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Japanese Encephalitis

What is Japanese encephalitis?

Japanese encephalitis (JE) is a disease spread through mosquito bites. Symptoms usually take 5-15 days to develop and include fever, headache, vomiting, confusion, and difficulty moving. Symptoms that develop later include swelling around the brain and coma. JE is a serious disease that may cause death.

Who is at risk?

Travelers who go to Asia are at risk for getting Japanese encephalitis (See map). For most travelers the risk is extremely low but depends on where you are going, the time of year, your planned activities, and the length of the trip. You are at higher risk if you are traveling to rural areas, will be outside frequently, or will be traveling for a long period of time.  In mild climates in northern Asia the risk for JE is greater in the summer and fall. In tropical and subtropical areas, there is a risk year-round.

What can travelers do to prevent Japanese encephalitis?

Culex tarsalis mosquito

Travelers can protect themselves from JE by getting JE vaccine and preventing mosquito bites.

Get JE vaccine, if recommended:

  • Talk to your doctor about your travel plans:
    • Your doctor can help you decide if you need the JE vaccine based on the length of your trip, the areas where you will be traveling, and your planned activities.
  • See your doctor at least 6 weeks before your trip:
    • The JE vaccine is given in 2 or 3 doses that are spaced over a month.
    • You should get the last dose at least 10 days before your trip.

Prevent mosquito bites:

woman getting injection
  • Cover exposed skin by wearing long-sleeved shirts, long pants, and hats.
  • Use an appropriate insect repellent as directed.
  • Higher percentages of active ingredient provide longer protection. Use products with the following active ingredients:
    • DEET (Products containing DEET include Off!, Cutter, Sawyer, and Ultrathon)
    • Picaridin (also known as KBR 3023, Bayrepel, and icaridin products containing picaridin include Cutter Advanced, Skin So Soft Bug Guard Plus, and Autan [outside the US])
    • Oil of lemon eucalyptus (OLE) or PMD (Products containing OLE include Repel and Off! Botanicals)
    • IR3535  (Products containing IR3535 include Skin So Soft Bug Guard Plus Expedition and SkinSmart)
    man spraying insect repellent on his arm
  • Always follow product directions and reapply as directed:
    • If you are also using sunscreen, apply sunscreen first and insect repellent second.
    • Follow package directions when applying repellent on children. Avoid applying repellent to their hands, eyes, and mouth.
  • Use permethrin-treated clothing and gear (such as boots, pants, socks, and tents). You can buy pre-treated clothing and gear or treat them yourself:
    • Treated clothing remains protective after multiple washings. See the product information to find out how long the protection will last.
    • If treating items yourself, follow the product instructions carefully.
    • Do not use permethrin directly on skin.
  • Stay and sleep in screened or air conditioned rooms.
  • Use a bed net if the area where you are sleeping is exposed to the outdoors.

If you are bitten by mosquitoes:

  • Avoid scratching mosquito bites.
  • Apply hydrocortisone cream or calamine lotion to reduce itching.

If you feel sick and think you may have JE:

  • Talk to your doctor or nurse if you feel seriously ill, especially if you have a fever.
  • Use acetaminophen. Do not take pain relievers that contain aspirin and ibuprofen (Advil), it may lead to a greater tendency to bleed.
  • Get lots of rest, and drink plenty of liquids.
  • Avoid spreading the disease by preventing more mosquito bites.

Traveler Information

Clinician Information

 
Contact Us:
  • Centers for Disease Control and Prevention
    1600 Clifton Rd
    Atlanta, GA 30333
  • 800-CDC-INFO
    (800-232-4636)
    TTY: (888) 232-6348
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