Mosquito warning as new Murray Valley encephalitis case found in WA

A new case of Murray Valley encephalitis (MVE) has been confirmed in Western Australia.

The adult was potentially exposed to infected mosquitoes while travelling in the West Kimberley and the Northern Territory.

This is the third confirmed case of MVE reported in WA since 2018 (with two of the cases this year). Nationally, there have been 13 cases of MVE reported so far in 2023.

Department of Health Managing Scientist Dr Andrew Jardine said the new case followed recent MVE virus detections in mosquitoes and sentinel chickens across the north of the State and sadly, the death of a WA child from MVE in March.

“I am warning the community – don’t be blasé about mozzie bites,” Dr Jardine said.

“Protecting yourself from mosquito bites is the best thing you can do to avoid the virus – there is no vaccine or specific treatment for MVE.

“Avoiding bites will also protect against other infections carried by mosquitoes including Japanese encephalitis and Kunjin viruses.

“While the risk of getting infected and becoming sick is low, the illness caused by MVE can be severe and even deadly.”

Dr Jardine said first symptoms included fever, drowsiness, headache, stiff neck, nausea, and dizziness.

“If you have these symptoms, seek medical advice as soon as you can,” he said.

“In severe cases, people can have 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.”

Steps to avoid bites:

  • Cover up outside – wear loose, long-sleeved, light-coloured clothing, particularly at dawn and dusk when mosquitoes are most active.
  • Ensure babies and children are adequately protected against mosquito bites, with suitable clothing, shoes/socks, bed nets or other forms of insect screening.
  • Apply mosquito repellent, containing picaridin, DEET or oil of lemon eucalyptus (OLE – also known as PMD), evenly to all areas of exposed skin. Read the instructions to find out how often you should reapply repellent.
  • Mosquito wristbands and patches are not recommended as there is no evidence that these provide good protection against mosquito bites.
  • Avoid outdoor exposure, particularly at dawn and early evening.

– You can also limit the number of mosquitoes in and around your home:

– Cut grass often and keep it short to reduce mosquitoes seeking shelter around your home.

– Apply a residual surface spray (containing bifenthrin) to outdoor walls, patios, and other spots where mosquitoes might land – this will kill them.

– You can buy these products from hardware stores.

– Remove water holding containers from around the home and garden to ensure mosquitoes do not breed in the backyard.

– Check 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 lanterns.

MVE is a nationally notifiable disease.

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