Japanese encephalitis confirmed in SA, suspected human cases

The disease had previously been detected in Qld, NSW and Vic, earlier this week, with this the first time it has been discovered in southern states.

SA chief veterinarian Mary Carr said PIRSA had been working with producers and private veterinarians in testing, with one confirmed site so far.

PIRSA has not released where the confirmed case is located, with Dr Carr saying it was important for producers across the state to be on alert.

"It is likely to be everywhere, so we want everyone to take all mosquito measures," she said.

JE is transported via mosquitos and waterbirds, and could be present anywhere that mosquitos or waterbirds were present.

The disease is also transmissible to humans, with SA Health investigating 10 cases of acute encephalitis from the past month, with four suspected to be linked to JE.

"All of these people required hospitalisation, with seven people currently still in hospital, and one person who had acute encephalitis, has sadly passed away," an SA Health statement said.

"There has never been a case of locally acquired Japanese encephalitis confirmed in SA, which is why it is essential that we all take extra precautions against mosquitoes and continue to 'fight the bite'."

SA Health recommendations include preventing mosquito bites by covering up with long, loose fitting and light coloured clothing.

Mosquitos can bite through tight clothing, such as jeans.

Mosquitos should be prevented from coming inside, and anyone outside should apply an insect repellent containing DEET or picaridin.

"Simple changes around the home can help to reduce and eliminate mosquitoes, such as cleaning up water around the house to prevent breeding, and installing mosquito-proof mesh on doors and windows," the statement said.

"It is important that people remain vigilant in protecting themselves against mosquito bites particularly during periods of warmer weather when mosquito activity is high."

Most people infected will be asymptomatic or just have mild febrile symptoms, but a small proportion develop encephalitis, which may be fatal or cause long-term neurological damage.

Symptoms of encephalitis may include confusion, headaches, neck stiffness, tremors, drowsiness and seizures.

While just detected this week, Dr Carr said there was a chance the disease had been in SA for some time and this was just the first signs of it.

She said the "wet, warm balmy nights" and weather patterns this season were perfect breeding conditions for mosquitos, which could help the disease to spread.

"We would expect, in a temperate climate like SA, to have a push for the next two months and then to die off," she said.

"There is a chance it could be something we need to be dealing with next year and the year after."

Dr Carr said the signs pig producers should be looking for are reproductive failure, such as with stillborn piglets, or piglets with neurological signs like paddling, tremors or convulsions.

JE is a notifiable disease and any suspected cases should be reported to private veterinarians or through the Emergency Animal Disease Watch Hotline on 1800 675 888.

Dr Carr said the disease in pigs would result in a production hit to producers, with the loss of piglets, but said the sows could be retained in the herds.

"Sows normally recover with no ill-effects, and it is thought to get a lifelong immunity," she said.

"This is not a disease where destruction is needed."

Dr Carr stressed that there was no food safety issues with SA pork products and they were still safe to consume.

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Horse owners are also warned to be on alert for cases in horses.

Symptoms include elevated temperatures, lethargic behaviour or hanging of heads and neurological signs. If spotted, these should be reported to a veterinarian or PIRSA.

There have been no confirmed cases of JE in horses in Australia.

Dr Carr said the disease was in a similar family to West Nile virus or Murray Valley encephalitis, which were also mosquito-borne diseases.

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