Japanese encephalitis update

Information from the Department of Agriculture, Water and Environment about Japanese encephalitis in Australia.

UPDATE: How to keep up to date with new information.

As  Japanese Encephalitis Virus continues to spread we are receiving information on a regular basis from the Department of Agriculture, Water and Environment and other sources. 

Information is updated on the AVA website as it becomes available on the Japanese encephalitis page under Emergency Animal diseases on the home page. 

Current situation as of 07 March 2020:

• Japanese encephalitis (JE) has been confirmed in pigs in Victoria, New South Wales, South Australia and Queensland.
• 21 infected pig farms have been reported. The infected piggeries are in QLD (1), NSW (13), Victoria (6) and SA (1).
• Three human cases of JE have been confirmed, with one in Queensland and two in NSW. It is anticipated that more cases will be confirmed shortly.
• o   The confirmed case in Queensland had recently travelled to regional southern Queensland and is currently being treated in a Brisbane hospital.
• o   The two cases in NSW are both residents of the NSW-Victoria border region and are currently being treated in hospital.
• There are 20 cases of acute encephalitis of unknown cause identified across multiple jurisdictions which are under investigation.
• o   This is an ongoing public health outbreak investigation. Case numbers may increase or decrease as further information comes to light or case definitions are revised.
• o   Victoria has announced that there have been eight suspected human cases including six people who have been hospitalised in the state. Two of these cases are in children under 10 years old.
• o   NSW have announced a highly probable case in a resident in the NSW-Victoria border region. There are also several more NSW patients where investigation is ongoing.

Update from 4 March 2022

Key Messages: 

• Japanese encephalitis has been confirmed in 13 piggeries and movement restrictions apply to infected pig properties 
• There are no state or territory movement restrictions on the movement of horses. 
• One human case of Japanese encephalitis has been confirmed in Queensland. The confirmed case had recently travelled to regional southern Queensland. 
• The Consultative Committee on Emergency Animal Diseases met on 3 March and endorsed a paper that will be considered by the National Management Group. The paper recommends that a national response plan be developed, based on containing the disease, and that further surveillance be done in mosquitoes, pigs and horses in affected areas. 

Current Situation 

• Japanese encephalitis has been confirmed by laboratory diagnosis in 13 piggeries. Three are in Victoria, one in southern Queensland, and 8 across New South Wales.  
• Movement restrictions have been applied to infected pig properties.
• A cross-jurisdictional vector control working group with representatives from human health, animal health and industry has been formed to provide recommendations on mosquito control for piggeries. 
• Japanese encephalitis is not a food safety concern. Commercially produced pork meat or pork products are safe to consume. 
• Japanese encephalitis is an acute mosquito-borne viral disease that can cause reproductive losses and encephalitis in susceptible species. The disease occurs mostly in pigs and horses but can also rarely cause disease in people. 
• Animals and people become infected through the bite of infected mosquitoes. The normal lifecycle of Japanese encephalitis is between waterbirds and mosquitoes, which on occasion, may spill over to pigs and horses.  
• The Australian Government Department of Health and Australian Government Department of Agriculture, Water and the Environment are collaborating closely, together with state and territory counterparts.  
• The Consultative Committee on Emergency Animal Diseases met on 3 March and endorsed a paper that will be considered by the National Management Group. The paper recommends that a national response plan be developed, based on containing the disease, and that further surveillance be done in mosquitoes, pigs and horses in affected areas. 
• The committee is also looking at how to manage the risk of moving pigs and semen from infected areas to locations where the disease hasn’t been detected. 
• There are no state or territory movement restrictions on the movement of horses. 
• It is not known how the virus came into mainland Australia. The movement of infected mosquitoes or migratory waterbirds may have played a part in the virus’ spread. 
• Australia has national plans in place to respond to animal disease incursions. The Japanese Encephalitis AUSVETPLAN outlines the principles for responding to this disease. 
• Information about this disease incursion is available here. 

Reporting 

• Japanese encephalitis virus is a nationally notifiable disease which means if you suspect an animal is showing signs of the disease, you must report it.  You can do this by calling  the national Emergency Animal Disease Watch Hotline on 1800 675 888. This will put you in touch with your state or territory’s agriculture department.

How to identify the disease in animals 
 
Pigs 

• Japanese encephalitis virus is not spread directly from pigs to people, and spread from pig to pig is rare. The virus is primarily spread by mosquitoes. 
• In pigs, the most common clinical signs are mummified and stillborn or weak piglets, some with neurological signs. 
• Piglets infected after birth can develop encephalitis which presents as paddling or other neurological signs in the first six months of life.  In other cases, wasting, depression or hindlimb paralysis may be seen in suckling piglets and weaners.  
• Adult sows do not typically show overt signs of disease. If boars are present on farm, they may experience infertility and oedematous, and congested testicles.

