The dengue fever outbreak in Japan that has sickened dozens prompted The US Embassy in Tokyo to put out the following advisory today:

Japan Image/CIA

The U.S. Embassy in Tokyo alerts U.S. citizens to the recent outbreak of dengue fever in Japan, the first since 1945.  Japanese media recently reported that 36 people who had not traveled out of Japan have contracted dengue fever.  Some people are believed to have been infected while walking in Tokyo’s Yoyogi Park.  Insecticide spraying was immediately initiated to eliminate mosquitoes.  Currently, Yoyogi Park remains open but cautions park visitors to wear long-sleeved shirts and pants and to use insect repellent.

Dengue fever is a viral illness transmitted by the Aedes aegypti and A. albopictus mosquitoes.  These mosquitoes bite during the day, most commonly at dusk and dawn.  According to the Center for Disease Control (CDC), symptoms of dengue may include vomiting, high fever, severe headaches, pain behind the eyes, extreme muscle and joint pain, rash, and mild bleeding (mild to severe or easy bruising).  There is no specific treatment or vaccine for dengue fever.  Persons exhibiting symptoms should seek the attention of a medical doctor immediately.  Upon your return to the United States, if you develop fever within two weeks of travel to Japan, you should specify to your health care provider that you have been to a dengue zone.

Prevention of dengue infection is focused on reducing mosquito exposure by using repellents, covering exposed skin by wearing long sleeves and long pants, treating clothing and tents with permethrin, and sleeping in screened or air conditioned rooms.  The CDC recommends that U.S. citizens carry and use CDC-recommended insect repellents containing DEET, picaridin, IR3535, and some oil of lemon eucalyptus and para-menthane-diol products provide longer-lasting protection.  To optimize safety and effectiveness, repellents should be used according to the label instructions.  DEET in combination with sunscreens may be less effective and is generally not recommended.

To obtain Centers for Disease Control and Prevention (CDC) travel notices, call the CDC at 1-800-CDC-INFO (1-800-232-4636) from within the United States, or 1-404-639-3534 from overseas, or visit the CDC website at:

For general information and updates in the event of an emergency, please monitor the Embassy Messages and Travel Alerts at

Current information on safety and security can also be obtained by calling 1-888-407-4747 toll free in the United States and Canada, or a regular toll line at 1-202-501-4444 for callers from other countries.  These numbers are available from 8:00 a.m. to 8:00 p.m. Eastern Time, Monday through Friday (except U.S. federal holidays).  You can also stay up to date by bookmarking our Bureau Consular Affairs website, which contains the current Travel Warnings, Travel Alerts, as well as the Worldwide Caution by “following” the Bureau of Consular Affairs on Twitter and “liking” the Bureau of Consular Affairs page on Facebook.

We urge all U.S. citizens in Japan to enroll online at the Smart Traveler Enrollment Program (STEP).  Registering gives U.S. citizens access to updated information on travel and security within Japan and makes it easier for the Embassy or Consulates to contact citizens in case of emergency.  If you are receiving this message in error or have completed your travel in Japan, please visit the Smart Traveler Enrollment Program (STEP) at to update your status.

Please consult the Country Specific Information Sheet for Japan, available on the Bureau of Consular Affairs website at