Australian health authorities are warning people travelling to Japanese Encephalitis prone areas this Easter to take measures to reduce mosquito exposure, following new research highlighting the risks of infection.
The study published in the Australian and New Zealand Journal of Public Health by researchers from Victoria’s state health department estimate 1 in 100 infected people will develop the encephalitis illness. Among those, death could be expected in 20-30 percent of cases, while chronic neurological disability could occur in up to half.
This is partly due to populations in south-eastern Australia having little prior exposure to the disease.
While infection and mortality are uncommon, the study’s co-author and deputy chief health officer for Victoria, Dr Deborah Friedman, warns testing in regions of Victoria’s outbreak show a larger proportion of positive cases occurring.
Rain (and roos) help the spread of mosquito-borne illnesses in Australia’s south
“It is a rare but very serious health concern,” Friedman says.
“It’s also a timely reminder that mosquito borne diseases are circulating in Victoria and other parts of Australia. Testing in Northern Victoria shows that approximately three percent of people in affected areas where mosquitoes carry the disease have been infected – a much larger proportion of people than the number of reported cases of illness.”
Japanese Encephalitis emerged in south-eastern Australia in 2022, having only previously been detected in far north Queensland in the 1990s. Outbreaks of JE along the Murray River along with other mosquito-borne disease like Ross River and Barmah Forest have alert status in Victoria, New South Wales and South Australia.
Since 2021, 45 cases of Japanese Encephalitis had been confirmed across Australia, including seven deaths.
In January, the federal health department revised its case definition to allow reporting of probable as well as laboratory-confirmed cases.
While most JE cases are asymptomatic, symptoms such as sudden fever, headaches and vomiting after potential exposure should be followed up with immediate medical assistance.
Heath authorities recommend vaccination against the virus, and preventative measures such as insect repellents, long and loose-fitting clothing and avoiding exposure at times of high mosquito activity to reduce the risk of infection.
NSW, Vic and SA currently provide free vaccination against the Japanese Encephalitis virus to at risk people in council areas of most concern.