March 1, 2022
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Japanese encephalitis virus (JEV) has been detected in pig barns in New South Wales, Queensland and Victoria.
Australia’s chief veterinarian, Dr Mark Schipp, said JEV was confirmed by laboratory diagnosis in one pig barn in northern Victoria, six pig barns in New South Wales and one pig barn in Queensland.
“JEV is a mosquito-borne viral disease that occurs primarily in pigs and horses, but can cause disease in humans and rarely in other animals,” Dr Schipp said.
“Animals and people are infected by the bite of infected mosquitoes. It cannot be caught by eating pork or pork products. The disease is not transmitted from person to person.
“This is the first time the virus has been detected in South Australia, and biosafety authorities are working with their human health services to understand the implications and risks of human exposure.
“The Department of Health and the Department of Agriculture, Water and Environment are working closely together, with their state and territory counterparts.
“We meet regularly and work together to take the next steps in this situation.
“We ask anyone who works with pigs or horses, even if it is a pet in the yard, to monitor and report any possible signs of this disease.
“The most common symptoms in pigs are mummified or stillborn piglets, or piglets that show neurological problems within the first six months of life. The disease tends to be asymptomatic in adult sows, but boars can suffer from infertility and testicular congestion.
“Horses can experience a range of symptoms. Although most infected horses show no signs of illness, some more serious signs of JEV in horses include fever, jaundice, lethargy, anorexia, and neurological signs that can vary in severity.
“JEV is a nationally reportable disease, which means that if you suspect an animal is showing signs of the disease, you should report it (see contact details below). Steps should also be taken to protect animals from mosquitoes, such as applying safe insect repellent and putting a summer blanket on horses.
Acting Chief Medical Officer Dr Sonya Bennett said JEV infections can be contracted by humans through the bite of a mosquito. There are no confirmed human cases in Australia at this stage, although this is under active investigation. “We are aware that several cases of encephalitis of unknown cause have been identified in New South Wales, Victoria and South Australia over the past month.
“JE is also a reportable disease in humans and health authorities across the country are on alert for human cases and are in direct contact with people associated with affected barns,” Dr. Bennett said.
“Pigs are a major concern from a human health perspective because they can infect mosquitoes which then infect humans. This is not the case with horses.
“Serious illnesses resulting from JEV infection in humans are rare and most people will not have any symptoms if infected.
“However, a very small proportion of infected people may develop serious illness such as encephalitis and experience symptoms such as stiff neck, severe headache and coma, and more rarely, permanent neurological complications or death.
“Encephalitis is the most serious clinical consequence of JEV infection. The disease usually begins with symptoms such as sudden onset of fever, headache, and vomiting.
“Anyone with these symptoms, particularly if they have visited areas of Eastern Australia or South Australia where there has been high mosquito activity, should seek emergency medical attention.
“Clinicians should be aware of the possibility of infection caused by JEV in patients in encephalitis-affected areas and refer people for appropriate testing, after other common causes have been ruled out.
“Work is underway to plan targeted vaccinations. Two different vaccines are available for protection against JEV in Australia and are very safe and effective for adults and children.
“However, prevention is better than cure and there are simple steps we can all take to avoid our exposure to infected mosquitoes.
“People living in areas with high mosquito activity in eastern Australia should use an insect repellent containing picaridin or DEET on all exposed skin.
“Wear long, loose clothing when outdoors and ensure that accommodations, including tents, are properly equipped with mosquito nets or screens.
“We will continue to meet with state and territory health authorities to advance the public health response to this disease.”
To report suspected JEV in pigs or other animals, contact your local veterinarian or call Animal Disease Surveillance Hotline to 1800 675 888.
For more information on JEV in animals, visit Japanese encephalitis