Vector Competence of Mosquitoes (Diptera: Culicidae) from Maroochy Shire, Australia, for Barmah Forest Virus

Abstract

Mosquitoes were collected in light traps from Maroochy Shire and fed on blood containing the sympatric BF1611 strain of Barmah Forest virus (BF). Saltmarsh Aedes vigilax (Skuse) and freshwater Aedes procax (Skuse) were highly susceptible to infection, with ID₅₀s of 10^1.7 and 10^1.5 African green monkey kidney (Vero) cell culture infectious dose, 50% endpoint (CCID₅₀) per mosquito, respectively, followed by Aedes multiplex (Theobald) and Aedes funereus (Theobald) with 10^2.5 and 10^3.2 CCID₅₀ per mosquito, respectively. Culex australicus Dobrotworsky & Drummond and Mansonia uniformis (Theobald) that were fed 10^3.6 CCID₅₀ (Vero) BF per mosquito had infection rates of 28 and 60%, respectively. Only 8% of freshwater Culex annulirostris Skuse fed the same viral dose were infected. Evidence of virus transmission to mice was found with Ae. vigilax and Ae. procax, with transmission rates of 65 and 88% at 11–12 d after infection, respectively. Based on adult abundance, susceptibility to infection, and efficiency of virus transmission, Ae. vigilax would appear to be the most important vector of BF in Maroochy Shire.