Metagenomic analysis of coastal Kenya female Aedes aegypti mosquito RNA metaviromes reveal presence of diverse insect specific viruses

Abstract

Background: Coastal Kenya has experienced repeated outbreaks of Chikungunya (CHIKV) and Dengue (DENV) viruses mediated by competent Aedes aegypti mosquito populations. These mosquitoes harbor insect specific viruses (ISVs), some of which can prevent arboviral transmission. However, there has been no systematic molecular entomological surveillance in coastal Kenya and the diversity of viruses in local Aedes aegypti populations remains largely unknown. Methods: To obtain a snapshot of the Aedes aegypti viromes from coastal Kenya, we took advantage of a cross-sectional survey of mosquitoes to determine the prevalence of Zika virus. We collected adult mosquitoes using lured Biogent’s sentinel traps at 16 different localities along the Kenyan coast between May to September 2017. Pools of 20 female Aedes aegypti mosquitoes were generated following grouping by morphological characteristics. Presence of arboviruses in the mosquito pools was determined using virus-specific and genera-specific primers with real-time PCR. Metagenomic next generation sequencing (mNGS) on Illumina Miseq and analysis was used to characterize the virome. Results: A total of 16,520 female Aedes aegypti grouped into 826 pools were analysed. Flaviviruses were detected in 69/826 (8.4%) pools by real time PCR. Sequencing generated 8,459/971,754 (0.87%) clean reads that were taxonomically assigned to 16 and 28 viral families and species, respectively. The family Phenuiviridae represented by Phasi Charoen-like phasivirus (PCLV) species was the most abundant, detected in 64/73 (87%) mosquito pools. No pathogenic viruses were identified by mNGS. Phylogenetic analysis revealed local PCLV and Cell fusing agent virus (CFAV) were distinct from global sequences. Conclusions: Our data provides information about virus diversity and composition of the Aedes aegypti mosquitoes from coastal Kenya and contributes to the body of knowledge of the Aedes aegypti virome. To the best of our knowledge, this is the first study to provide this information from this region.