Molecular characterization of three Zika flaviviruses obtained from sylvatic mosquitoes in the Central African Republic.

Zika virus (ZIKV) is an emerging pathogen belonging to the Spondweni serocomplex within the genus Flavivirus. It has been isolated from several mosquito species. Two lineages of ZIKV have been defined by polyprotein homology. Using high-throughput sequencing, we obtained and characterized three complete genomes of ZIKV isolated between 1976 and 1980 in the Central African Republic. The three viruses were isolated from two species of mosquito, Aedes africanus and Ae. opok. Two sequences from Ae. africanus had 99.9% nucleotide sequence identity and 100% amino acid identity, whereas the complete genome obtained from Ae. opok had 98.3% nucleotide identity and 99.4% amino acid identity with the other two genomes. Phylogenetic analysis based on the amino acid sequence of the polyprotein showed that the three ZIKV strains clustered together but diverged from all other ZIKV strains. Our molecular data suggest that a different subtype of West African ZIKV strains circulated in Aedes species in Central Africa.