Efficacy of chlorfenapyr and pyriproxyfen in the control of arbovirus vectors in Benin

Background Insecticide resistance in the vectors population remains a major challenge to the effective control of arboviral diseases. In the current context where Aedes vectors have developed resistance to pyrethroids, it is essential to explore alternative insecticidal compounds. This study aimed to assess the resistance profiles of the main arbovirus vectors to next-generation insecticides, specifically Chlorfenapyr and Pyriproxyfen. Methods The study was conducted in four municipalities in southern Benin. Vectors were collected using ovitraps and reared to the adult stage. Aedes aegypti and Aedes albopictus populations were used directly for the various tests. CDC bottle bioassays were performed to evaluate vector susceptibility to Chlorfenapyr and to assess the reproductive inhibition properties of Pyriproxyfen. Cone and tunnel tests were conducted to determine the bioefficacy of Royal Guard ® and Interceptor ® G2 long-lasting insecticidal nets (LLINs). Results Results revealed full susceptibility of both Aedes aegypti and Aedes albopictus to Chlorfenapyr, with mortality rates ranging from 98% to 100% across all municipalities. Pyriproxyfen significantly reduced oviposition in Aedes aegypti, with inhibition rates ranging from 91.7 % to 99% across all study sites. Similar outcomes were observed in Aedes albopictus, with oviposition rates ranging from 0% (0–3.6) to 6.1% (2.3–12.9). Blood-feeding and penetration rates for both species exposed to Interceptor® G2 were low, while mortality rates remained high. Both types of LLINs demonstrated optimal efficacy against the susceptible Aedes aegypti strain (Rockefeller). Conclusion The study demonstrated the effectiveness of Chlorfenapyr and Pyriproxyfen as promising alternatives for managing pyrethroid-resistant Aedes populations. The LLINs impregnated with these compounds Royal Guard® (alpha-cypermethrin + Pyriproxyfen) and Interceptor® G2 (alpha-cypermethrin + Chlorfenapyr) also proved effective against wild Aedes populations and could serve as valuable tools in arbovirus vector control strategies.