There have now been three confirmed deaths from the Japanese encephalitis outbreak.
Those fatalities from the mosquito-borne JEV outbreak are in Victoria, New South Wales and South Australia but authorities warn testing for the virus is complex and takes time.
JEV has been confirmed in more than 20 commercial piggeries in NSW, Queensland, Victoria and South Australia.
There are eight confirmed cases of JEV in NSW - Murrumbidgee (5 and the fatality), Far West (1) and southern NSW (1).
Confirmed cases are related to Balranald, Berrigan, Federation, Goulburn Mulwaree, Griffith, Temora and Wentworth.
There are also eight cases in South Australia.
Test results have confirmed SA's death which had previously been blamed on an unknown encephalitis was now JEV.
Another piggery in Victoria has joined the outbreak as well, to now total 12.
Those piggeries are in the Wangaratta, Moira, Greater Shepparton, Campaspe, Gannawarra, Loddon, Greater Bendigo and Northern Grampians council areas.
Agriculture Victoria says it is providing "advice and information to farmers, livestock and horse owners".
A public health alert has also been issued in Queensland with just one human case confirmed and two piggeries with confirmed infections.
Government authorities there warn recent flooding will likely increase the numbers of mosquitoes.
MORE READING: Outbreak puts focus on biosecurity.
These increased detections are the result of national surveillance efforts to identify new cases and determine the extent and spread of the disease.
Authorities are working with both the pig and horse industries in response to the disease.
Infection is not spread directly from pigs to people, and there is no risk to humans from eating pig meat.
Pigs are known to "amplify" the disease while horses are often infected, but as said to be a dead-end host.
JEV vaccines are recommended for people at a higher risk of exposure to the virus, such as those working with pigs.
The federal government is spending $69 million on vaccines and mosquito management systems.
Urgent vaccinations are being supplied from the national stockpile of about 15,000 doses.
The government will spend almost $30 million buying more vaccines from across the world - enough for an extra 130,000 doses.
Health Minister Greg Hunt said those new vaccines would likely be secured over the next month.
Less than one per cent of people infected with JEV will experience symptoms.
Some infected people experience an illness with fever and headache.
People with severe infection may experience - neck stiffness, disorientation, tremors, coma, seizures.
If you have any of these symptoms please seek medical treatment.
Animal Medicines Australia, the peak body representing veterinary medicines and animal health, said while the immediate focus was rightly on human health impacts, authorities should not overlook the serious impact JEV also has on animal health and welfare.
AMA executive director Ben Stapley said JEV highlights the fact human and animal health are intrinsically linked.
Mr Stapley says there was no animal vaccine for JEV registered in Australia although they are available elsewhere.
"In South East Asia where JEV is endemic, a preventative vaccine is used in pig populations at the start of the mosquito season to slow the spread of the virus and reduce the risk to human populations where human and pig populations have a significant interface," he said.
"It also reduces production losses in pig populations. By protecting the health of animals, we are simultaneously protecting people from zoonotic diseases."
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