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

Célestine Atyame Nten (1, 2) , Haoues Alout (3, 4) , Laurence Mousson (2) , Marie Vazeille (2) , Mawlouth Diallo (5) , Mylène Weill (3) , Anna-Bella Failloux (2)

1 PIMIT - Processus Infectieux en Milieu Insulaire Tropical
2 Arbovirus et Insectes Vecteurs - Arboviruses and Insect Vectors
3 UMR ISEM - Institut des Sciences de l'Evolution de Montpellier
4 UMR ASTRE - Animal, Santé, Territoires, Risques et Ecosystèmes
5 Institut Pasteur de Dakar

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. quin-quefasciatus 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.

Keywords: arboviruses; vector competence; microbiology Keywords: insecticide resistance; genetics; Subject Category: Ecology Subject Areas: ecology; Culex quinquefasciatus; insecticide resistance

Domains: Life Sciences [q-bio]; Microbiology and Parasitology; Virology

Célestine Atyame Nten, Haoues Alout, Laurence Mousson, Marie Vazeille, Mawlouth Diallo, et al.. Insecticide resistance genes affect Culex quinquefasciatus vector competence for West Nile virus. Proceedings of the Royal Society B: Biological Sciences, 2019, 286 (1894), pp.20182273. ⟨10.1098/rspb.2018.2273⟩. ⟨pasteur-02098394⟩