Kimberley residents and travellers are being urged to protect themselves against mosquito bites, following the first Murray Valley encephalitis (MVE) detection in the region this year.
The Department of Health warning follows MVE virus being found in sentinel chicken flocks in the east Kimberley during the wet season.
Sentinel chickens are used to monitor and provide an early warning system for mosquito-borne virus activity.
WA Health's Managing Scientist – Biological Hazards Dr Andrew Jardine said that Murray Valley encephalitis virus was only transmitted by mosquitoes.
"While the risk of being infected and becoming unwell is low, the illness caused by the virus can be severe and even fatal," he said.
"The only effective protection against infection is to take precautions to avoid mosquito bites."
MVE virus activity occurs in the Kimberley region in most years following wet season rainfall and can also occur in the Pilbara region in some years. This year significant activity has also been detected in other Australian States and Territories.
While there have been no human cases of MVE reported in WA in 2023, the Northern Territory and Victoria recently issued public health alerts due to deaths in those jurisdictions.
Initial symptoms of MVE include fever, drowsiness, headache, stiff neck, nausea and dizziness.
"People experiencing these symptoms should seek medical advice as soon as possible," Dr Jardine said.
"In severe cases, people may experience seizures, lapse into a coma, be left with permanent brain damage or die."
In young children, fever might be the only early sign of infection. Parents should see their doctor or local health service if concerned, particularly if their child experiences drowsiness, floppiness, irritability, poor feeding, or general distress.
Dr Jardine said that recent significant rainfall and flooding in the Kimberley had created ideal breeding conditions for mosquitoes across extensive seasonal wetlands, increasing the risk of being exposed to MVE and a range of other local mosquito-borne viruses.
"In addition to local mosquito-borne virus activity, there is the possibility that Japanese encephalitis virus may also become active in WA," he said.
"It is now more important than ever to take measures to prevent mosquito bites."
Japanese encephalitis (JE) is a rare mosquito-borne disease, that has been detected in the Northern Territory, and all other mainland States.
The Department is carrying out enhanced mosquito-borne disease surveillance activities in the Kimberley to monitor any risk to public health.
To protect against mosquito bites:
- if possible, avoid being outdoors at dawn and early evening
- wear long, loose-fitting, light-coloured clothing outdoors
- apply an effective personal mosquito repellent containing diethyltoluamide (DEET), picaridin or Oil of Lemon Eucalyptus (also known as PMD) evenly to all areas of exposed skin and always follow the label instructions
- ensure insect screens are installed and in good condition on houses and caravans
- use mosquito nets and mosquito-proof tents if sleeping outside
- use mosquito coils and mosquito lanterns and apply barrier sprays containing bifenthrin in patio and outdoor areas around houses
- ensure babies and children are wearing suitable clothing, shoes/socks, and use bed nets or other insect screening
- keep grass/weeds and other vegetation short
- remove water holding containers from around the home and garden to ensure mosquitoes do not breed in your backyard.
