Abstract
Rift Valley fever virus (RVFV) causes a zoonotic mosquito-borne haemorrhagic disease
that emerges to produce rapid large-scale outbreaks in livestock within sub-Saharan Africa. A range
of mosquito species in Africa have been shown to transmit RVFV, and recent studies have assessed
whether temperate mosquito species are also capable of transmission. In order to support vector
competence studies, the ability to visualize virus localization in mosquito cells and tissue would
enhance the understanding of the infection process within the mosquito body. Here, the application
of in situ hybridization utilizing RNAscope® to detect RVFV infection within the mosquito species,
Culex pipiens, derived from the United Kingdom was demonstrated. Extensive RVFV replication was
detected in many tissues of the mosquito with the notable exception of the interior of ovarian follicles.