A man in the far north of South Australia has been diagnosed with Murray Valley encephalitis virus.

According to the Department of Health Communicable Diseases Control Branch there have also been four confirmed cases in the Northern Territory and four in Western Australia since late last month.

The Murray Valley encephalitis virus is transmitted by infected mosquitoes.

The disease can be prevented by avoiding mosquito bites. Travellers to the north of the state are advised that mosquito bites may be prevented by:

• Covering up with long, loose clothing of sufficient thickness to prevent mosquitoes biting through the fabric
• Avoiding exposure outdoors when mosquitoes are most active (dusk and dawn)
• Using repellent on exposed skin (the most effective repellents contain 5-20 percent di-ethyl-N-toluamide or DEET)
• Using flyscreens in accommodation and mosquito nets where there are no flyscreens (especially for babies).

This is particularly important when camping out, as repellents are only effective for around four hours.