Abstract:
Insect-specific flaviviruses (ISFs), although not known to be pathogenic to humans and
animals, can modulate the transmission of arboviruses by mosquitoes. In this study, we screened
6665 host-seeking, gravid and blood-fed mosquitoes for infection with flaviviruses and assessed the
vertebrate hosts of the blood-fed mosquitoes sampled in Baringo and Kajiado counties; both dryland
ecosystem counties in the Kenyan Rift Valley. Sequence fragments of two ISFs were detected. Cuacua
virus (CuCuV) was found in three blood-fed Mansonia (Ma.) africana. The genome was sequenced
by next-generation sequencing (NGS), confirming 95.8% nucleotide sequence identity to CuCuV
detected in Mansonia sp. in Mozambique. Sequence fragments of a potential novel ISF showing
nucleotide identity of 72% to Aedes flavivirus virus were detected in individual blood-fed Aedes
aegypti, Anopheles gambiae s.l., Ma. africana and Culex (Cx.) univittatus, all having fed on human blood.
Blood-meal analysis revealed that the collected mosquitoes fed on diverse hosts, primarily humans
and livestock, with a minor representation of wild mammals, amphibians and birds. The potential
impact of the detected ISFs on arbovirus transmission requires further research.
