ABSTRACT
Objective：In August 2012, an outbreak of enterohaemorrhagic Escherichia coli (EHEC) O157 infection was investigated by the City of Sapporo and Hokkaido Prefectural Government. The initial notification reported an illness affecting 94 residents of 10 private nursing homes distributed across multiple areas of Hokkaido, the northernmost island of Japan; at this time three cases were confirmed as EHEC O157 infection. The objectives of the investigation were to identify the source of infection and recommend control measures to prevent further illness.Methods：A suspected case was defined as a resident of one of the private nursing homes in Hokkaido who had at least one of the following gastrointestinal symptoms: diarrhoea, bloody stool, abdominal pain or vomiting between 10 July and 10 September 2012. Cases were confirmed by the presence of Shiga toxin 1- and 2-producing EHEC O157 in stool samples of suspected cases. We conducted an epidemiological analysis and an environmental investigation.Results：We identified 54 confirmed and 53 suspected cases in 12 private nursing homes including five fatalities. Of the 107 cases, 102 (95%) had consumed pickles, all of which had been manufactured at the same facility. EHEC O157 isolates from two pickle samples, 11 cases and two staff members of the processing company were indistinguishable. The company that produced the pickles used inadequate techniques to wash and sanitize the vegetables.Discussion：Contaminated pickles were the likely source of this outbreak. We recommended that the processing company improve their methods of washing and sanitizing raw vegetables. As a result of this outbreak, the sanitation requirements for processing pickles were revised.
ABSTRACT
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).