Determination of the discriminating concentration of chlorfenapyr (pyrrole) and Anopheles gambiae sensu lato susceptibility testing in preparation for distribution of Interceptor® G2 insecticide-treated nets

Malaria Journal

Ousmane Faye¹  Francis Wat’senga²  Roch Dabire³  Hieronymo Masendu⁴  Ibrahima Baber⁵  Dereje Dengela⁶  Yemane Yihdego⁶  Aklilu Seyoum⁶  Joseph Chabi⁶  Richard M. Oxborough⁶  Mohamed Bayoh⁷  Evelyne Alyko⁸  Libasse Gadiaga⁹  Arthur Sovi^1,10  Samdi Lazarus Musa^1,11  Fiacre R. Agossa^1,12  Jean-Desire Rakotoson^1,13  Etienne Fondjo^1,14  Bernard Abong’o^1,15  Kevin Opondo^1,15  Gedeon Yohannes^1,16  Sylvester Coleman^1,17  Virgile Gnanguenon^1,18  Kenyssony Varela^1,19  Michael Okia^2,20  Jenny Carlson^2,21  Jennifer S. Armistead^2,21 

[1] Département de Biologie Animale, Université Cheikh Anta Diop, Bp 5005 Dakar-Fann, Dakar, Senegal;Entomology Department, National Institute of Biomedical Research, Avenue de la Démocratie, Kinshasa, Democratic Republic of the Congo;Institute of Health Science Research, Malaria and Tropical Neglected Research Unit, 01 BP 545, Bobo-Dioulasso, Burkina Faso;PMI VectorLink Project, Abt Associates, 1 Pascoe Avenue, Belgravia, Harare, Zimbabwe;PMI VectorLink Project, Abt Associates, 16th Street, Beach Side, Sinkor, Monrovia, Liberia;PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, 20852, Rockville, MD, USA;PMI VectorLink Project, Abt Associates, Box 39090, Njoka Road, Off Kwacha Road, Olympia, Lusaka, Zambia;PMI VectorLink Project, Abt Associates, Box 39090, Njoka Road, Off Kwacha Road, Olympia, Lusaka, Zambia;PMI VectorLink Project, Abt Associates, Freetown, Sierra Leone;PMI VectorLink Project, Abt Associates, Cite du Niger 1, Rue 30, Porte 612, Bamako, Mali;PMI VectorLink Project, Abt Associates, Cite du Niger 1, Rue 30, Porte 612, Bamako, Mali;Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, WC1E 7HT, London, UK;Faculty of Agronomy, University of Parakou, BP 123, Parakou, Benin;PMI VectorLink Project, Abt Associates, Gte No. 12 TOS Benson Crescent, Utako, Abuja, Nigeria;PMI VectorLink Project, Abt Associates, Kinshasa, Democratic Republic of the Congo;PMI VectorLink Project, Abt Associates, Lot Ex La Sice, Ambalanaomby, Farafangana, Madagascar;PMI VectorLink Project, Abt Associates, P.O. Box 14 025, P.O. Box 14 025, Mballa II, Dragages, Yaounde, Cameroon;PMI VectorLink Project, Abt Associates, P.O. Box 895-40123, Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, Kisumu, Milimani, Kenya;PMI VectorLink Project, Abt Associates, P.O. Box : 13646, Gerje Rood Sami Building, Floor 1, Office no 105, Addis Ababa, Ethiopia;PMI VectorLink Project, Abt Associates, Plot 11 Waterson Road, Fuo, Tamale, Ghana;PMI VectorLink Project, Abt Associates, Plot 28 Avenue Pierre Ngendandumwe, Bujumbura, Burundi;PMI VectorLink Project, Abt Associates, Rua Justino Chemane, No. 237 Sommerschield 2, Maputo, Mozambique;PMI VectorLink Project, Abt Associates, Tororo, Uganda;U.S. President’s Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA;

关键词: Chlorfenapyr;    Pyrrole;    Anopheles gambiae;    Interceptor G2;    CDC bottle bioassay;    Discriminating concentration;    Insecticide-treated net;    Insecticide resistance;   

DOI  :  10.1186/s12936-021-03847-3

来源: Springer

【 摘 要 】

BackgroundFollowing agricultural use and large-scale distribution of insecticide-treated nets (ITNs), malaria vector resistance to pyrethroids is widespread in sub-Saharan Africa. Interceptor® G2 is a new dual active ingredient (AI) ITN treated with alpha-cypermethrin and chlorfenapyr for the control of pyrethroid-resistant malaria vectors. In anticipation of these new nets being more widely distributed, testing was conducted to develop a chlorfenapyr susceptibility bioassay protocol and gather susceptibility information.MethodsBottle bioassay tests were conducted using five concentrations of chlorfenapyr at 12.5, 25, 50, 100, and 200 µg AI/bottle in 10 countries in sub-Saharan Africa using 13,639 wild-collected Anopheles gambiae sensu lato (s.l.) (56 vector populations per dose) and 4,494 pyrethroid-susceptible insectary mosquitoes from 8 colonized strains. In parallel, susceptibility tests were conducted using a provisional discriminating concentration of 100 µg AI/bottle in 16 countries using 23,422 wild-collected, pyrethroid-resistant An. gambiae s.l. (259 vector populations). Exposure time was 60 min, with mortality recorded at 24, 48 and 72 h after exposure.ResultsMedian mortality rates (up to 72 h after exposure) of insectary colony mosquitoes was 100% at all five concentrations tested, but the lowest dose to kill all mosquitoes tested was 50 µg AI/bottle. The median 72-h mortality of wild An. gambiae s.l. in 10 countries was 71.5, 90.5, 96.5, 100, and 100% at concentrations of 12.5, 25, 50, 100, and 200 µg AI/bottle, respectively. Log-probit analysis of the five concentrations tested determined that the LC95 of wild An. gambiae s.l. was 67.9 µg AI/bottle (95% CI: 48.8–119.5). The discriminating concentration of 203.8 µg AI/bottle (95% CI: 146–359) was calculated by multiplying the LC95 by three. However, the difference in mortality between 100 and 200 µg AI/bottle was minimal and large-scale testing using 100 µg AI/bottle with wild An. gambiae s.l. in 16 countries showed that this concentration was generally suitable, with a median mortality rate of 100% at 72 h.ConclusionsThis study determined that 100 or 200 µg AI/bottle chlorfenapyr in bottle bioassays are suitable discriminating concentrations for monitoring susceptibility of wild An. gambiae s.l., using mortality recorded up to 72 h. Testing in 16 countries in sub-Saharan Africa demonstrated vector susceptibility to chlorfenapyr, including mosquitoes with multiple resistance mechanisms to pyrethroids.

【 授权许可】

CC BY