and limit the exponential increasing development of insect resistance to insecticides. However, facing the predominance of some resistant populations, new strategies are urgently needed to target resistant insects. An innovative approach lies in the optimization of commonly used insecticides when combined with chemical or biological synergistic agents. By an increase of intracellular calcium concentration followed by activation of calcium-dependant signalling pathways, the synergistic agents are able to indirectly increase target sites sensitivity to insecticide by inducing conformational change. The synergistic agents are of great interest in optimizing the efficacy of insecticides and in overcoming resistance mechanisms.
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Affiliation(s)
- Caroline Deshayes
- Laboratoire Signalisation Fonctionnelle des Canaux Ioniques et Récepteurs (SiFCIR), UPRES-EA 2647, USC INRA 1330, SFR 4207 QUASAV, UFR Sciences, Université d'Angers, 2 Boulevard Lavoisier, F-49045 Angers Cedex, France
| | - Eléonore Moreau
- Laboratoire Signalisation Fonctionnelle des Canaux Ioniques et Récepteurs (SiFCIR), UPRES-EA 2647, USC INRA 1330, SFR 4207 QUASAV, UFR Sciences, Université d'Angers, 2 Boulevard Lavoisier, F-49045 Angers Cedex, France
| | - Javier Pitti-Caballero
- Laboratoire Signalisation Fonctionnelle des Canaux Ioniques et Récepteurs (SiFCIR), UPRES-EA 2647, USC INRA 1330, SFR 4207 QUASAV, UFR Sciences, Université d'Angers, 2 Boulevard Lavoisier, F-49045 Angers Cedex, France
| | - Josy-Anne Froger
- Laboratoire Signalisation Fonctionnelle des Canaux Ioniques et Récepteurs (SiFCIR), UPRES-EA 2647, USC INRA 1330, SFR 4207 QUASAV, UFR Sciences, Université d'Angers, 2 Boulevard Lavoisier, F-49045 Angers Cedex, France
| | - Véronique Apaire-Marchais
- Laboratoire Signalisation Fonctionnelle des Canaux Ioniques et Récepteurs (SiFCIR), UPRES-EA 2647, USC INRA 1330, SFR 4207 QUASAV, UFR Sciences, Université d'Angers, 2 Boulevard Lavoisier, F-49045 Angers Cedex, France
| | - Bruno Lapied
- Laboratoire Signalisation Fonctionnelle des Canaux Ioniques et Récepteurs (SiFCIR), UPRES-EA 2647, USC INRA 1330, SFR 4207 QUASAV, UFR Sciences, Université d'Angers, 2 Boulevard Lavoisier, F-49045 Angers Cedex, France.
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Systematic review of indoor residual spray efficacy and effectiveness against Plasmodium falciparum in Africa. Nat Commun 2018; 9:4982. [PMID: 30478327 PMCID: PMC6255894 DOI: 10.1038/s41467-018-07357-w] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 10/25/2018] [Indexed: 11/08/2022] Open
Abstract
Indoor residual spraying (IRS) is an important part of malaria control. There is a growing list of insecticide classes; pyrethroids remain the principal insecticide used in bednets but recently, novel non-pyrethroid IRS products, with contrasting impacts, have been introduced. There is an urgent need to better assess product efficacy to help decision makers choose effective and relevant tools for mosquito control. Here we use experimental hut trial data to characterise the entomological efficacy of widely-used, novel IRS insecticides. We quantify their impact against pyrethroid-resistant mosquitoes and use a Plasmodium falciparum transmission model to predict the public health impact of different IRS insecticides. We report that long-lasting IRS formulations substantially reduce malaria, though their benefit over cheaper, shorter-lived formulations depends on local factors including bednet use, seasonality, endemicity and pyrethroid resistance status of local mosquito populations. We provide a framework to help decision makers evaluate IRS product effectiveness.
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