Murray Valley encephalitis

Murray Valley encephalitis (MVE) is a potentially fatal disease that occurs after being bitten by a mosquito carrying the MVE virus.

Children are at greater risk, with the very young and older people more likely to have long term health problems after an infection.

The mosquitoes that spread MVE are most active at dawn and dusk.

It is considered to be one of the most severe illnesses transmitted by mosquitoes in the Northern Territory (NT), along with Japanese encephalitis.

Alert to health professionals

• Health alert - Murray Valley encephalitis - 20 May 2026 PDF (560.2 KB)

Current situation

There have recently been confirmed cases of Murray Valley encephalitis (MVE) in Alice Springs and MVE virus has also been detected in mosquitoes in the Greater Darwin region. Increased rainfall during the wet season has led to higher mosquito numbers across the NT, increasing the risk of mosquito-borne disease. MVE is a rare but potentially serious infection spread by infected mosquitoes.

Mosquito surveillance and control activities are underway to help reduce mosquito breeding. Clinicians across the NT are advised to consider MVE as a differential diagnosis when assessing patients.

Seasonal risk

Mosquitos are an active part of the Northern Territory (NT) environment.

There is an increase risk of MVE between February and July, most cases are detected between March and May.

Notifiable disease

MVE is a notifiable disease.

Information for health professionals

Information for the public