Japanese Encephalitis Virus Has Been Detected in Australia — Here’s What You Need to Know

japanese encephalitis virus

If you had ‘more virus’ on your 2022 bingo card, you would be correct — but not for the reason you might think.

While COVID appears to be slowing to an almost ignorable level around the globe (at least, for the time being), a new threat has emerged in the form of yet another animal virus.

Japanese encephalitis virus, or JEV, is a mosquito-borne virus that causes the condition known as encephalitis. This is a neurological infection that results in a swelling of the brain. Symptoms are normally mild, however, in some rare cases, they can lead to death.

The virus, which is normally an equatorial virus, has been detected in Australia for the first time in over two decades.

So far, there have been nine confirmed cases in four states, with many more under investigation as authorities warn that the floods are likely to bring about a spate of new infections.

A man in his 60s from northern Victoria was confirmed to have died from the disease on February 28.

Australia’s Acting Chief Medical Officer, Dr Sonya Bennett, declared the virus a “Communicable Disease Incident of National Significance” on Friday last week. A vaccine rollout, which thankfully we already have for this virus, has been authorised for those who are most at risk of catching it.

Here’s what you need to know about the unfolding outbreak.

What Is Japanese Encephalitis Virus?

JEV is the virus that causes Japanese Encephalitis. Encephalitis simply means inflammation of the brain, which is often caused by a viral or bacterial infection, and the ‘Japanese’ part is because it was first described in Japan in 1871.

The virus is common throughout much of South-East Asia and the Western Pacific region of the world where roughly 3 billion people live. Each year, the WHO records around 70,000 symptomatic cases, with around 17,000 deaths.

Because the virus is carried by animals like pigs, horses, and birds, and is spread by mosquitos to humans, JE outbreaks often come in waves every few years, particularly after heavy rainfall, like what we’ve been experiencing here.

999% of people who catch the virus show no symptoms. For the 1% who do, only 0.4% of those will need clinical care, meaning that it very rarely leads to death. There is however no specific treatment for the virus and around a third of those who recover appear to have persistent cognitive issues. Symptoms include mild flu-like symptoms and in severe cases can include high fever, headache, neck stiffness, disorientation, and seizures.

ABC Sports broadcaster Karen Tighe had encephalitis in March 2020. She describes the illness as beginning with a loss of appetite progressing to her feeling “very off” and needing to lie down after six days. She said she couldn’t remember her own address or birth date and, two years later, still struggles with memory loss.

Where Is Japenese Encephalitis Spreading?

Japanese encephalitis virus is normally confined to Torres Strait Island within the Australian territory. Limited outbreaks have occurred in the Northern Territory and Northern Queensland but they are incredibly rare.

Agriculture Minister, David Littleproud, told the ABC’s Radio National on Monday that climate change and extreme weather has played a role in its spread to the mainland.

Migratory waterbirds, which are typical sources of the virus, travelling to newly wet and warm areas are thought to have promoted its spread. Mosquitos passing the virus between them and farm animals and then onto humans is the main source of transmission.

“The fact that it has effectively spread right across the eastern seaboard into South Australia says that this is a real threat that we need to take seriously,” Littleproud said.

JEV has been confirmed in pigs in Victoria, New South Wales, Queensland, and South Australia. However, the disease can only pass through blood-to-blood contact and there is no risk in eating pork.

Victorian health officials issued a warning about the disease on 28 February after evidence was found in pigs in Echuca while Queensland officials confirmed a case in their state on 3 March.

Two people are currently being treated in hospital in NSW for the disease along with five others in Victoria, with dozens more under investigation, four of whom are in South Australia. Experts have said that people in the regions affected need to keep a close watch for symptoms of the disease, particularly if they live near farms.

Australia’s Chief Veterinary Officer Mark Schipp says animals at more than 42 piggeries across the country have been infected and that farmers, including hobbyists and those who keep pigs as pets, need to be on the lookout for signs of the disease.

“The key signs to look out for in pigs are stillborn or weak piglets, some with an impaired nervous system. Piglets can develop encephalitis or wasting, depression or hindlimb paralysis. Adult sows do not typically show signs of disease,” Schipp said.

If you suspect an animal is showing signs of the disease, you must report it via your local veterinarian or the national Emergency Animal Disease Watch Hotline on 1800 675 888.

While we can work to eradicate the virus, the concern is that it could easily spread to the wild pig population, of which Australia has a lot. If that happens, the virus could be quite tricky to get rid of.

What Do We Do About It?

We already have two effective vaccines for JEV and the government has said that it is already coordinating an effort to vaccinate people who are at high risk of catching the disease. A further shipment of JEV vaccines to Australia is being arranged.

Outside of vaccination, experts are saying that prevention is the best strategy for mitigation.

This means controlling mosquito populations in the local area. You can follow our guide to doing so here, although this may be tricky given the amount of rain currently falling across Australia.

Wearing long sleeves, not going outside during the early hours of around dusk, and ensuring you’ve got a good dose of high-potency mosquito repellent will all help in warding off bites and possible contagion.

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