Recent reductions in malaria transmission in Africa are predominantly due to massive use of bednets impregnated with an insecticide chemical called ‘’pyrethroid’’. unfortunately, resistance to this product is threatening the efficacy of long-lasting insecticidal nets (LLINs). To mitigate this risk, novel insecticides such as chlorfenapyr are recommended by WHO to kill these malaria-transmitting mosquitoes. In this study, we assessed the susceptibility status of the major malaria vectors Anopheles gambiae and Anopheles funestus to chlorfenapyr across Africa and check if mechanisms behind resistance to pyrethroid can also confer resistance to this new insecticide. The efficacy of chlorfenapyr insecticide was evaluated on mosquitoes collected from five Cameroonian locations, the Democratic Republic of Congo, Ghana, and Uganda.
We noticed that this product is killing all the Anopheles funestus but only few Anopheles gambiae in DRC (Kinshasa) (mortality rate: 64.3 ± 7.1%), Ghana (Obuasi) (65.9 ± 7.4%), and Cameroon (Mangoum ;75.2±7.7% and Nkolondom ; 86.1 ± 7.4). We observed that molecular mechanisms helping mosquitoes to survive when exposed to pyrethroid are not conferring resistance to chlorfenapyr, indicating that chlorfenapyr resistance needs to be well monitored and mechanisms driving resistance to this new insecticide class elucidated to help prolong the effectiveness of chlorfenapyr-based tools such as the new LLIN interceptor G2®.
Read more :Tchouakui, M., Assatse, T., Tazokong, H.R. et al. Detection of a reduced susceptibility to chlorfenapyr in the malaria vector Anopheles gambiae contrasts with full susceptibility in Anopheles funestus across Africa. Sci Rep13, 2363 (2023). https://doi.org/10.1038/s41598-023-29605-w
