Japanese encephalitis virus (JEV) is a mosquito borne disease. It is possible for infected mosquitoes to spread the virus to people and some animals including pigs, horses and water birds.

While the emergency response has now ended, JEV remains a nationally notifiable disease that poses significant risk to pig health and can have possible human health implications.

Protecting your people

To protect yourself and your staff, mosquito control measures need to be implemented in piggeries:

  • Cover-up with a loose-fitting long-sleeved shirt and long pants when outside or in naturally ventilated sheds
  • Use mosquito repellent containing DEET or picaridin on all exposed skin
  • Ensure mosquito control measures occur regularly on your property, including treating or removing potential mosquito breeding sites

For further information on the JEV vaccination program, including eligibility; please contact your state or territory’s Department of Health.

Protecting your pigs

The best way to prevent JEV infection in your herd is to reduce the number of mosquitos. Mosquitos breed very quickly in the right conditions. As far as possible, undertake the below actions.

Mosquito management that relies only on controlling adults is not effective or sustainable. An effective mosquito management program is only achieved by targeting all stages of the mosquito life cycle using a combination of methods. This is called integrated mosquito management, and it is the best way to reduce mosquitoes to protect workers and pigs. It requires a combination of:

  • Environmental management to reduce breeding and resting sites
  • Larviciding (removing larvae)
  • Adultciding (removing adult mosquitoes)
  • Ongoing monitoring and surveillance
  • Record keeping

More information on mosquito control is available on the Farm Biosecurity website.

If your herd becomes infected, the impact on pig production is manageable and is likely to be short-term if appropriate vector control takes place.

Protecting our industry

Key messages are:

  • JEV is a mosquito borne virus that impacts humans and animals
  • Commercially produced pork meat and pork products are safe to eat
  • Industry and government are working together to minimise the impact
JEV signs and symptoms

Signs of JEV infection in pigs can include:


  • Increase in stillborn, mummified or weak piglets
  • Deformed heads
  • Deformed legs
  • Swelling under the skin
  • Brain may be under-developed or absent
  • Shaky, wobbly or shivering
  • Increase in pre-weaning deaths


  • Increased return rates after mating
  • Delayed farrowing—more than 118 days
  • Increase in abortions


  • Inflamed or swollen testicles
  • Semen abnormalities
  • Infertility

Note: not all of these signs will be seen at every affected farm.

Most infected pigs will not show any of these signs and will behave normally while carrying the virus. If you do have some animals behaving abnormally or have noticed large numbers of mosquitoes in your herd, be alert.

JEV is a nationally notifiable disease, if you suspect JEV is present in your piggery you must notify government within 24 hours.

To notify government, please contact either:

  • Your herd or local government veterinarian
  • Call the Emergency Animal Disease Watch Hotline on 1800 675 888
Government advice

Federal and jurisdictional health agencies are monitoring the situation closely. For information relevant to your own jurisdiction, visit your state government agency via the links below:

For information regarding the disease incursion, visit the Department of Agriculture or download this fact sheet.

Info sessions

These info sessions are available for APL members to view. The information presented is relevant to all producers not just those in New South Wales, Queensland and Victoria.