The health ministry said Wednesday it has confirmed that someone has contracted dengue fever while in Japan for the first time in nearly 70 years.
A Japanese teen in Saitama Prefecture with no record of overseas travel ran a high fever late this month and was hospitalized in the city of Saitama. Her condition is stable, the ministry said.
Around 200 Japanese are infected with the viral disease while traveling overseas annually, but no domestic infection had been confirmed since 1945, according to the Health, Labor and Welfare Ministry.
It’s likely a mosquito caused the infection, probably by previously biting someone who caught the virus overseas, the ministry said.
Chief Cabinet Secretary Yoshihide Suga, in confirming the report, said Wednesday that the news was not cause for alarm because the illness is not transmitted directly from person to person.
Sufferers are struck with a sudden fever around three to seven days after transmission, accompanied by head and muscle pains and a rash. Most sufferers have mild symptoms, but some may develop bleeding gums or nosebleeds.
Most patients are only given drugs to reduce their fever, as there are no effective drugs or vaccines for the disease itself.
The National Institute of Infectious Diseases is checking whether there are other infected people living close to the teen and has called on prefectural governments to be on the alert. The disease does not spread from person to person.
Dengue fever, which often spreads in tropical and subtropical areas in Asia, Latin America and Africa, is transmitted by tiger and dengue mosquitoes.
In Japan, tiger mosquitoes are found as far north as southern Aomori Prefecture. Any outbreak would be limited in scope as not all the mosquitoes carry the virus and they die off in winter.
There have been 98 confirmed cases of dengue infection from overseas this year through Aug. 17, according to the ministry. Japan reported 249 cases last year.
Last August, a German woman who visited Kyoto and Nagano prefectures was diagnosed with the disease after returning home.
Dengue has been spreading in recent years worldwide, with 50 million to 100 million infections a year in more than 100 countries. According to the World Health Organization, before 1970 only nine countries had experienced dengue epidemics.