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Kibondo UA, Odufuwa OG, Ngonyani SH, Mpelepele AB, Matanilla I, Ngonyani H, Makungwa NO, Mseka AP, Swai K, Ntabaliba W, Stutz S, Austin JW, Moore SJ. Influence of testing modality on bioefficacy for the evaluation of Interceptor ® G2 mosquito nets to combat malaria mosquitoes in Tanzania. Parasit Vectors 2022; 15:124. [PMID: 35410250 PMCID: PMC8996609 DOI: 10.1186/s13071-022-05207-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 02/15/2022] [Indexed: 12/02/2022] Open
Abstract
Background Insecticide-treated net (ITN) durability is evaluated using longitudinal bioefficacy and fabric integrity sampling post-distribution. Interceptor® G2 was developed for resistance management and contains two adulticides: alpha-cypermethrin and chlorfenapyr; it is a pro-insecticide that is metabolized into its active form by mosquito-detoxifying enzymes and may be enhanced when the mosquito is physiologically active. To elucidate the impact of bioassay modality, mosquito exposures of the alphacypermethrin ITN Interceptor® and dual adulticide Interceptor® G2 were investigated. Methods This study evaluated the performance of Interceptor® G2 compared to Interceptor® against local strains of mosquitoes in Tanzania. Unwashed and 20× times washed nets were tested. Efficacy of ITNs was measured by four bioassay types: (1) World Health Organisation (WHO) cone test (cone), (2) WHO tunnel test (tunnel), (3) Ifakara ambient chamber test (I-ACT) and (4) the WHO gold standard experimental hut test (hut). Hut tests were conducted against free-flying wild pyrethroid metabolically resistant Anopheles arabiensis and Culex quinquefasciatus. Cone, tunnel and I-ACT bioassays used laboratory-reared metabolically resistant An. arabiensis and Cx. quinquefasciatus and pyrethroid susceptible Anopheles gambiae sensu stricto and Aedes aegypti. Results Against resistant strains, superiority of Interceptor® G2 over Interceptor® was observed in all “free-flying bioassays”. In cone tests (which restrict mosquito flight), superiority of Interceptor® over Interceptor® G2 was recorded. Mortality of unwashed Interceptor® G2 among An. arabiensis was lowest in hut tests at 42.9% (95% CI: 37.3–48.5), although this increased to 66.7% (95% CI: 47.1–86.3) by blocking hut exit traps so mosquitoes presumably increased frequencies of contact with ITNs. Higher odds of mortality were consistently observed in Interceptor® G2 compared to Interceptor® in “free-flying” bioassays using An. arabiensis: tunnel (OR = 1.42 [95% CI:1.19–1.70], p < 0.001), I-ACT (OR = 1.61 [95% CI: 1.05–2.49], p = 0.031) and hut (OR = 2.53 [95% CI: 1.96–3.26], p < 0.001). Interceptor® and Interceptor® G2 showed high blood-feeding inhibition against all strains. Conclusion Both free-flying laboratory bioassays (WHO Tunnel and I-ACT) consistently measured similarly, and both predicted the results of the experimental hut test. For bioefficacy monitoring and upstream product evaluation of ITNs in situ, the I-ACT may provide an alternative bioassay modality with improved statistical power. Interceptor G2® outperformed Interceptor ® against pyrethroid-resistant strains, demonstrating the usefulness of chlorfenapyr in mitigation of malaria. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05207-9.
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Affiliation(s)
- Ummi Abdul Kibondo
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania.
| | - Olukayode G Odufuwa
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania.,Vector Biology Unit, Department of Epidemiology and Public Health, Swiss Tropical & Public Health Institute, Kreuzstrasse 2, 4123, Allschwil, Switzerland.,MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, England
| | - Saphina H Ngonyani
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | - Ahmadi B Mpelepele
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | - Issaya Matanilla
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | - Hassan Ngonyani
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | - Noel O Makungwa
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | - Antony P Mseka
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | - Kyeba Swai
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania.,Vector Biology Unit, Department of Epidemiology and Public Health, Swiss Tropical & Public Health Institute, Kreuzstrasse 2, 4123, Allschwil, Switzerland
| | - Watson Ntabaliba
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | - Susanne Stutz
- Professional & Specialty Solutions, BASF SE, Public Health, 67117, Limburgerhof, Germany
| | - James W Austin
- Professional & Specialty Solutions, BASF Corporation, Public Health Global Development, Research Triangle Park, NC, 27709, USA
| | - Sarah Jane Moore
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania.,Vector Biology Unit, Department of Epidemiology and Public Health, Swiss Tropical & Public Health Institute, Kreuzstrasse 2, 4123, Allschwil, Switzerland.,University of Basel, Petersplatz 1, 4001, Basel, Switzerland.,Nelson Mandela African Institute of Science and Technology (NM-AIST), P.O. Box 447, Tengeru, Tanzania
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