Japanese Encephalitis Virus Disease

Japanese encephalitis virus (JEV) is a mosquito-borne virus that is found across Asia, including Southeast and East Asia, parts of the Pacific, and India. JEV is a serious disease that can cause inflammation in the brain, often leading to seizures, meningitis, permanent disability, and even death. The disease primarily affects children and the elderly.

JEV is spread through the bite of an infected mosquito. The virus lives in nature in a cycle between mosquitoes and birds, with pigs serving as occasional intermediate hosts. Humans become infected by coming into contact with mosquitoes that have fed on an infected bird or pig. JEV can also be spread from pregnant mother to her unborn baby.

Symptoms of JEV usually appear a week or two after a person has been bitten by an infected mosquito. The most common symptoms include fever, headache, tiredness, and vomiting. In some cases, these symptoms may be accompanied by neck stiffness, confusion, seizures, and paralysis, which may be permanent.

Although there is no specific cure available for JEV, early diagnosis and treatment can help reduce the severity of symptoms and prevent more serious complications. Treatment should include rest, drinking plenty of fluids, and taking medications to reduce fever and headaches. In more severe cases, hospitalization and intensive care may be necessary.

Prevention

The best way to prevent JEV is to avoid being bitten by infected mosquitoes. Personal protection methods include:

Wearing long-sleeved tops and pants when outdoors at dawn and dusk when mosquitoes are most active.
Using mosquito repellent (e.g. DEET, Picaridin, or Oil of Lemon Eucalyptus) on exposed skin.
Sleeping in screened-in or air-conditioned rooms.
Using insecticide-treated bed nets when sleeping outdoors or in unscreened dwellings.
Reducing mosquito breeding areas, such as standing water around the home.

In addition, a vaccine is available for people traveling to areas where JEV is common. The vaccine is approved for use in children over 1 year old and adults, and should be administered at least one month before traveling.