Japanese encephalitis virus is a disease that's spread by mosquitoes and can infect waterbirds, pigs, horses and on rare occasions, humans. The virus has been detected in Australia in piggeries across several states, including Queensland, Victoria, New South Wales and South Australia.
Japanese encephalitis virus has now been detected in pigs and humans in Western and Southern NSW, as well as in Queensland, Victoria, the Northern Territory and South Australia. Is meat from infected animals safe to eat?
Two in New South Wales, two in South Australia, one in Victoria, one in Queensland and one in the Northern Territory.
About Japanese encephalitis
JEV is endemic to parts of Asia and the Torres Strait region of Australia. JEV has now also been detected in humans, animals and mosquitos in mainland Australia. Infection in humans is most commonly asymptomatic, but on rare occasions it can result in severe disease and even death.
Panel A shows residential location for 40 of 46 human JEV cases in the current (2021–2023) outbreak and five of five cases in historical JEV outbreaks (1995 and 1998) in Australia. The location of symbols corresponds to the Local Government Area of residence of cases and may not reflect place of exposure.
Japanese encephalitis virus occurs in many parts of southern and eastern Asia, and in recent years has extended beyond its traditional boundaries to eastern Indonesia, Papua New Guinea and the Torres Strait. Japanese encephalitis is now considered endemic in the Torres Strait region.
Japanese encephalitis (JE) virus infection has been identified in a Lake Cargelligo resident, the first NSW case of JE this mosquito season. The case is in an older man from Lake Cargelligo who is likely to have acquired the infection in early November. He is continuing to recover at home from an unrelated illness.
Most people infected with JE do not have symptoms or have only mild symptoms. However, a small percentage of infected people develop inflammation of the brain (encephalitis), with symptoms including sudden onset of headache, high fever, disorientation, coma, tremors and convulsions. About 1 in 4 cases are fatal.
Overall, it's estimated there's less than 1 case of Japanese encephalitis for every million travellers. But there are certain activities that can increase your risk of becoming infected, such as: living or travelling in high-risk areas for a long time. visiting rural areas, particularly during the rainy season.
Fewer than 1% of Japanese encephalitis cases are believed to be symptomatic, leading researchers to estimate the number of overall cases to be in the thousands. For those developing symptoms, the fatality rate is estimated at around 30%, with around half of survivors said to have long-term neurological damage.
Sadly, seven people have died. Dr Armstrong said that JEV was transmitted by mosquitoes, it was now more important than ever that people take measures to avoid mosquito bites wherever possible.
Epidemiology. Japanese encephalitis (JE) is the leading cause of viral encephalitis in Asia, with up to 70,000 cases reported annually. Case-fatality rates range from 0.3% to 60% and depend on the population and age.
Japanese encephalitis virus is present in Asia and Oceania, from Japan to India, Pakistan and Australia. Outbreaks are erratic and spatially and temporally limited phenomena, occurring quite unpredictably. The virus is a leading cause of viral encephalitis in Asia, with 30 000 to 50 000 cases reported annually.
South Burnett. southwest area of Toowoomba Regional Council (surrounding and including Millmerran) Torres Strait.
It takes 5 to 15 days after the bite of an infected mosquito to develop symptoms.
As of 28 April 2022, a cumulative of 37 human cases of Japanese encephalitis (25 laboratory-confirmed cases and 12 probable cases) have been reported in four states in Australia with symptom onset dating back to 31 December 2021.
A vaccine for Japanese encephalitis is recommended if you're travelling to a part of the world where the virus is found, especially if: you're staying for more than a month. you're staying in a rural area.
Risk is increased for long-stay travelers (with extensive unprotected outdoor, evening/nighttime exposures) going to rural areas in affected countries, especially during the JE virus (JEV) transmission season. Symptoms include sudden high fever, nausea, headache, and altered mental status.
Transmission is seasonal in temperate climates and peaks between May and October, but the risk persists year-round in more tropical climates. The time of greatest risk for infection is during the rainy season and the pre-harvest period in rice cultivating areas due to increased mosquito vector populations.
Anyone who has a severe (life threatening) allergy to any component of JE vaccine should not get the vaccine. Tell your doctor if you have any severe allergies. Pregnant women should usually not get JE vaccine. If you are pregnant, check with your doctor.
The best way to avoid Japanese encephalitis is to not get bitten by mosquitoes. Protect yourself: use insect repellent. The best mosquito repellents have diethyltoluamide (DEET), picaridin, or oil of lemon eucalyptus.
About Japanese encephalitis vaccination
Primary immunisation should be completed at least one week prior to potential exposure to Japanese encephalitis virus. Once you have received both doses, you are protected against Japanese encephalitis for 12-24 months. After one year, you require a booster.
There are two safe and effective JEV vaccines: Imojev : one dose vaccine available for use in people aged 9 months and older. JEspect / Ixiaro: two doses for use in infants and children aged ≥2 months and older, including people who are immunocompromised, and pregnant women.
As of August 1, 2022, a total of 40 cases of infection that had led to 5 deaths had been reported. In 1995 and 1998, in the tropical far north of Australia in Queensland, 5 cases of Japanese encephalitis (and 2 deaths) caused by genotype 2 were identified.
A total of 434 cases of JEV were recorded between July 1 and September 23, 2022, in 17 separate districts within Assam, India. The precise demographics of these JEV cases remain unknown. The case fatality rate in Assam during this outbreak was 21.43% (93); however, underreporting may occur.