The South Australian government has expanded the eligibility criteria for the Japanese encephalitis virus (JEV) vaccine as floodwaters continue to provide the perfect breeding grounds for mosquitoes.
South Australia's Chief Public Health Officer Nicola Spurrier said all residents in the Riverland and Murraylands would now be eligible for the free JEV vaccine.
"It's about 77,000 people [eligible] now [and it's being] opened up to approximately 100,000 residents," she said.
Initially the vaccine was only available to people who worked in the area's piggeries, which were considered high-risk locations.
That was then expanded to include people who lived within five kilometres of the River Murray, but visitors to the area were deemed ineligible.
Earlier on Monday, Opposition Health Spokeswoman Ashton Hurn called on the state government to investigate claims there were unused JEV vaccines available in New South Wales.
Ms Hurn said family and friends of residents in flood-impacted areas were facing a cost of $300 for the vaccine to protect themselves.
"Now that the emergency management declaration for the floods has ended, every South Australian should be given the choice to protect themselves from JEV," she said.
"[Premier] Peter Malinauskas knew the emergency declaration would end, so it's quite disappointing he was flat-footed in speaking to other states about additional JEV supplies.
"To better protect the community and help ease the pressure on our already overworked health system, free JEV vaccines make a lot of sense."
Professor Spurrier said she had been monitoring vaccine supplies.
"I do talk regularly with the chief health officers in other states," she said.
"I've spoken before Christmas to WA and ACT, looking at states where they haven't had any JEV cases.
"We are also talking to New South Wales … [which doesn't] have a large surplus either but we are talking to them just about whether there is any way to bring forward any of our doses here in case we need them."
"We work together as chief health officers nationally, as a team, to make sure that we can cover the most at-risk people in our state.
"We are getting ongoing supplies every month coming in now of that life-saving vaccine."
The eligibility criteria includes being outdoors for at least four hours.
Mr Malinauskas said the government was "constantly assessing various supplies of the vaccine" for JEV.
"We are committed to rolling it out as best as we possibly can, particularly given the flooding situation in and around the Murray region," he said.
MVEV detected in chickens
On Friday, the first case of Murray Valley encephalitis virus (MVEV) was detected in a sentinel chicken from a surveillance flock based in Clare, north of Adelaide.
It was the first time the potentially deadly virus has been found outside of the River Murray region.
In a statement, an SA Health spokesperson said while there had been no cases of MVEV reported in humans since 2011, the findings confirmed that local mosquitoes carried and could transmit the virus, meaning there was a risk for it to be passed on to humans.
They said signage would be installed in high-risk places to warn the public.
In addition to JEV and MVEV, mosquitoes can also infect humans with Ross River virus, Kunjin virus and Barmah Forest virus.
"I think this is just an important message to all South Australians, that no matter where you live in our state, we should all be trying to protect ourselves from mosquitoes this year because of the risk of catching a virus from a mosquito bite," Professor Spurrier said.
Health authorities recommend wearing long, loose-fitting and light-coloured clothing, and applying insect repellent on exposed skin.
"It's not enough to put a dab here, a dab there or wear a little mosquito bracelet because you actually have to cover all of your skin the same way we put on sunblock," Professor Spurrier said.
