Abstract:
Mosquitoes in the Aedes and Culex genera are considered the main vectors of pathogenic
flaviviruses worldwide. Entomological surveillance using universal flavivirus sets of primers in
mosquitoes can detect not only pathogenic viruses but also insect-specific ones. It is hypothesized
that insect-specific flaviviruses, which naturally infect these mosquitoes, may influence their vector
competence for zoonotic arboviruses. Here, entomological surveillance was performed between
January 2014 and May 2018 in five different provinces in the northeastern parts of South Africa, with
the aim of identifying circulating flaviviruses. Mosquitoes were sampled using different carbon
dioxide trap types. Overall, 64,603 adult mosquitoes were collected, which were screened by RT-PCR
and sequencing. In total, 17 pools were found positive for insect-specific Flaviviruses in the mosquito
genera Aedes (12/17, 70.59%) and Anopheles (5/17, 29.41%). No insect-specific viruses were detected
in Culex species. Cell-fusing agent viruses were detected in Aedes aegypti and Aedes caballus. A range
of anopheline mosquitoes, including Anopheles coustani, An. squamosus and An. maculipalpis, were
positive for Culex flavivirus-like and Anopheles flaviviruses. These results confirm the presence of
insect-specific flaviviruses in mosquito populations in South Africa, expands their geographical
range and indicates potential mosquito species as vector species.
