Murray Valley encephalitis virus detected in NSW

11 January 2023

Communities across NSW are encouraged to take measures to protect themselves against mosquito bites following the detection of Murray Valley encephalitis (MVE) virus in a mosquito in Menindee.

MVE virus is spread by mosquitos from infected animals to humans. Rarely, it causes severe neurological illness with headache, convulsions and reduced consciousness in some cases.

The virus cannot be transmitted between humans, and people cannot get the virus by touching an infected animal or eating animal products.

The primary hosts of MVE virus are waterbirds such as herons and egrets. Detection of MVE is likely related to recent rainfall and flooding. Locally acquired cases of MVE were last identified in NSW in 2011.

Executive Director of Health Protection NSW, Dr Richard Broome said most people who are infected with the virus that causes MVE do not have any symptoms.

"Only a small proportion of people infected with the virus will experience symptoms, which include fever, headache, nausea, vomiting, loss of appetite, diarrhoea, and muscle aches. Among those who get a severe infection, some may die or have lifelong neurological complications," Dr Broome said.

"There is no vaccination or specific treatment for MVE and the best way to avoid infection is to avoid being bitten by mosquitoes, which are most active between dusk and dawn.

"Avoiding mosquito bites will also protect against other mosquito-borne infections including Japanese encephalitis, Ross River Fever and Barmah Forest virus."

People in NSW are urged to take actions to prevent mosquito bites to protect against all mosquito-borne viruses. Protect yourself and your family by:

  • covering openings such as windows and doors with insect screens and checking there are no have gaps in them
  • removing items that might collect water (such as old tyres, empty pots) outside your house where mosquitoes can breed
  • improving drainage on your property so that water does not become stagnant
  • wearing light, loose-fitting long-sleeved shirts, long pants and covered footwear and socks, especially around dusk and dawn
  • applying repellent to all areas of exposed skin, using repellents that contain DEET, picaridin, or oil of lemon eucalyptus
  • re-applying repellent regularly, particularly after swimming, being sure to always apply sunscreen first and then apply repellent
  • using insecticide sprays, vapour dispensing units and mosquito coils to repel mosquitos (mosquito coils should only be used outside).

For further information and ways to protect yourself visit the NSW Health website.