Mur·ray Val·ley en·ceph·a·li·tis

a severe encephalitis with a high mortality rate occurring in the Murray Valley of Australia; the disease is most severe in children and is characterized by headache, fever, malaise, drowsiness or convulsions, and rigidity of the neck; extensive brain damage may result; it is caused by the Murray Valley encephalitis virus (genus Flavivirus).

Synonym(s): Australian X disease, Australian X encephalitis

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Murray Valley encephalitis

A rare, Japanese encephalitis-like disease caused by a flavivirus-group B togavirus, which occurs in small epidemic clusters in Murray Valley and elsewhere in Victoria and New South Wales, Australia. It is maintained by a cycle between wild birds and mosquitoes (Culex annulirostris), and is favoured by hot weather.

Clinical findings
Usually asymptomatic; if symptomatic, fever, headache, nausea, vomiting, loss of appetite, diarrhoea, muscle aches. Neurological changes, if present, include severe headache, neck stiffness, photophobia, drowsiness and confusion. Rare cases may be characterised by co-ordination and speech defects, seizures, loss of consciousness, coma and death; the latter cases may have residual neurologic dysfunction.

Mur·ray Val·ley en·ceph·a·li·tis

(mŭr'ē val'ē en-sef'ă-līt'is)

A severe encephalitis with a high mortality rate occurring in the Murray Valley of Australia; the disease is most severe in children and is characterized by headache, fever, malaise, drowsiness or convulsions, and rigidity of the neck; extensive brain damage may result; it is caused by the Murray Valley encephalitis virus (genus Flavivirus).
Synonym(s): Australian X disease.

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

Murray Valley,

location in Australia where epidemics occurred in 1950 and 1951.

Murray Valley disease - Synonym(s): Murray Valley encephalitis

Murray Valley encephalitis - a severe encephalitis with high mortality. Synonym(s): Australian X disease; Australian X encephalitis; Murray Valley disease

Murray Valley virus - a group B arbovirus that causes Murray Valley encephalitis. Synonym(s): Australian X disease virus; MVE virus