SYDNEY, Nov. 23 (Xinhua) -- Authorities of Australia's state of New South Wales (NSW) on Wednesday warned its residents to be alert for Japanese encephalitis as the state is experiencing an extended period of wet weather.

The government urged livestock owners to watch for signs of this infectious disease as routine surveillance indicated the virus remains present in parts of regional NSW.

The state's Minister for Agriculture and Western NSW Dugald Saunders said mosquito numbers are expected to rise in the coming weeks, given the extended periods of wet weather across the state.

"As we recover from high rainfall and head into warmer temperatures, the conditions are ideal for Japanese encephalitis to spread," he said.

Japanese encephalitis is caused by the Japanese encephalitis virus (JEV). It is spread through mosquito bites and is more common in areas of increased mosquito activity.

Saunders said the disease won't pose a food safety risk, but it could cause reproductive failures in pigs, with 50-70 percent losses reported in previously affected populations.

"We're encouraging farmers to be on high alert for ill livestock, with clinical signs of infection including a high temperature, jaundice, lethargy, anorexia and neurological signs including incoordination and impaired vision," he added.

Japanese encephalitis infections in humans are most commonly asymptomatic, but on rare occasions, they can result in severe disease and even death.

NSW Minister for Health Brad Hazzard also warned residents who live or frequently work in areas identified as having the disease to take precautions such as vaccines and wearing long-sleeved clothing to prevent mosquito bites.

The state is providing free JEV vaccines to those aged 2 months or older who live or routinely work in areas of high JEV concern or at higher risk of exposure to mosquitoes.

Since it was first detected in Australia in 1995, human cases of JEV acquired in Australia have been very rare, but in 2022, the number has increased, with human cases identified across several states. As of Oct. 19 this year, 42 cases of JEV infections have been notified in Australia since Jan. 1, 2021.