by Amy Scholten, MPH
Japanese encephalitis is an infection from a mosquito. Rarely, it can affect the brain and nervous system. When this happens, it can be serious and even life-threatening.
Japanese encephalitis is caused by a virus. It is spread to humans from the bite of an infected mosquito. The virus is not spread from person to person.
The risk of Japanese encephalitis is highest in areas that have outbreaks. Outbreaks have happened in rural parts of China, Korea, Japan, Taiwan, and Thailand. These countries now control the disease with vaccinations.
Countries that still have outbreaks are:
Lab workers exposed to the virus also have some risk.
Most people infected with Japanese encephalitis do not have symptoms. If symptoms happen, they can range from mild to severe.
Symptoms may be:
The doctor will ask about your symptoms and health history. A physical exam will be done.
Tests may be done to diagnose the infection. They may be:
Imaging tests may be done to check the brain. They may include:
There is no specific treatment for Japanese encephalitis. Treatment depends on how severe the disease is. The goal is to manage symptoms and problems. Hospital care may be needed.
Depending on the symptoms, options may be:
The risk of Japanese encephalitis may be reduced by:
The risk may also be reduced by:
Centers for Disease Control and Prevention
Infectious Diseases Society of America
Japanese encephalitis. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/japaneseencephalitis. Accessed April 5, 2021.
Japanese encephalitis VIS. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/vaccines/hcp/vis/vis-statements/je-ixiaro.html. Accessed April 5, 2021.
Japanese encephalitis virus vaccine, inactivated. EBSCO DynaMed website. Available at: https://www.dynamed.com/drug-monograph/japanese-encephalitis-virus-vaccine-inactivated. Accessed April 5, 2021.
Keng LT, Chang LY. Japanese encephalitis. CMAJ. 2018;190(21):E657
Mosquito avoidance. EBSCO DynaMed website. Available at:https://www.dynamed.com/prevention/mosquito-avoidance. Accessed April 5, 2021.
Last reviewed December 2020 by EBSCO Medical Review Board David L. Horn, MD, FACP
Last Updated: 4/5/2021
EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
To send comments or feedback to our Editorial Team regarding the content please email us at firstname.lastname@example.org. Our Health Library Support team will respond to your email request within 2 business days.
All rights reserved.