Vector competence of Aedes vexans (Meigen), Culex poicilipes (Theobald) and Cx. quinquefasciatus Say from Senegal for West and East African lineages of Rift Valley fever virus. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Ndiaye, El; Fall, Gamou; Gaye, Alioune; Bob, Ndeye; Talla, Cheikh; Diagne, Cheikh; Diallo, Diawo; BA, Yamar; Dia, Ibrahima; Kohl, Alain; Sall, Amadou; Diallo, Mawlouth
• Is Part Of: Parasites & vectors. Volume 9:Issue 1(2016)
• Page Start: 1
• Page End: 9
• Publication Date: 2016-12
• Subjects: Mosquito -- Oral infection -- Vector competence -- Viral genetic diversity -- Rift Valley fever virus -- Senegal; Parasitism -- Periodicals; Parasites -- Periodicals; Vector-pathogen relationships -- Periodicals; Animals as carriers of disease -- Periodicals; Insects as carriers of disease -- Periodicals; 616.96
• DOI: 10.1186/s13071-016-1383-y
• Languages: English
• ISSNs: 1756-3305

Abstract

Abstract Background Rift Valley fever virus (RVFV;Phlebovirus, Bunyaviridae ) is a mosquito–borne, zoonotic pathogen. In Senegal, RVFV was first isolated in 1974 fromAedes dalzieli (Theobald) and thereafter fromAe. fowleri (de Charmoy), Ae. ochraceus Theobald, Ae. vexans (Meigen), Culex poicilipes (Theobald), Mansonia africana (Theobald) andMa. uniformis (Theobald). However, the vector competence of these local species has never been demonstrated making hypothetical the transmission cycle proposed for West Africa based on serological data and mosquito isolates. Methods Aedes vexans andCx. poicilipes, two common mosquito species most frequently associated with RVFV in Senegal, andCx. quinquefasciatus, the most common domestic species, were assessed after oral feeding with three RVFV strains of the West and East/central African lineages. Fully engorged mosquitoes (420Ae. vexans, 563Cx. quinquefasciatus and 380Cx. poicilipes ) were maintained at 27 ± 1 °C and 70–80 % relative humidity. The saliva, legs/wings and bodies were tested individually for the RVFV genome using real-time RT-PCR at 5, 10, 15 and 20 days post exposure (dpe) to estimate the infection, dissemination, and transmission rates. Genotypic characterisation of the 3 strains used were performed to identify factors underlying the different patterns of transmission. Results The infection rates varied between 30.0–85.0 % forAe. vexans, 3.3–27 % forCx. quinquefasciatus and 8.3–46.7 % forCx. poicilipes, and the dissemination rates varied between 10.5–37 % forAe. vexans, 9.5–28.6 % forCx. quinquefasciatus and 3.0–40.9 % forCx. poicilipes . However only the East African lineage was transmitted, with transmission rates varying between 13.3–33.3 % inAe. vexan s, 50 % inCx. quinquefasciatus and 11.1 % inCx. poicilipes. Culex mosquitoes were less susceptible to infection thanAe. vexans . Compared to other strains, amino acid variation in the NSs M segment proteins of the East African RVFV lineage human-derived strain SH172805, might explain the differences in transmission potential. Conclusion Our findings revealed that all the species tested were competent for RVFV with a significant more important role ofAe. vexans compared toCulex species and a highest potential of the East African lineage to be transmitted.