TOKYO, Sept. 1 (Xinhua) -- Japanese health authority confirmed 19 new cases of dengue fever on Monday, bringing the total number of infected people to 22 in the first locally contracted cases in 70 years, local media reported Monday.
None of the sufferers had record of overseas travel recently, but they all have been to Tokyo's Yoyogi Park and are thought to have been bitten there by mosquitoes bearing the virus, according to Japan's Kyodo News Agency.
Of the 19 infected persons, 13 are residents of Tokyo, five are from adjacent prefectures of Tokyo, and another one is from Niigata prefecture located along the coast of the Sea of Japan, Japanese Health Ministry said.
The Yoyogi park is one of the largest open spaces in central Tokyo, with plenty of people visiting there each day. Tokyo officials have now sprayed about 800 liters of pesticide throughout the park in an attempt to kill off the insects.
Japan sees around 200 cases of dengue fever every year, mostly tourists who catch the illness while traveling in tropical region. The disease, which often spreads in tropical and subtropical areas, was common in Japan during World War II but was locally eradicated for decades.