There are many more cases today of Japanese encephalitis as a national response to the surprise virus outbreak gathers pace.
The number of suspected cases in Victoria has grown to eight, which includes two children, with six in hospital.
Encephalitis cases in South Australia now number nine with one fatality. All are being investigated whether they are the Japanese variant.
A Queensland woman in her 60s is in a critical condition in hospital after contracting the mosquito-borne disease while on a campervan trip.
Several other cases of encephalitis of unknown origin are being investigated..
NSW Health said it had one "highly probable" case from the NSW-Victoria border region in ICU in a stable condition.
Communities right around mainland Australia have been warned about the spreading danger.
More cases of the virus are expected to be confirmed in coming weeks.
Authorities have now confirmed outbreaks at 14 piggeries across South Australia, NSW,, Queensland and Victoria.
Japanese encephalitis was on Friday declared a communicable disease incident of national significance.
Australia's acting chief medical officer Dr Sonya Bennett said the unfolding situation required a national approach to coordinate health policy, interventions and public warnings.
Experts now believe the virus swept across Australia several weeks ago from the Torres Strait.
"The movement of infected mosquitoes or migratory waterbirds may have played a part in the virus' spread," government officials said.
Now it is in, it cannot be stopped.
The virus is primarily spread by mosquitoes.
It is not spread from pigs to people, or from pig to pig.
Pigs and horses are most at risk, the emerging cases of infections among humans are considered rare but can be fatal.
While the pig industry was braced for the arrival of African Swine Fever which has been subject to a major campaign to stop its spread from the north, Japanese encephalitis has come as a shock.
The pig industry is working with health authorities to trap mosquitoes and control outbreaks at those piggeries where the infection has already been confirmed.
Movement restrictions have also been applied to infected pig properties.
Authorities have so far decided large-scale culling of infected pig herds is unnecessary.
"Given the abundance of feral pigs (amplifying hosts) and waterbirds (natural reservoir hosts) in these areas it is not believed that culling infected pigs would serve any purpose," a spokesman for the Federal Agriculture Department said yesterday.
The virus, or JEV, is now considered endemic in Australia.
"Attention is being given to reducing mosquito numbers and preventing infection of pigs, horses and humans."
A national surveillance plan is being implemented which looks to identify and locate infected mosquitos, birds, pigs (including feral pigs), horses and humans.
Pig producers have been told to "be highly vigilant" for signs of the encephalitis and report unexpected abortions or stillbirths.
There is no risk to humans from eating infected animals.
It cannot be caught through eating pork or pig products. The disease is not transmitted from person to person.
A national working group of communicable disease, vaccine and arbovirus experts has been established to support the response, including mosquito surveillance and control measures and identification of those at direct risk, and for the rollout of vaccines.
There are no treatments for encephalitis but there are vaccines available to try and prevent infection.
Work is being done to ensure adequate supplies of the two vaccines used with JEV are readily available across Australia.
"The Government will work closely with the states and territories to support the distribution of vaccine doses to at-risk population groups," a government spokeswoman said.
"People working with pigs, even if they're only a backyard pet or a small herd, should take steps to control mosquitoes, as well as continuing to practice good biosecurity," the spokeswoman said.
The authorities have clearly identified piggery workers as a target for vaccines but messaging also includes "people who work with animals in Australia".
It is unlikely vaccination will become mandatory.
"The Australian Government's health and agriculture departments are working very closely with their state government counterparts to ensure a swift and coordinated response," the government spokesman said.
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Severe illness arising from JEV infection in humans is rare and most people will have no symptoms at all if infected.
However some may develop a serious illness such as encephalitis and experience symptoms including neck stiffness, severe headache and coma, and more rarely, permanent neurological complications or death.
Encephalitis is the most serious clinical consequence of JEV infection. Illness usually begins with symptoms such as sudden onset of fever, headache and vomiting.
"Anyone experiencing these symptoms, particularly if they've visited regions in eastern Australia or South Australia where there has been high mosquito activity, should seek urgent medical attention," government health authorities warn.
People have again been warned to try and prevent mosquito bites by using mosquito repellent containing picaridin, DEET or oil of lemon eucalyptus on all exposed skin and reapply every few hours.
Wear long, light coloured and loose-fitting clothing as well as covered footwear when outside. Ensure accommodation, including tents, are properly fitted with mosquito nettings or screens.
To report suspected JEV in pigs or other animals, contact your local veterinarian or call the national Emergency Animal Disease Watch Hotline on 1800 675 888.
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