JAPANESE ENCEPHALITIS: Small Creature. Big Threat.

Dangerous. Dreary. Deadly. Never would you have thought that this little creature could cause this much catastrophe. Mosquitoes cause serious health problems by transmitting many dreadful diseases such as malaria, dengue and the Zika disease. Another potentially severe disease is Japanese Encephalitis (JE). The World Health Organization (WHO) estimates there are around 68,000 cases of Japanese encephalitis worldwide each year.1


Japanese encephalitis is a viral infection that is transmitted from animals to humans through the bite of an infected mosquito. Pigs and wading birds are the main hosts of JE, hence the transmission of the virus occurs primarily in rural agricultural areas. In some areas of Asia, these conditions can occur near urban centres.2

In most temperate areas of Asia such as China, Korea and Japan, the JEV flourishes in warm climates or during the warm season, which is when large epidemics often occur.3,4 In the tropics and subtropics such as Malaysia, Indonesia and the Philippines, cases of virus transmission occur year round, but often intensify during rainy seasons.3,4


Most people infected by the Japanese encephalitis virus either appear to have no symptoms or mild ones, some of which might be mistaken for flu1. The mild symptoms consist of fever and headache. However, around 1 in every 250 people who become infected with Japanese encephalitis develop more severe symptoms due to encephalitis (brain infection).1 The severe symptoms may include stiff neck, seizures and even coma1. About 1 in 4 person with encephalitis dies due to permanent brain damage, while about half of the survivors end up being permanently disabled.5 It is believed that infection in a pregnant woman could harm her unborn baby.5

Immediately seek medical advice if you or your child encounter any of the symptoms and have recently visited, or are still in an area where JE is still active. Supportive care in hospitals can help reduce the risk of death or disability by treating symptoms and preventing complications.


Unfortunately, there is no specific anti-viral drug that is available to treat Japanese encephalitis.6 As Asia is often our frequent travel destination, prevention is key for such a devastating disease. Wear mosquito repellent or long sleeved clothing. Vaccination can further reduce the risk of infection. Talk to your paediatrician or healthcare provider for more details and get peace of mind by protecting your family and yourself against JE.



  1. NHS Choices. Japanese Encephalitis. Available at http://www.nhs.uk/Conditions/Japanese-encephalitis/Pages/Introduction.aspx. Last accessed May 2016.
  2. Transmission of Japanese Encephalitis Virus. CDC. Available at http://www.cdc.gov/japaneseencephalitis/transmission/index.html Last accessed May 2016.
  3. Risk of Japanese Encephalitis by country, region and season – CDC 2010. Available at http://www.itg.be/itg/Uploads/MedServ/NJAPENC%20bijlage.pdf. Last accessed May 2016.
  4. Centers for Disease Control and Prevention. Infectious Diseases Related to Travel. Available at http://wwwnc.cdc.gov/travel/yellowbook/2016/infectious-diseases-related-to-travel/japanese-encephalitis. Last accessed May 2016.
  5. Centers for Disease Control and Prevention. Japanese Encephalitis VIS. Available at http://www.cdc.gov/vaccines/hcp/vis/vis-statements/je-ixiaro.html. Last accessed May 2016.
  6. Japanese encephalitis: epidemiology, prevention and current status of antiviral drug development. Available at http://www.tandfonline.com/doi/abs/10.1517/21678707.2014.934222. Last accessed May 2016.


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