The Japanese Ministry of Health have reported 34 cases of locally acquired Dengue fever since 1 September 2014. Dengue fever is an arbovirus spread by the Aedes aegypti species of mosquitoes which predominantly bite during the day.
All of the cases have visited Yoyogi park in central Tokyo during August 2014 and none of the cases have a recent history of overseas travel. Tokyo Metropolitan city has closed Yoyogi park and implemented control measures, including fumigation, to control mosquito breeding sites.
Advice for Travellers
Travellers to affected areas should be advised to take measures to avoid mosquito bites, particularly during daylight hours. Using DEET-based insect repellents, covering up with clothing and eliminating mosquito breeding sites (standing water) can help reduce risk.