Despite new detections of Japanese encephalitis virus in feral pigs interstate, there has been no new detections in piggeries in SA since May, according to a PIRSA spokesperson.
They said the risk of transmission of the virus in SA was considered low due to the cold weather resulting in minimal mosquito activity.
"There are also no movement restrictions currently in place on any pigs in SA associated with JEV," they said.
"The last identified case aligns with infection in March.
"As the disease had now occurred across four states and with some of the SA detections to-date occurring in locations away from the River Murray, producers, regardless of their location, should remain vigilant for signs against the disease and protect themselves and their animals from mosquito bites.
"While the JE risk is currently low, the risk is likely to increase from spring, as temperatures and mosquito activity start to increase."
About 70 piggeries in SA, Vic, NSW and Qld were isolated after the surprise outbreak earlier in the year.
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There are 39 human cases in Australia - SA 5, NSW 13, Qld 2 and Vic 9, while up to five people are believed to have died from the virus.
JEV has been linked to at least 26 probable cases in horses in NSW.
PIRSA has not detected any cases in horses in SA, but a case was discovered in an alpaca in the Adelaide Plains.
"It is believed that alpacas, like horses, are a 'dead end host', meaning they do not carry enough virus in the blood to re-infect mosquitoes," they said.
PIRSA said the incident posed no additional risk of further infection to other animals or humans.
Biosecurity officials say the arrival of the cold, winter weather had helped slow the movement of mosquitoes which have spread the virus.
"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 federal government said.
"It is likely that the movement of infected mosquitoes or migratory waterbirds may have played a part in the virus' spread."
Most human infections of JEV cause no symptoms or mild symptoms such as headache or fever.
A person with severe disease may present with inflammation of the brain (encephalitis), characterised by sudden onset of vomiting, high fever and chills, severe headache, sensitivity to light, neck stiffness and nausea/vomiting.
Children aged under five years of age and older people who are infected with JEV are at a higher risk of developing more severe illness.
There is no risk to humans from consuming pork or pig products.
Now JEV is part of Australia's virus landscape, the return of warmer weather in spring is also expected to bring a fresh series of warnings about protecting yourself while outdoors.
Researchers have found the virus has already escaped into the wild, infecting feral pigs, so the virus is officially here to stay and cannot be eradicated.