Horses 

• In horses many cases are subclinical, meaning that they can be infected but show no signs of the disease. Most clinical disease is mild, however more severe encephalitis can occur which may be fatal.  
• Signs include an elevated temperature, jaundice, lethargy, anorexia and neurological signs which can vary in severity.  
• Neurological signs can include incoordination, difficulty swallowing, impaired vision, and rarely the horse becomes over excited. 
• While reports of the disease in other species are rare, overseas the disease has been reported in donkeys. 
• Horses are known to be a ‘dead end host’. They do not carry a blood infection that will reinfect mosquitoes.

Biosecurity 

Pigs 

• Pig producers are asked to be highly vigilant for signs of this disease and report unexplained pig abortions or stillbirths. 
• Many piggeries operate under the national Australian Pig Industry Quality Assurance program which sets high biosecurity and hygiene standards for commercial piggeries. 
• People working with pigs, including those who may have a small herd or pet, should take steps to control mosquitoes, as well as of course continue to use effective biosecurity measures.   
• You can find out more at farmbiosecurity.com.au and the National Pork Biosecurity Manual which provides in-depth detail on biosecurity practices and management in piggeries. 

Horses 

• Horse owners can also put measures in place to help their horses avoid mosquito bites. Put a light, hooded rug on them, a fly mask, and if the horse allows, apply a safe insect repellent. Do not spray the repellent around or above their eyes.  
• The Australian mosquito that transmits JE feeds at night and is reluctant to enter dwellings, so stabling horses between dusk and dawn is beneficial. 
• Additional measures to protect stabled horses are listed in the JE AUSVETPLAN Response Strategy, including topical treatment with insect repellents. 

Exports and trade

• The Department of Agriculture, Water and the Environment provides the certification for live animals, meat and meat products for export to overseas markets.  
• The department is working with horse exporters to ensure horses meet importing country requirements for Japanese encephalitis. There are 12 markets that Australia exports horses to that have import requirements in place for this disease. 
• The department will work with trading partners should any other issues arise around the export of pig meat, offal and pet food, due to this outbreak. 

Human health advice 

• One human case of Japanese encephalitis has been confirmed in Queensland. The confirmed case had recently travelled to regional southern Queensland and is currently being treated in a Brisbane hospital. 
• There are a number of suspected human health cases currently under investigation. 
• JEV infections can be contracted by humans through the bite of a mosquito. 
• JE is also a notifiable disease in humans and health authorities across the country are on the alert for human cases and are in direct contact with people associated with the affected piggeries. 
• Pigs are the focus from a human health perspective as they can infect mosquitoes who then infect humans. This is not the case with horses. 
• Severe illness arising from JEV infection in humans is rare and most people will have no symptoms at all if infected. 
• Less than 1% of infected people 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. 
• Clinicians should be aware of the possibility of infection caused by JEV in patients in affected areas with encephalitis and refer people for appropriate testing, after other common causes have been excluded. 
• There are simple steps we can all take to avoid our exposure to infected mosquitos. 
  • People in areas of high mosquito activity in Eastern Australia should use mosquito repellent containing picaridin or DEET on all exposed skin. 
  • Wear long, loose fitting clothing when outside, and ensure accommodation, including tents, are properly fitted with mosquito nettings or screens.
• There is work underway on targeted vaccinations. Two different vaccines are available for protection against JEV in Australia and are very safe and effective for both adults and children. 
• The Australian Government Department of Health and health authorities in the states and territories to progress the public health response to this disease. 

Response arrangements  

• The Consultative Committee on Emergency Animal Diseases provides technical and scientific advice in response to exotic animal disease outbreaks. The Committee is chaired by Australia’s Chief Veterinary Officer and comprises the Chief Veterinary Officers from each state and territory, other specialists from government, Animal Health Australia, and representatives the pig and horse industries. The Australian Government Department of Health is an Observer on this committee. 
• The National Management Group (NMG) consists of Chief Executive Officers from government agencies responsible for agriculture and affected industry organisations. It is chaired by the Secretary of the Australian Government Department of Agriculture, Water and the Environment. Animal Health Australia is a non-voting member. 
• NMG makes decisions on whether to support national eradication programs for disease outbreaks under the Emergency Animal Disease Response Agreement. NMG considers recommendations provided by the consultative committee before making decisions on whether a pest or disease is technically feasible to eradicate.  
• The Emergency Animal Disease Response Agreement is a formal legally binding agreement between Animal Health Australia, the Australian, state and territory governments, and national livestock industry bodies. The Agreement covers the management and funding of nationally agreed responses to emergency animal disease incidents.

Alerts as PDFs

Emergency animal disease alert for veterinarians_approved.pdf

Emergency animal disease alert_horses_approved.pdf

Emergency animal disease alert_pigs_approved.pdf