Insecticide resistance genes affect Culex quinquefasciatus vector competence for West Nile virus

• Published in: Proceedings of the Royal Society. B, Biological sciences Vol. 286; no. 1894; p. 20182273
• Main Authors: Atyame, Célestine M., Alout, Haoues, Mousson, Laurence, Vazeille, Marie, Diallo, Mawlouth, Weill, Mylène, Failloux, Anna-Bella
• Format: Journal Article
• Language: English
• Published: England Royal Society, The 16.01.2019; The Royal Society
• Subjects: Animals; Culex - drug effects; Culex - genetics; Culex - virology; Ecology; Feeding Behavior; Female; Genes, Insect; Insecticide Resistance - genetics; Life Sciences; Microbiology and Parasitology; Mosquito Vectors - drug effects; Mosquito Vectors - genetics; Mosquito Vectors - virology; Virology; West Nile Fever - transmission; West Nile virus - physiology; vector competence; insecticide resistance; arboviruses; Culex quinquefasciatus; genetics; microbiology Keywords: insecticide resistance; Subject Category: Ecology Subject Areas: ecology
• ISSN: 0962-8452; 1471-2954; 1471-2954
• DOI: 10.1098/rspb.2018.2273

Insecticide resistance has been reported to impact the interactions between mosquitoes and the pathogens they transmit. However, the effect on vector competence for arboviruses still remained to be investigated. We examined the influence of two insecticide resistance mechanisms on vector competence of the mosquito Culex quinquefasciatus for two arboviruses, Rift Valley Fever virus (RVFV) and West Nile virus (WNV). Three Cx. quinquefasciatus lines sharing a common genetic background were used: two insecticide-resistant lines, one homozygous for amplification of the Ester 2 locus (SA2), the other homozygous for the acetylcholinesterase ace-1 G119S mutation (SR) and the insecticide-susceptible reference line Slab. Statistical analyses revealed no significant effect of insecticide-resistant mechanisms on vector competence for RVFV. However, both insecticide resistance mechanisms significantly influenced the outcome of WNV infections by increasing the dissemination of WNV in the mosquito body, therefore leading to an increase in transmission efficiency by resistant mosquitoes. These results showed that insecticide resistance mechanisms enhanced vector competence for WNV and may have a significant impact on transmission dynamics of arboviruses. Our findings highlight the importance of understanding the impacts of insecticide resistance on the vectorial capacity parameters to assess the overall consequence on transmission.