Murray Valley encephalitis

noun

Mur·​ray Val·​ley encephalitis ˈmər-ē-ˈval-ē- 

: an encephalitis endemic in northern Australia and Papua New Guinea that is caused by a flavivirus (Orthoflavivirus murrayense) transmitted by mosquitoes (especially Culex annulirostris) and that is often asymptomatic but may cause serious potentially fatal disease