SYDNEY, Aug. 18 (Xinhua) -- Researchers from the Menzies School of Health Research have investigated an early case of Japanese encephalitis virus (JEV) from early 2021, which could provide clues into how the virus has spread into Australia, and what prevalence will be into the future.
The case study, published in the New England Journal of Medicine on Thursday, was a report on a "sentinel case" in a 45-year-old resident of the Tiwi islands, a group of islands belonging to Australia and 80 kilometers off the mainland's northern coast.
Lead author on the project and Director of Tropical and Emerging Infectious Diseases at Menzies School of Health Research, Professor Bart Currie, told Xinhua on Thursday that by zooming in on a singular initial case it allows epidemiologists to reverse engineer how an outbreak occurs.
"So, by recognizing that this case is related to the cases in southern Australia gives us a timeframe, which is very different from what we originally thought back in early 2022," said Currie.
The first cases of JEV in Australia's eastern states of Queensland and New South Wales (NSW) were reported in March 2022. Through genomic sequencing, Currie and his colleagues were able to link the outbreak to this initial case a whole year prior.
Before this, Australia had not had locally acquired cases of JEV since the mid-1990s.
The virus is thought to be brought into Australia by mosquitoes blown by cyclones or migratory birds, before it is amplified in wild and farmed pig populations.
"Sequencing of the virus shows that what has happened is there has been not just this importation of the virus into Northern Australia, but an amplification of that virus in a silent way -- within these explosive outbreaks in the piggeries."
As of Aug. 1, Australia has reported a total of 40 cases and five deaths due to JEV. Currie said while these statistics are dwarfed by COVID-19, it was important to do everything to prevent or prepare for JEV becoming a seasonal virus in Australia.
"So, this is an issue that is going to play out in Australia over the next couple of years if there are further cases of fairly substantial vaccination programs, because this terrible disease is entirely preventable with vaccination."
He added that climate change and the floods in eastern Australia have likely been amplifying factors, which could see JEV become a permanent issue despite the nation being outside the tropical disease's normal range.
Australia is in the fortunate position of being able to look to countries in Asia that have been dealing with JEV for decades.
"There is excellent work done from colleagues over many, many years in Japan, in South Korea, and in China so that informs what we can do. So, we're very fortunate in our understanding of the virus," he said. ■
