Japan is urging local authorities to be on the lookout for further outbreaks of dengue fever, after confirming another 19 cases that were contracted at a popular local park in downtown Tokyo.
The cases announced Monday raise to 22 the number of dengue infections thought to have been contracted locally. The health ministry earlier reported three local cases, the first in nearly 70 years.
Tokyo began spraying Yoyogi park, a vast green area next to Meiji Shrine that is popular with young Japanese and performance artists, after discovering the outbreak.
Japan sees dozens of imported cases of dengue fever each year, mostly in tourists who catch the illness while traveling in tropical regions. The disease, which is transmitted only by mosquito, was common in Japan during World War II but was locally eradicated for decades.
Dengue causes symptoms including fever, severe joint pain and headaches. There is no treatment, and some of those infected can suffer from severe and life-threatening bleeding.