• About 99 percent of JEV infections cause no symptoms
  • Those who do get sick experience mild, cold-like symptoms
  • However, in serious cases it can cause your brain to swell

A man in his 60s in Australia has reportedly died from Japanese encephalitis, a mosquito-borne virus.

Health officials in the country said they were investigating the case to find out how he became infected. The health department in the state of Victoria said an autopsy confirmed the man's cause of death. This was the first death to be reported in the country, while the state confirmed seven cases of the virus.

The Japanese encephalitis virus (JEV) spreads via mosquitoes, which carry it from either pigs or water birds.

The number of piggeries with confirmed cases had increased from 14 on Friday to 21 by Monday in the country, according to The JEV has been discovered in more than 40 piggeries across Victoria, New South Wales, Queensland and South Australia within the past month.

The federal health department Friday declared Japanese encephalitis a communicable disease incident of national significance, according to the Guardian. A Japanese encephalitis vaccine was available, and recommended for people who work with or around pigs. Agriculture Minister David Littleproud was unable to say how many people had been vaccinated.

It was a “matter for the states," Littleproud told Sky News Tuesday, according to The Australian. “We handed them all over and obviously the states have worked through with particularly those working in the piggery industry."

“They’ve been targeting some local communities, but local health authorities are working through that. ... We’re trying to act within both Health and Agriculture to move quickly to get vaccines, but also to make sure that councils are doing work around trying to eradicate mosquitoes in some of those areas where there’s water laying.”

About 99 percent of JEV infections cause no symptoms, and those who do get sick, experience mild, cold-like symptoms. However, in serious cases it can cause your brain to swell, health officials reportedly said.

The most concerning symptoms are severe headache, neck stiffness, fever, sensitivity to light and sound and movement difficulties, as these may indicate a brain inflammation known as encephalitis.

“We’re not going to see thousands of cases, this is not another pandemic,” says infectious disease physician Associate Professor Paul Griffin, according to the Sydney Morning Herald. “But we need to be on our guard. We’re seeing more of these tropical diseases flare up [in Australia] because of climate change.”

Young children and older people have a higher risk of developing more severe illness with JEV, a Victorian government spokeswoman reportedly said.

This is a representational image. Luis Robayo/AFP/GETTY