Kunjin Virus

Kunjin virus (KUNV), a member of West Nile virus (WNV) lineage 1, was isolated from an Australian mosquito in 1960. Similar to other WNV strains, KUNV infection is usually asymptomatic or causes mild illness, but occasionally produces severe neurological disorders. Unlike most WNV strains, KUNV seldom causes disease in horses. In 2011, however, a mutant strain caused a large outbreak of severe neurological disease in horses and one mild human case. Culex mosquitoes, especially Cx. annulirostris, are KUNV’s primary vectors. Wading birds, particularly night herons and egrets, serve as reservoir hosts. KUNV is primarily confined to northwestern Australia, but may enter south/central regions after excessive rainfall and flooding. Rates of seroprevalance and infection in sentinel chickens and feral rabbits should be closely monitored to detect the expansion of KUNV’s range and pathogenicity. This is particularly important since the 2011 horse outbreak occurred in dry, coastal regions, previously believed to be virus free.