On October 16, 2019, the Tokyo Metropolitan Government announced that a medical institution in Tokyo submitted a report of a dengue fever patient who had no overseas travel history. Dengue fever is a viral infection caused by the bite of a dengue-infected mosquito (Aedes aegypti/Aedes albopictus), and is not transmitted directly from person to person. Mosquitoes (Aedes albopictus) are active from mid-May to late October, and die when the temperature drops. For prevention, it is important to avoid being bitten during mosquito activity. Avoid exposing your skin as much as possible, and when working outdoors, wear long sleeves, long pants, and socks, and use insect repellent. Also, be careful not to create places where mosquito larvae can grow, such as puddles. (Do not leave water in buckets, old tires, water tanks, planters, flowerpot saucers, etc.) If you are bitten by a mosquito and have symptoms such as fever, please consult your local medical institution. For more information, please see the related information below.

Related information

• Ministry of Health, Labor and Welfare: Dengue Fever (External link)
• Tokyo Metropolitan Infectious Disease Surveillance Center: Dengue fever (External link)
• Q&A about dengue fever (External link)
• Concrete measures against mosquitoes: Clinical practice guidelines for mosquito-borne infections (see page 33 for how to use repellents) (External link)

Leaflet on measures against mosquitoes (Ministry of Health, Labor and Welfare)
*Unauthorized use for purposes other than educational purposes is prohibited.

• Caution (PDF 312.7KB)
• Occurrence source (PDF 323.4KB)