In a follow-up on the unfolding situation in Australia concerning the Japanese encephalitis virus (JEV), the Australia Department of Health has now reported 34 human cases of JEV in Australia as of March 31.
24 have been confirmed with definitive laboratory evidence: New South Wales (10), Queensland (2), South Australia (3) and Victoria (9).
10 are probable cases where the person has been linked epidemiologically and/or has symptoms of the disease and has laboratory suggestive evidence: Queensland (2), South Australia (5), Victoria (2) and NSW (1).
Three fatalities have been report- One in New South Wales, one in South Australia and one in Victoria.
On 4 March 2022, Australia’s Acting Chief Medical Officer, Dr Sonya Bennett, declared the Japanese encephalitis virus (JEV) situation a Communicable Disease Incident of National Significance.
It is not known how the virus came onto mainland Australia, and it’s the first time the virus has been detected in southern Australia. The movement of infected mosquitoes or migratory waterbirds may have played a part in the virus’ spread, officials note.
In February 2022, Japanese encephalitis was detected and confirmed in piggeries in Victoria, Queensland and New South Wales. On 4 March, cases were detected in South Australia. There are currently more than 50 infected piggeries across the four states.
On 30 March, one alpaca in the Adelaide Plains local government area was confirmed with the disease. Alpaca’s, like horses, are considered a dead-end host.
Also in March, the Northern Territory Government confirmed that a feral pig from the West Daly area was positive for Japanese encephalitis. The pig was tested in mid-March as part of a routine animal health survey conducted by the Northern Australia Quarantine Strategy.
Japanese encephalitis is a viral zoonotic disease that is spread by mosquitoes. The virus can cause reproductive losses and encephalitis in pigs and horses. In rare cases, Japanese encephalitis can cause disease in people. People and horses are considered ‘dead end’ hosts. Once infected, they do not play a role in transmitting the virus. Pigs and some species of wild birds are amplifying hosts.
A national working group of communicable disease, vaccine and arbovirus experts has been established.
The working group will support Australia’s response to the JEV situation. This will include:
- mosquito surveillance and control measures
- identification of those at direct risk, and for the rollout of vaccines.
Public health communications regarding mosquito protection will target affected communities.