Vector competence of three Australian mosquitoes, Verrallina carmenti, Verraullina lineata, and Mansonia septempunctata (Diptera: Culicidae), for Ross River virus.

The vector competence of Verrallina carmenti (Edwards), Verrallina lineata (Taylor), and Mansonia septempunctata (Theobald) (Diptera: Culicidae) from north Queensland, Australia, was tested using two isolates of Ross River virus (family Togaviridae, genus Alphavirus, RRV). All three species were tested using RRV isolate RR102MP (ex-Cairns, Queensland, Australia), whereas Ve. carmenti and Ve. lineata also were tested using RR2186 (ex-Bourke, New South Wales, Australia). Transmission was tested using the capillary tube method, with infection of mosquito bodies and saliva determined using cell culture. Infection with RR102MP resulted in 27.5% of Ve. carmenti, 19.2% of Ve. lineata and 13.3% of Ma. septempunctata transmitting virus. When Ve. carmenti and Ve. lineata were infected with RR2186, transmission rates for both species were generally < 10%, although a transmission rate of 25% was recorded for Ve. lineata exposed to high titer virus. These results indicated that the three mosquito species have the potential to contribute to local transmission cycles.