Japanese Encephalitis Virus Outbreak Declared in Australia

Australia's government recently declared the unfolding Japanese encephalitis virus (JEV) outbreak in Queensland a Communicable Disease Incident of National Significance.

On March 3, 2022, Queensland officials confirmed a human case of JEV was being treated in a Brisbane hospital.

Furthermore, the Department of Health is aware of other cases in multiple states of encephalitis of unknown origin. There have been eight suspected human cases of JEV infection in Victoria in the past week, including six people in the hospital.

Australia's Acting Chief Medical Officer, Dr. Sonya Bennett, confirmed on March 4, 2022, "A national working group of communicable disease, vaccine, and arbovirus experts has been established to support the response, including mosquito surveillance and control measures and identification of those at direct risk, and for the rollout of vaccines."

"Public health communications regarding mosquito protection will target affected communities."

According to the U.S. CDC, humans can become infected with JEV through the bite of an infected mosquito.

However, JEV cannot be transmitted between humans, and it cannot be caught by eating pork products.

Less than 1% of people infected may develop a serious illness and, more rarely, permanent neurological complications or death.

The WHO says JEV is the leading cause of viral encephalitis in many countries of Asia, with an estimated 68,000 clinical cases every year.

Although JEV was first recognized as a public health threat in Japan, molecular studies suggest that ancestral JEV emerged from the Indonesia/Malaysia region.

Asian countries are highly concerned about JE because of conditions, such as epidemic areas, distribution of vectors, climate, geographical location, social health, and economics. 

There are two JEV vaccines available globally.

Valneva SE's Ixiaro is an inactivated, adsorbed Vero cell culture-derived vaccine approved by the U.S. FDA. 

The Ixiaro vaccine was developed through a cooperative agreement with the Walter Reed Army Institute of Research. It is prepared by propagating JEV strain SA14-14-2 in Vero cells.

As of March 6, 2022, the CDC had not issued a Travel Advisory for Queenland's JEV outbreak.