In late August 2014, three autochthonous dengue cases were reported in Japan. Since then, as of 17 September 2014, a total of 131 autochthonous cases have been confirmed. While cases were reported from throughout Japan, the majority were linked to visiting a large park or its vicinity in Tokyo, and the serotype detected has been serotype 1. We report preliminary findings, along with the public health response activities, of the first documented autochthonous dengue outbreak in Japan in nearly 70 years.Dengue is an acute, mosquito-borne febrile illness caused by a flavivirus found widely in the Asia-Pacific region, particularly in South-East Asia. While the most competent mosquito species for dengue virus transmission is believed to be Aedes aegypti, Aedes albopictus is also a competent vector present in much of Japan during the warmer months. Infection with dengue virus may cause fever, headache, muscle pain and/or rash but may also be mild or asymptomatic. While there is no specific treatment, with early and appropriate medical care, the likelihood of infections resulting in severe forms or death is rare. In Japan, dengue has been a notifiable disease since April 1999. Physicians are required to report demographic, clinical and exposure history information of laboratory-confirmed cases to the local public health centre that are then reported to the Ministry of Health, Labour and Welfare (MHLW) and the National Institute of Infectious Diseases (NIID).

Since late 2013 through March 2014, Japan experienced a rapid rise in measles cases. Here, we briefly report on the ongoing situation and share preliminarily findings, concerns and challenges and the public health actions needed over the coming months and years.

Measles is a notifiable disease in Japan based on nationwide case-based surveillance legally requiring physicians to report all clinically diagnosed and laboratory-confirmed cases within seven days, but preferably within 24 hours. After a large outbreak in 2007–2008 (more than 11 000 cases reported in 2008 alone) and a goal of elimination by April 2015, a catch-up programme using the bivalent measles-rubella (MR) vaccine was offered for grades seven and 12 (ages 12–13 and 17–18 years) from April 2008 through March 2013. During this period, there was an estimated 97% decline in measles notifications, and the cumulative number of reported cases has been steadily declining over the last five years (732 cases in 2009, 447 cases in 2010, 439 cases in 2011, 293 cases in 2012 and 232 cases in 2013). However, since late 2013 through March 2014, the country experienced a resurgence only a year after a large rubella outbreak.