Japanese Encephalitis Remains a Risk in East Australia

New South West (NSW) Health recently reminded international travelers and Australian residents to protect themselves from mosquito bites during the summer of 2025 following Japanese encephalitis virus (JEV) detections.

In this year's first results, JEV was detected in mosquitoes in NSW's Moree area as of January 7, 2025. This area is located northwest of Sydney and west of Brisbane.

JEV was previously detected in mosquitoes in the Griffith area and feral pigs in the Narromine Shire local government area in December 2024.

NSW Health's Executive Director of Health Protection, Dr. Jeremy McAnulty, said in a media release, "Mosquitoes thrive in warm conditions, increasing the risk of mosquito-borne illnesses such as Murray Valley encephalitis, Japanese encephalitis, Ross River, and Barmah Forest viruses in parts of NSW."

“Each year from November to April, NSW Health undertakes surveillance across the state to provide important information about when mosquito-borne disease risk is elevated," Dr McAnulty added.

“These detections indicate the risk for mosquito-borne virus transmission is widespread, particularly in the 55 NSW local government areas at higher risk of JE in the inland regions."

“I encourage anyone planning to spend time outdoors in these higher-risk areas to take steps to protect against mosquito bites."

According to the World Health Organization, JEV is the leading cause of viral encephalitis in many Asian and Western Pacific Ocean countries. Twenty-four countries in the WHO South-East Asia and Western Pacific Regions have endemic JEV transmission, exposing more than 3 billion people to risks of infection.

The JE vaccine (JESPECT®) will be available in 2025 through local General Practitioners, Aboriginal health services, and pharmacists for people who live or regularly work in these areas. Information on eligibility for a free JE vaccine is available on the NSW Health website.

In the United States, Valneva SE's IXIARO® Japanese encephalitis virus vaccine is commercially offered at travel clinics and pharmacies.