Mosquito culling ramping up in northern Western Australia after Murray Valley Encephalitis kills two people

A health alert has been issued and mosquito control programs stepped up after two deaths from a mosquito-borne virus in Western Australia's Pilbara.

Murray Valley Encephalitis (MVE) virus is endemic to northern WA and is transferred to humans by mosquitoes.

For the most part, it is a mild illness, but in rare cases, it can cause a brain infection, potentially triggering lifelong symptoms, and sometimes death.

Around one in 800 people infected by MVE virus develop severe illness.

There have been four recorded cases in WA in 2024.

"It's important to note there is actually no vaccine or specific treatments for Murray Valley Encephalitis," WA Health Department managing scientist Jay Nicholson said.

"So the only effective protection against infection is to take precautions to avoid mosquito bites."

Dr Nicholson said the elderly and very young were particularly at risk from the virus.

Residents, tourists urged to cover, repel and clean

Winter is peak tourist season in WA's north, and the Health Department said it was expecting an increase in travellers in the coming weeks.

The department is asking residents and tourists to safeguard themselves by wearing protective clothing, applying effective mosquito repellent, and keeping vegetation around living areas short to discourage mosquitoes.

Dr Nicholson encouraged holiday-makers to check the condition of caravans and camping equipment before starting a trip.

"If you've got a caravan from last year, you may have insect screens fitted — just make sure they're in good working condition," Dr Nicholson said.

"If you are camping outside, it's always a very good idea to have either mosquito nets or mosquito-proof tents available."

Pilbara town increasing mosquito culling

In Port Hedland, 1,600km north of Perth, efforts to reduce mosquito numbers are ramping up.

"We've already escalated our programs … our ongoing monitoring of sites has increased as well," Port Hedland environmental services manager Michael Cuvalo said.

"We're also definitely urging the community to notify us if they observe an increase in mosquito numbers in their areas or where they work."

Mr Cuvalo said the key to controlling mosquito numbers was destroying mosquito eggs, which were laid around water bodies and wetlands.

These areas can be difficult, and sometimes dangerous, for humans to access. But the town has recently acquired a drone to do the job.

"It's a phenomenal piece of technology," Mr Cuvalo said.

"It allows us to deliver chemical treatments to areas of between 12 and 15 hectares a day.

"Whereas previously that's been done on foot by hand walking through swamps … where at best and with multiple staff we would be treating maybe 4 or 5 hectares a day. So the ability to destroy mosquitoes has increased.

The health alert also includes the Gascoyne and Midwest regions.