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Japanese Encephalitis
This is a mosquito acquired flavivirus infection that occurs in Asia.

At least 35,000 cases with 10,000 deaths are reported yearly.

The virus is similar to Yellow Fever and other flavivirus.
Most infections are not symptomatic.

1 in 250 infections cause illness after 5-15 days of incubation. Illness begins with a high fever, changes in mental status, gastrointestinal symptoms, and headache and followed by disturbances in speech, gout or other motor problems.

Symptoms progress to stupor and coma. 5-30% of cases are fatal and 1/3 of survivors may have neurological injury.

Treatment of Japanese Encephalitis is mostly supportive for affected people.

Japanese Encephalitis Vaccine
Japanese Encephalitis Vaccine is used to protect local populations in Asia who are mostly at risk.

Others such as military personnel or expatriates (people who live as residents during a transmission season) may consider the vaccine.

In most Asian countries the peak Japanese Encephalitis season lasts about 5 months and traveller's need only be vaccinated if at high risk during that time.

Risk factors for traveller's included:
1. Travel to endemic country
2. Travel during transmission season
3. Travel to rural areas (worse in rice paddies or near pig farms)
4. Extended period of residence or travel >4wks.
5. Advanced age 6. Pregnancy (risk to developing fetus)

Protective factors:
1. Repellents
2. Protective clothing
3. Residence in air-conditioned or well-screened areas
4. Permethrin mosquito nets

The Japanese Encephalitis vaccine is given in 3 dose administered at 0,7, and 14-21 days, with a booster at 3 years. Side effects of vaccination include local redness and soreness at vaccination site, low grade fever, and muscle aches. Allergic reactions to JEV have occurred up to 20-336 hours after vaccination, which are treatable with Corticosteroids and antihistamines.

In conclusion, Japanese Encephalitis is extremely rare in travellers but may be indicated in select people.

Japanese Encephalititis Links:

CDC http://www.cdc.gov/ncidod/dvbid/jencephalitis/

CDC http://www.cdc.gov/ncidod/dvbid/jencephalitis/

VADS corner on Japaneese Encephalititis http://www.vadscorner.com/je.html

WHOhttp://www.who.int/health_topics/en/