The wife of a man fighting for his life in a Melbourne hospital is urging others to be aware of the early signs of the mosquito-borne virus that took weeks to diagnose.
Jackie Monk told ABC's 7.30 in an interview that her husband contracted Japanese encephalitis in their hometown of Corowa on the New South Wales-Victorian border in mid-February.
He is now in a critical condition with "a very severe form of the virus".
Japanese encephalitis virus (JEV) is spread to humans and other animals via mosquitoes, and while 99 per cent of people who contract the virus do not become unwell, those who develop symptoms face up to a 30 per cent chance of dying, according to the World Health Organization.
"This emergence of Japanese encephalitis virus is a real, new, and concerning development," said Associate Professor Phillip Britton from Sydney University.
Dr Britton has spent years studying Japanese encephalitis, which is prevalent in parts of South-East Asia but rarely seen in mainland Australia.
"There have been occasional detections of the virus in mosquitoes or pigs in far northern Australia, but it's really been a rare occurrence up there, and certainly not been an issue in other parts of Australia," he told 7.30.
"So when it was detected in pigs in south-eastern Australia, that was a major new development."
The virus was first detected in piggeries and has now spread to 21 different facilities in New South Wales, Victoria, Queensland, and South Australia.
It has infected 10 humans, and two men have died from the virus.
Dr Britton told 7.30 that while JEV could be deadly, the chances of becoming ill with the virus were low.
"Most people who get infected from a mosquito actually don't become very unwell [and] might not get any symptoms," he said.
"But about something in the order of one in 100 people infected, this virus goes to the brain or spinal cord.
'The man that we know and love isn't there anymore'
Sitting in a Melbourne hotel room preparing to visit her husband David Kiefel in hospital, Jackie Monk is looking at photographs of the couple.
"He's such a good man," she said.
"He is such a wonderful husband. And a great friend to many … he's the kind of person you can talk to with no judgement; people can tell him anything about their life."
After recovering from an 18-month battle with stage 4 oesophageal cancer and with the pandemic and restrictions easing, 2022 was shaping up to be a good year for Mr Kiefel.
"Everything was good, everything was great … we're cancer-free. Life can go on," Ms Monk told 7.30.
The couple were excited to travel again and enjoy life.
"And then, two weeks later, David collapsed with God knows what," Ms Monk said.
On February 16, David Kiefel started to feel unwell and his condition soon deteriorated.
"David had achy joints. He said he had a low-grade headache," Ms Monk said.
Mr Kiefel was airlifted to The Alfred Hospital in Melbourne in late February, where Ms Monk has told 7.30 he is currently on life support, and his condition has deteriorated further.
Ms Monk lives with a chronic illness and Mr Kiefel is her full-time carer.
"I can't at the moment think about life moving forward," Ms Monk said.
She told 7.30 she would be faced with very difficult choices over the coming days as the virus had now caused brain and spinal cord damage to her husband.
"I don't think he has any idea of where he is or what is going on. I don't think he knew who I was.
"The man that we know and love isn't there anymore."
Recent weather conditions caused 'a domino effect'
In the town of Corowa where Mr Kiefel and Ms Monk live, recent rains and floods have led to a surge in mosquito numbers.
The town is also next to a piggery where the rare virus has been detected, however, they do not know where Mr Kiefel contracted JEV.
The company that runs the piggery declined to comment, however, a spokesperson for the Australian pork industry told 7.30: '"Industry has been working closely with governments to prioritise the safety of staff and the welfare of the animals.
Associate Professor Cameron Webb, a medical entomologist from NSW Health Pathology, has been studying JEV in mosquitoes.
"The virus circulates between mosquitoes and waterbirds," he told 7.30.
"But occasionally those infected mosquitoes will either bite pigs or sometimes people.
"The conditions over the last couple of years — a weather pattern dominated by La Nina, with considerable rainfall — have created ideal conditions for the emergence and spread of Japanese encephalitis virus.
"The water provides habitat for the birds that are a reservoir of the virus, and the mosquitoes that spread it from the birds to pigs and potentially the people."
Dr Webb said work was underway to determine how the virus spread into mainland Australia, but recent weather conditions were likely to blame.
"We're still not sure how the virus made its way to mainland Australia," he told 7.30.
"But research that's been conducted in northern Australia shows that infected birds, and sometimes even windblown infected mosquitoes, can be a pathway of introduction of viruses into northern Australia.
"Once they get here, if conditions are suitable, you get a domino effect of infected waterbirds and mosquitoes spreading the virus in southern areas of Australia."
Dr Webb said the scale of the problem was still unclear, however, he was hopeful the threat would dissipate as the season changed and floodwaters receded.
"As the weather cools here in Australia, mosquito populations will decline, and the risk of transmission will decline with that," he said.
"But we'll also see activity in northern areas of NSW and southern Queensland where mosquito populations are expected to continue for many weeks to come."
A spokesperson for the Agriculture Department told 7.30 JEV was first detected in piggeries at the end of February and testing and tracing was underway, along with mosquito control programs.
They said the culling of pigs was not part of the response plan for the virus.
"The natural host of JEV is waterbirds (herons and egrets), it is transmitted by mosquitoes; both of these groups are in abundance due to the present climatic conditions," the department said.
"Also in abundance are feral pigs, estimated to total over 3 million in Australia. Pigs are the amplifying host for JEV."
'Be aware, but don't be alarmed'
Jackie Monk hopes to raise community awareness of the virus to ensure others don't have to go through her pain.
She is also calling for all residents in affected areas to be offered free JEV vaccines and for measures to be taken to reduce stagnant water after flooding.
A spokesperson for the Health Department told 7.30 vaccinations were part of the response to the virus and people in affected regions with "direct exposure or close proximity to pigs and mosquitoes and high-level occupational exposures" would be offered vaccines as an initial priority.
The department added: "It is important to understand that vaccination will protect the individual against disease, but has no effect against spread and transmission of the virus, as JEV is not transmitted from humans to other humans or mosquitoes."
"Therefore the total number of people vaccinated as a proportion of those identified as at-risk does not have an impact on the population more broadly.
"It is estimated that there are currently sufficient supplies of JE vaccines in Australia to vaccinate the initial priority groups."
Dr Philip Britton also urged people to be vigilant, and said the most effective action was preventing mosquito bites with protective clothing, mosquito repellent, and mosquito nets.
"We get blasé about mosquitoes in Australia, we're used to them every summer," he said.
"But right now … we're really encouraging people to be super vigilant about how they use insect repellent, how they go out into the kinds of places where mosquitoes are prevalent, in camping and fishing and other sorts of activities.
Dr Britton said anyone with symptoms like fever, headache, confusion or seizures should see a doctor, especially if they have been exposed to mosquitoes in at-risk areas, "particularly in sort of the band from the Murray River towns in northern Victoria and southern NSW through to Queensland in that kind of agricultural band".
Watch this story on 7.30 tonight on ABC TV and ABC iview