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  • Rikki Lambert

Victorian cases Japanese encephalitis' first transmission to humans in southern Australia

Updated: Mar 5, 2022


Agriculture departments began warning in late February of a JEV outbreak in pigs at Echuca and other locations in New South Wales and health authorities have now confirmed an unprecedented transmission of the virus to humans in southern Australia.


Four Victorians have contracted the Japanese encephalitis virus, at least one of which has since been discharged.


Victorian health officials issued a warning about the disease on Sunday 27 February. 'JEV' spreads through mosquito bites and people in regional areas who are in contact with pigs may be at particular risk.


The disease is not transmitted from person to person and cannot be caught by eating pork or pig products.


Australia's health department confirmed the disease had been found in one piggery in Victoria's north, six piggeries in NSW and one in Queensland. Australian Chief Veterinary Officer Dr Mark Schipp said:

"This is the first time the virus has been detected in southern Australia, and biosecurity authorities are working with their human health departments to understand the implications and risks of human exposure." 

Federal, state and territory authorities are meeting regularly to "work through the next steps of this situation".


On Friday afternoon Dr Mark Schipp confirmed JEV had been detected at 14 piggeries across NSW, SA, Queensland and Victoria.


Anyone who works with pigs or horses, even if they're backyard pets, has been urged to keep an eye out and report any possible signs of the disease.


Australia's Acting Chief Medical Officer Sonya Bennett said two vaccinations were available for protection against JEV in Australia, whilst a Sapporo research team has revealed a skin patch to administer the vaccine at one-tenth the dosage of subcutaneous injection for the same efficacy.

A Sapporo-developed skin patch to administer JE vaccine effectively at one-tenth the dosage, revealed in January

Older people and those aged under five who are infected have a higher risk of developing a serious illness.

"Encephalitis is the most serious clinical consequence of JEV infection. Illness usually begins with symptoms such as sudden onset of fever, headache and vomiting," she said.

Dr Bennett said anyone experiencing these symptoms should seek urgent medical attention.


She encouraged people to avoid exposure to infected mosquitoes, with those in high mosquito areas encouraged to use repellent and cover up with loose-fitting clothing. 


Recent wet weather during the southern summer due to the La Nina weather cycle has created ideal breeding conditions for mosquitoes, with authorities previously warning of the potential transmission of Rufus River virus along southern inland waterways.


A recent SA Health alert generally on mosquito-borne encephalitis


South Australia's agriculture department, PIRSA, issued a JE warning on Monday for pig farmers, saying the most common clinical signs in pigs are mummified and stillborn or weak piglets, some with neurological signs.


PIRSA advised that many cases in horses are asymptomatic, meaning that they can be infected but not show signs of the disease. Neurological signs are similar to other flavivruses such as West Nile Virus. These may include fever, jaundice, decreased or no appetite, lethargy.


A Chief Veterinary Officer Notice has been issued directly to veterinarians and other key stakeholders as agricultural and health state agencies collaborate nationwide to undertake environmental surveillance to understand the implications and risks of human exposure.


SA Chief Veterinary Officer, Dr Mary Carr, said farmers and veterinarians should remain vigilant for signs of Japanese Encephalitis and should report any concerns to the Emergency Animal Disease Hotline on 1800 675 888.


On Friday, the CVO and acting CMO issued a joint statement as they declared the unfolding situation in Australia concerning the Japanese encephalitis virus (JEV) a Communicable Disease Incident of National Significance.

“A national working group of communicable disease, vaccine and arbovirus experts has been established to support the response, including mosquito surveillance and control measures and identification of those at direct risk, and for the rollout of vaccines. Public health communications regarding mosquito protection will target affected communities.
“The Australian Government’s health and agriculture departments are working very closely with their state government counterparts to ensure a swift and coordinated response.”
"Pigs are the focus from a human health perspective as they can infect mosquitoes that can then infect humans. This is not the case with horses. Humans can become infected with JEV through the bite of an infected mosquito. The virus cannot be transmitted between humans, and it cannot be caught through eating pork or pig products.
"Less than 1 per cent of people infected may develop a serious illness such as encephalitis and experience symptoms including neck stiffness, severe headache and coma, and more rarely, permanent neurological complications or death. The vast majority of infected people will show mild or no symptoms at all.

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