Murray Valley encephalitis virus

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? Murray Valley encephalitis virus
Virus classification
Group: Group IV ((+)ssRNA) Family: Flaviviridae Genus: Flavivirus Species: Murray Valley encephalitis virus

Murray Valley encephalitis virus (MVEV) is a zoonotic flavivirus endemic to northern Australia and Papua New Guinea. It is the causal agent of Murray Valley encephalitis (previously known as Australian encephalitis) and in humans can cause permanent neurological disease or death. MVEV is related to Kunjin virus which has a similar ecology but has a lower morbidity rate.

MVEV is a mosquito-borne virus that is maintained in a bird-mosquito-bird cycle. Water birds from the Ciconiiformes order, including herons and cormorants, provide the natural reservoir for MVEV^[1]. The major mosquito vector is Culex annulirostris. Human infection occurs through bites from infected mosquitoes.

The first epidemics of MVE occurred in 1917 and 1918 in Southeastern Australia following years of high rainfall. The virus was isolated from human samples in 1951 during an epidemic^[2].

The major clinical feature of MVEV is fever. Other symptoms may include seizures, nausea and diarrhoea in children and headaches, lethargy and confusion in adults. MVEV infection is usually subclinical with as few as 1 in 1000 incidents causing illness, most of them in children. Of infections that result in illness, mortality rate is estimated at 20%. Permanent neurological damage occurs in 50% of survivors.

[edit] References

1. ^ Marshall, ID, Brown, BK, Keith, K, Gard, GP, Thibos, E (1982). Variation in arbovirus infection rates in species of birds sampled in a serological survey during an encephalitis epidemic in the Murray Valley of South-eastern Austalia, February 1972. Australian Journal of Expermental Biology and Medical Science. 60(5):471–478.
2. ^ French, EL. (1952). Murray Valley encephalitis isolation and characterization of the aetiological agent. Medical Journal of Australia. 1(4):100–103.