New Murray Valley encephalitis detections in Murrumbidgee

A sentinel chicken used for surveillance of viruses in the Murrumbidgee Local Health District’s Leeton flock has tested positive for MVE antibodies after a collection on 29 January 2023.

MVE was also detected in mosquito trappings at Griffith on 6 February 2023.

Acting Director of Public Health, Murrumbidgee Local Health District, Alison Nikitas, said detections in sentinel chickens suggest that virus levels within mosquito populations are high and there is potential for the virus to spread to people.

“It remains very important for the community to remain aware of the risks and to continue taking precautions against mosquito bites,” Ms Nikitas said.

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

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

Ms Nikitas said MVE virus is spread to humans by infected mosquitoes. Rarely, it causes severe neurological illness.

“Only a small proportion of people infected with the virus will have any symptoms, which include fever, headache, nausea, vomiting, loss of appetite, diarrhoea, and muscle aches. Among those who get a severe infection, lifelong neurological complications or death can result,” she said.

“Signs of severe infection include severe headache, neck stiffness, sensitivity to bright lights, drowsiness, confusion, seizures, and loss of consciousness.

The primary hosts of MVE and Japanese encephalitis virus (JEV) are wild waterbirds such as herons and egrets. Recent detections of MVE virus are likely related to recent flooding and increased numbers of waterbirds.

You can protect yourself and your family 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
• re-applying 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, 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).