Japanese Encephalitis Virus Detected in Lake Wyangan Mosquitoes

Located on Australia's southeast coast, New South Wales (NSW) Health recently reminded everyone to take action to avoid virus-carrying mosquitoes this summer.

NSW Health's Executive Director of Health Protection, Dr. Jeremy McAnulty, said in a media release on December 7, 2024, that mosquitoes thrive in warm conditions, increasing the risk of mosquito-borne illnesses such as Japanese encephalitis in parts of NSW.

Almost two-thirds of NSW's population, 5.3 million, lives in the greater Sydney area along Australia's southeast coast. Over 3.7 million international travelers visited NSW in the year ending June 2024.

"Each year, NSW Health undertakes mosquito surveillance across NSW from November to April, which provides important information about when mosquito-borne disease risk is elevated," Dr. McAnulty stated.

"As part of this routine surveillance, the Japanese encephalitis virus (JEV) was recently detected in a mosquito sample in Lake Wyangan, located northwest of Griffith, on December 3, 2024."

Griffith City Council urges residents to follow the "Spray up, Cover up, Clean up, Screen up!" guidelines.

NSW Health did confirm that there have been no human cases of JEV since October 2022.

However, mosquitos in NSW can potentially carry a range of other viruses for which there are no vaccines, including Murray Valley encephalitis, Ross River, and Barmah Forest viruses.

"This is a timely reminder, both to Griffith residents and to anyone planning to enjoy the outdoors, to take protective measures this summer against mosquitoes," he said.

Australia is not alone, as over 20 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. 

In NSW, a free JEV vaccination is available through local General Practitioners, Aboriginal health services, and pharmacists for people aged two months or older. 

"Japanese Encephalitis is a serious disease with a 20-30% mortality rate," commented Crockett Tidwell RPh, CDCES, CTH, International Society of Travel Medicine Certificate in Travel Health™.

"Travelers should take time to understand their risk and mitigate that risk by preventing mosquito bites and getting vaccinated when indicated," added Tidwell, Clinical Services Manager at United Supermarkets, Lubbock, Texas.

In the United States, Valneva SE's IXIARO® (JESPECT®) inactivated, adsorbed, Vero cell culture-derived Japanese encephalitis virus vaccine are commercially available at travel clinics and pharmacies in 2024.

Note - This article was updated on Dec. 18, 2024, for headline and related local content.