Latest emergency response news
Updated: 16 July 2026
There is no active emergency animal disease response for Japanese encephalitis virus (JEV) in Australia.
The national JEV outbreak emergency response — declared a communicable disease incident of national significance in March 2022 — concluded on 16 June 2023.
In May 2026, JEV was detected in pigs in Queensland. This is the first confirmed detection in Queensland pigs since May 2025.
The detection is not unexpected, as JEV continues to circulate in Australia, particularly during periods of mosquito activity.
About Japanese encephalitis
JEV is a mosquito-borne viral disease. The virus belongs to the Flavivirus family, which also includes Murray Valley encephalitis and West Nile virus.
JEV is a zoonotic disease. It can infect both animals and humans. It is only spread by infected mosquitos and cannot be transmitted through direct contact between animals and people.
The virus is maintained in nature through a transmission cycle involving mosquitoes and animals. Wading waterbirds are the main natural hosts and play a key role in maintaining and spreading the virus.
Pigs are amplifying hosts. Infected pigs can develop high levels of virus in their blood, which can infect feeding mosquitoes and continue the transmission cycle. Feral pigs may also contribute to the spread.
Horses and humans are considered “dead-end” hosts. They can become infected but do not develop enough virus in their blood to infect mosquitos. As such, they do not contribute to ongoing transmission.
JEV has been detected in many animal species worldwide, including birds, pigs, horses and other mammals, as well as reptiles and amphibians. Most infections in animals do not cause obvious signs of disease.
JEV is not a food safety concern. Commercially produced pork and pork products are safe to eat.
Signs of JEV in pigs
In pigs, JEV most commonly affects reproduction. Signs may include:
- increased rates of mummified or stillborn piglets
- weak piglets, sometimes with neurological signs at birth
- neurological signs in young pigs, such as tremors or paddling
- infertility in boars, sometimes with swollen or congested testes.
Signs of JEV in horses
Many JEV infections in horses do not cause obvious illness. When signs do occur, they are usually mild, but severe and potentially fatal encephalitis can develop. Signs may include:
- elevated temperature and lethargy
- jaundice and loss of appetite
- neurological signs of varying severity, including incoordination, difficulty swallowing, impaired vision and, rarely, agitation or over-excitement.
Important: JEV in horses can look similar to Hendra virus, which can be fatal in humans. Always use appropriate personal protective equipment (PPE) and contact your veterinarian before handling a sick horse.
Human health risks
JEV is a serious human health disease, although most infections cause no symptoms.
In rare cases, infection can lead to encephalitis, which can be fatal or cause long‑term neurological complications.
People cannot catch JEV from animals or from eating pork or other animal products. Infection occurs only through the bite of an infected mosquito.
A human vaccine is available in Australia for eligible priority groups. For advice on vaccination, contact your state or territory health department or your general practitioner.
Japanese encephalitis in Australia
Before 2022, locally acquired JEV infections in mainland Australia were extremely rare.
In February 2022, JEV was detected in commercial piggeries in New South Wales, Queensland and Victoria, resulting in the largest outbreak ever recorded in Australia. The outbreak affected more than 80 piggeries and led to 45 human cases, including seven deaths.
This outbreak was linked to JEV genotype IV, likely spread by infected waterbirds during periods of extensive flooding and high mosquito activity across eastern Australia.
JEV is now established in parts of eastern and south-eastern Australia. As the virus is maintained in wild waterbird and mosquito populations, eradication is not feasible. Detections are expected to occur seasonally during periods of peak mosquito activity.
As JEV is not spread directly between animals or from animals to people, detections in animals do not trigger livestock movement restrictions or quarantine. Response activities instead focus on public health measures, mosquito surveillance and mosquito control.
How to report Japanese encephalitis
JEV is a nationally notifiable animal disease. If you suspect JEV in pigs or horses, report it immediately by contacting:
- your private veterinarian
- your state or territory agriculture department
- the Emergency Animal Disease Hotline on 1800 675 888.
Japanese encephalitis overseas
JEV is endemic across much of south and southeast Asia, the Western Pacific and parts of northern Australia. It is the most common cause of viral encephalitis in Asia, causing an estimated 100,000 human cases and 25,000 deaths per year.
The disease is usually seasonal in temperate regions, linked to increased mosquito activity. It circulates more continuously in tropical areas.
JEV genotype I is the dominant strain circulating globally. The 2022 Australian outbreak was caused by genotype IV, a strain previously rare and largely confined to parts of Southeast Asia and the Western Pacific.
The geographic range of JEV has expanded in recent decades, driven by climate change, changes in land use, mosquito ecology and waterbird movements.
Resources for producers
AUSVETPLAN resources
AUSVETPLAN is a series of manuals and procedures containing the nationally agreed approach for responding to emergency animal disease incidents. The following documents are relevant to a JEV response.