Experimental transmission of West Nile Virus and Rift Valley Fever Virus by Culex pipiens from Lebanon

Renée Zakhia (1) , Laurence Mousson (2) , Marie Vazeille (2) , Nabil Haddad (1) , Anna-Bella Failloux (2)

1 Laboratory of Immunology and Vector Borne Diseases [Fanar]
2 Arbovirus et Insectes Vecteurs - Arboviruses and Insect Vectors

West Nile virus (WNV) and Rift Valley fever virus (RVFV) are two emerging arboviruses transmitted by Culex pipiens species that includes two biotypes: pipiens and molestus. In Lebanon, human cases caused by WNV and RVFV have never been reported. However, the introduction of these viruses in the country is likely to occur through the migratory birds and animal trades. In this study, we evaluated the ability of Cx. pipiens, a predominant mosquito species in urban and rural regions in Lebanon, to transmit WNV and RVFV. Culex egg rafts were collected in the West Bekaa district, east of Lebanon and adult females of Cx. pipiens were experimentally infected with WNV and RVFV Clone 13 strain at titers of 1.6×10 8 and 1.33×10 7 plaque forming units (PFU)/mL, respectively. We estimated viral infection, dissemination and transmission at 3, 7, 14 and 19 days post infection (dpi). Results showed that infection was higher for WNV than for RVFV from 3 dpi to 19 dpi. Viral dissemination and transmission started from 3 dpi for WNV; and only from 19 dpi for RVFV. Moreover, Cx. pipiens were able to excrete in saliva a higher number of viral particles of WNV (1028 ± 405 PFU/saliva at 19 dpi) than RVFV (42 PFU/saliva at 19 dpi).

Domaines: Microbiologie et Parasitologie

Renée Zakhia, Laurence Mousson, Marie Vazeille, Nabil Haddad, Anna-Bella Failloux. Experimental transmission of West Nile Virus and Rift Valley Fever Virus by Culex pipiens from Lebanon. PLoS Neglected Tropical Diseases, 2018, 12 (1), pp.e0005983. ⟨10.1371/journal.pntd.0005983⟩. ⟨pasteur-01707372⟩