Isolation and Characterization of Sylvatic Mosquito-Borne Viruses in Trinidad: Enzootic Transmission and a New Potential Vector of Mucambo Virus

摘要

Mosquito surveillance was carried out in three forested regions of Trinidad during July 2007–March 2009. A total of 185,397 mosquitoes representing at least 46 species was collected, divided into pools of 1–50 mosquitoes according to species and sex, and screened for arboviruses using cytopathic effect assays on Vero cell monolayers. Eighty-five viruses were isolated, including members of the genera Alphavirus (Mucambo virus; MUCV) and Orthobunyavirus (Caraparu, Oriboca, Bimiti, and Wyeomyia viruses). Species of the Culex subgenus Melanoconion accounted for 56% of the total number of mosquitoes collected and 97% of the viruses isolated; Cx. (Mel.) portesi accounted for 92% of virus isolations. Our results also implicate for the first time Aedes (Ochlerotatus) hortator as a potential vector of MUCV. Phylogenetic analyses of 43 MUCV strains suggest population subdivision within Trinidad, consistent with the hypothesis of enzootic maintenance in localized rodent populations.