Evolutionary analyses of Sindbis virus strains isolated from mosquitoes in Kenya.

Sindbis virus (SINV) is a mosquito borne virus maintained in nature in a mosquito-bird cycle, with human outbreaks known to occur in Northern Europe and parts of Africa. We analyzed five SINV strains isolated in Kenya from five different mosquito species and geographic locations between 2007 and 2013. Phylogenetic relationships and evolutionary inferences were performed using maximum likelihood and Bayesian phylogenetic inference approaches. Selection analyses were carried out based on the virus envelope glycoproteins (E1, E2) and non-structural protein (nsP4) genes. Phylogenetic analysis revealed that all the Kenyan SINV isolates belonged to genotype 1 with selection analyses suggesting that SINV E1, E2 and nsP4 protein encoding genes were predominantly evolving under negative selection.