TOKYO -- The Japanese capital's leafy Yoyogi Park boasts a running track, amphitheater, bird sanctuary, cycling course, dog run, three fountains, and it hosts a nonstop roster of festivals, concerts and flea markets, drawing over five million visitors a year, including many American tourists.
But in recent days, the 133-acre oasis has been invaded by mosquitoes carrying the dengue fever virus. The infestation has sparked Japan's first domestic outbreak of the disease in nearly 70 years, when Japanese Imperial Army soldiers brought it back from battlefields in Southeast Asia in the early 1940s. According to the Japanese Society of Travel Medicine, as many as 400,000 Japanese contracted the illness during that decade -- but eradication programs had since wiped out the malady.
Until the end of August, that is, when a few students practicing dance routines in the park suddenly experienced signs of dengue fever, which is also known as "break bone fever" for the painful symptoms it causes.
Over the last week, at least 47 more victims have appeared as far away as Osaka and Aomori, but all were bitten in or around Yoyogi. The patient list included a pair of young TV personalities who were shooting a program in the park when they were infected. All have recovered or are in stable condition.
Perhaps because the mosquitoes tend to be active during daylight hours, none of the many homeless who sleep rough in the park at night have been affected. Authorities have recommended they be moved to temporary shelters anyway, until colder weather brings the mosquito season to a close.
Yoyogi Park remains open for business, but now is dotted with warning signs, urging visitors to cover up exposed skin and apply liberal amounts of insect repellent. Park staff in white Tyvek full body suits spray foliage, fountains have been shut off, and ponds drained. While a few joggers and dog walkers still ply the quiet paths, parents and young children who used to frolic on the central lawn are staying away.
Not a single infected mosquito has been caught so far, but now white nets have been set up throughout the park to gather samples at Yoyogi, as well as at other city parks and cemeteries.
Initial optimism about a limited outbreak that would end with the first frost has now turned to unease about a disease that once afflicted only a handful of tropical countries, and now appears regularly in over 100. As many as 300 travelers bring the disease back into Japan each year, a number that has been on the rise in recent years.
Health and Welfare Minister Norihisa Tamura has said more cases could surface, but he downplayed the possibility of an epidemic, urging calm.