Victorian health authorities have warned the community around Mildura is at "significant risk" of contracting Murray Valley encephalitis (MVE) in coming weeks, after more virus detections were made in local mosquitoes.
Last week, authorities warned the MVE virus had been detected in mosquitoes in the local government areas of Loddon, Indigo and Mildura.
The virus, which can cause severe brain inflammation in a very small number of infected people, has been recently detected in booming mosquito populations across flood-hit south-eastern Australia.
In an update on Saturday, Victorian health authorities said a "high number" of detections from across northern Victoria were in the Mildura area.
"These results mean that the MVE virus is increasing in the mosquito population and indicate a significant risk to people in these areas, particularly Mildura," a health department alert said.
"The risk of human cases in the coming weeks is very high."
Deputy chief health officer Deborah Friedman said the detections had been increasing "week on week" with "multiple detections coming in thick and fast".
She said Mildura faced a "really concentrated area of risk" and as human cases began to emerge it was important the community was prepared.
"Mosquito bite protection shouldn't just be something that people consider, it has to be something that everybody undertakes to protect themselves," she said.
Anyone with symptoms linked to encephalitis urged not to delay medical help
Dr Friedman said while the majority of people infected with MVE virus would not have symptoms, the small minority who developed a brain infection faced "devastating" outcomes.
"Over 30 per cent of people die and about 30 per cent of people have long-term disability, so the implications are really, really serious although this is a very low-frequency event," she said.
She said while the virus was present in northern Australia, the last human cases in Victoria were in the 1970s, "where we had multiple cases … with high mortality rates".
"So it's been a long time since we've even seen this virus trapped anywhere," Dr Friedman.
"Now that we've had so many detections over a short period of time, this is something that really should raise alarm bells about … the potential risk to humans of infection."
Dr Friedman said anyone developing symptoms linked to encephalitis after a mosquito bite such as neck stiffness, sensitivity to light, nausea and vomiting, should seek medical help immediately.
Event organisers told to consider postponing outdoor events
Residents and visitors to the Mildura region are strongly encouraged to take the following measures to reduce the risk of mosquito bites:
- Wear insect repellent at all times when outdoors
- Wear long, loose-fitting, light-coloured clothing
- Avoid time outdoors at dusk and dawn as much as possible
Dr Friedman also encouraged organisers of events to consider the risk to patrons and try to consider ways to improve safety.
"That might mean relocating events indoors during this high-risk period, potentially postponing them if at all possible or perhaps provision of mosquito repellent to patrons is another option," she said.
"We certainly don't want to tell people that they have to be locked inside their homes, but we're really just trying to prevent illness among people who are spending time outdoors."
She said Mildura Rural City Council was working to kill adult mosquitoes and the larvae that sit in bushes and wetlands.
