Murray Valley encephalitis
Murray Valley encephalitis (MVE) is an uncommon but potentially fatal disease.
It can occur after being bitten by a mosquito carrying the MVE virus.
MVE is the most serious mosquito-borne disease that occurs in the Northern Territory (NT).
Where it's found
Although MVE can occur throughout Australia, it is most common in northern Australia and the Barkly region of the NT.
In the NT, the MVE virus is present from February to July in the Top End and Barkly region. It can also extend into the Barkley and Central Australia in wet years.
In the rest of Australia, the virus is present in the north-west of Western Australia and inland North Queensland during most years.
Most cases are detected between March and May.
How it spreads
The MVE virus is spread by the bite of an infected mosquito (usually Culex annulirostris, also known as the common-banded mosquito).
Only about one person in 1,000 who is bitten by an infected mosquito will become unwell with MVE.
Who is at risk
People most at risk are babies, young children and newcomers to a region where MVE occurs.
Symptoms
Symptoms of MVE usually appear 5 to 28 days after being bitten by an infected mosquito.
The early symptoms include:
- headache
- fever
- nausea
- vomiting
- muscle aches,
These symptoms can then progress to drowsiness, confusion, seizures or fits (especially in young children).
In severe cases, it can lead to delirium and coma.
Diagnosis
A blood test is available to test for recent or past MVE infection.
Treatment
There is no specific treatment or vaccine available for MVE.
The treatment of severe MVE is supportive and often requires admission to an intensive care unit.
Prevention
The only protection from MVE is to avoid being bitten by mosquitoes, particularly those visiting and camping:
- in or near swamp or river systems during the evening and night
- in rural areas near sites of relatively high-mosquito activity.
Mosquito protection for young children and babies is absolutely essential.
Read more about protecting yourself from mosquitoes.
Information for health professionals
To find out more, go to the NT Health website.
Contact
Contact your nearest Centre for Disease Control on the NT Health website.