Less than a week ago, in Japan Reports 1st Locally Acquired Dengue Case In 60 Years, we learned of a teenage girl (without recent travel history outside the country), living in Saitama prefecture (near Tokyo) who had been diagnosed with Dengue fever.
This marks Japan’s first locally acquired case of the mosquito-borne virus since the 1940s (although a German tourist came home from a trip to Japan with Dengue in 2013).
In less than six days the number of Dengue cases reported from Japan has jumped to 34, with nearly all of them associated with recent visits to the popular Tokyo destination Yoyogi Park (once part of the 1964 Olympic Village) , which is adjacent to the Harajuku railway station and Meiji Shrine in Shibuya.
September 02, 2014
THE ASAHI SHIMBUN
Health ministry officials announced on Sept. 2 that 12 more cases of dengue fever have been confirmed from mosquitoes at Tokyo's Yoyogi Park, with the outbreak spreading farther across the country.
The latest patients reside in Tokyo, Osaka, Aomori and Yamanashi prefectures. Like the 22 other cases already confirmed, the 12 individuals have not gone abroad recently, but have visited Yoyogi Park in Shibuya Ward and its vicinity.
While having a common, geographically-limited source may make eradicating their infected mosquitoes easier, the danger exists that visitors to the park either have, or will carry the virus to infect other mosquito populations in Japan.
We’ll know that has happened if cases not associated with Yoyogi Park begin to emerge.
While dengue infected mosquitoes may not survive Japan’s winter, the yearly influx of millions of tourists – many from regions of the world where Dengue is endemic – all but assures the virus will be re-introduced to Japan’s mosquito population in the future.
The World Health Organization estimates 100 million people are infected with Dengue each year, and 500,000 are sickened enough to require hospitalization. The WHO considers Dengue to be the most rapidly spreading mosquito borne viral disease in the world, and that increasingly it is posing a threat to both Europe and North America.
Countries at risk for Dengue Transmission
For more on the spread of Dengue around the world you may wish to revisit these recent blogs: