A rare and potentially life-threatening virus has been detected in Victoria for the first time in more than a decade.

Murray Valley encephalitis has been detected in a mosquito in Mildura this month as part of a routine monitoring program.

At the weekend the Department of Health said detections had increased in the state’s north and there’s now a “significant risk” posed.

The virus causes fever, headache, nausea, vomiting and aches and can cause severe brain inflammation in rare cases.