The health ministry reported Aug. 27 that a teenager in Saitama Prefecture with no record of overseas travel had been infected with dengue fever — the first domestic infection of the disease in almost 70 years. The infection has since spread nationwide, with the number of patients reaching 133 as of Thursday.
It is now safe to assume that an outbreak of dengue fever somewhere in Japan could be possible every summer. The central and local authorities should carefully watch future developments and take necessary steps such as eliminating mosquitoes, which spread the virus, and providing information for people on how to cope with the disease.
Since 2010, about 200 Japanese were found to have been infected with dengue fever each year after traveling overseas, but infections among people with no record of traveling abroad have not been confirmed since 1945. The latest outbreak of the viral disease reflects its global spread. The number of dengue fever patients worldwide increased from some 16,000 annually in the 1960s to roughly 2 million in 2011.