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

Ndiaye, E. H. et al. (2016) 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. Parasites and Vectors, 9, 94. (doi:10.1186/s13071-016-1383-y) (PMID:26897521) (PMCID:PMC4761212)

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Abstract

Background Rift Valley fever virus (RVFV; Phlebovirus, Bunyaviridae) is a mosquito–borne, zoonotic pathogen. In Senegal, RVFV was first isolated in 1974 from Aedes dalzieli (Theobald) and thereafter from Ae. fowleri (de Charmoy), Ae. ochraceus Theobald, Ae. vexans (Meigen), Culex poicilipes (Theobald), Mansonia africana (Theobald) and Ma. 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 and Cx. poicilipes, two common mosquito species most frequently associated with RVFV in Senegal, and Cx. 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 (420 Ae. vexans, 563 Cx. quinquefasciatus and 380 Cx. 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 % for Ae. vexans, 3.3–27 % for Cx. quinquefasciatus and 8.3–46.7 % for Cx. poicilipes, and the dissemination rates varied between 10.5–37 % for Ae. vexans, 9.5–28.6 % for Cx. quinquefasciatus and 3.0–40.9 % for Cx. poicilipes. However only the East African lineage was transmitted, with transmission rates varying between 13.3–33.3 % in Ae. vexans, 50 % in Cx. quinquefasciatus and 11.1 % in Cx. poicilipes. Culex mosquitoes were less susceptible to infection than Ae. 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 of Ae. vexans compared to Culex species and a highest potential of the East African lineage to be transmitted.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Kohl, Professor Alain
Authors: Ndiaye, E. H., Gamou, F., Alioune, G., Bob Ndeye, S., Cheikh, T., Diagne, C. T., Diallo, D., Yamar, B.A., Dia, I., Kohl, A., Sall, A. A., and Diallo, M.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:Parasites and Vectors
Publisher:BioMed Central Ltd.
ISSN:1756-3305
ISSN (Online):1756-3305
Copyright Holders:Copyright © 2016 Ndiaye et al.
First Published:First published in Parasites and Vectors 9:94
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
656551Arbovirus interactions with arthropod hostsAlain KohlMedical Research Council (MRC)MC_UU_12014/8MVLS III - CENTRE FOR VIRUS RESEARCH