Flaviviruses isolated from mosquitoes collected during the first recorded outbreak of Japanese encephalitis virus on Cape York Peninsula, Australia

In response to an outbreak of Japanese encephalitis (JE) virus on Cape York Peninsula, Australia, in 1998, mosquitoes were collected using CO2 and oct enol-baited Centers for Disease Control and Prevention light traps. A total of 35,235 adult mosquitoes, comprising 31 species, were processed for viru s isolation. No isolates of JE virus were recovered from these mosquitoes. However, 18 isolates of Kokobera virus, another flavivirus were obtained fr om Culex annulirostris. Twelve isolates were from western Cape York (minimu m infection rate (MIR) of 0.61: 1,000 mosquitoes) and 6 were from the North ern Peninsula Area (MIR of 1.0:1,000). Potential explanations for the failu re to detect JE virus in mosquitoes collected from Cape York Peninsula incl ude the timing of collections, the presence of alternative bloodmeal hosts, differences in pig husbandry, asynchronous porcine seroconversion, and the presence of other flaviviruses.