First transmission of Murray Valley encephalitis in 12 years confirmed in the Riverina

With mozzies still thick across the Riverina, there’s a timely warning to cover up and avoid being bitten after a case of Murray Valley encephalitis (MVE) virus infection has been identified.

A man in his 60s has become the first case in NSW for this mosquito season and the first confirmed transmission of the virus in the state since 2011.

He was potentially exposed to infected mosquitoes in January around the Temora Shire, Edward River Shire or Murrumbidgee Council areas and has been admitted to hospital.

While MVE is rare and most infected people will not have symptoms, a small number of people develop more serious inflammation of the brain.

Public health epidemiologist Keira Glasgow said this confirmed case followed the detection of MVE in mosquitoes and sentinel chickens in parts of western and southern NSW.

“There is no vaccination or specific treatment for Murray Valley encephalitis, so we urge the community to do everything they can to protect themselves against mosquito bites,” she said.

“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, Kunjin and Barmah Forest viruses.”

She explained that a small proportion of those infected will exhibit symptoms such as fever, headache, nausea, vomiting, loss of appetite, diarrhoea, and muscle aches.

“Signs of severe infection include severe headache, neck stiffness, sensitivity to bright lights, drowsiness, confusion, seizures, and loss of consciousness,” Ms Glasgow said, adding that the number of MVE detections this season was concerning.

NSW Health has established an expert advisory panel on mosquito control and management with medical entomologists from across Australia.

“We are looking closely at the various approaches to mosquito control in different environments and in areas with different population densities to help inform our approach to mosquito control and management in NSW,” said Ms Glasgow.

Remember to protect yourself from mosquito bites by:

• 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

• Reapplying repellent regularly, particularly after swimming, being sure to always apply sunscreen first and then apply repellent

• Covering openings such as windows and doors with insect screens and checking there are no gaps in them

• Removing items that might collect water (such as old tyres and empty pots) outside your house where mosquitoes can breed

• Improving drainage on your property so that water does not become stagnant

• 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 NSW Health’s mosquito-borne diseases page here.