1170. Secondary Household Transmission Associated with Shiga toxin-producing Escherichia coli Outbreaks in Japan
Session: Poster Abstract Session: Public Health
Friday, October 9, 2015
Room: Poster Hall
  • 1170.pdf (148.3 kB)
  • Background: In Japan, all cases of Shiga toxin-producing Escherichia coli (STEC) infection are notifiable and 3000-4000 patients with STEC infection have been reported annually since 1999. Secondary household transmission (SHT) of STEC infection has been reported from outbreaks occurred in various institutions such as restaurants, elderly facilities and day-care centers (DCCs). If STEC is brought each home from DCCs, it might pose a high risk of hemorrhagic enteritis with serious complications, such as hemolytic uremic syndrome, to a great number of family members. Therefore, prevention of SHT is important during the early period in STEC outbreaks. The aim of this study was to reveal the precise picture of SHT due to STEC outbreaks in DCCs.

    Methods: To detect suspected outbreaks occurred at DCCs, the regions where 10 or more STEC-infected children aged 0-6 years were reported in 2006 were identified from the National Epidemiological Surveillance of Infectious Disease (NESID). Questionnaires were sent to local health centers (LHCs) that may have responded to the outbreaks. Based on the results of questionnaires and the NESID data, the SHT rates were calculated from various perspectives.

    Results: By the retrospective cohort study, sixteen outbreaks were detected. The median SHT rate was 4.4% (range 0.0-34.4%). The highest rate was 23.0% among children aged 6-9 years. The highest rate for different family members was 21.3% in brothers, following 18.3% in sisters, 10.0% in mothers. The SHT rate of mothers were significantly higher than that of fathers and grandparents. The SHT rate was highest when DCC children were aged 6 years. Both the SHT rate and the incidence of gastroenteritis significantly tended to increase at a younger age (p <0.001). The group infected by the Stx1 and Stx2-producing STEC O157 strain showed higher SHT rate than that infected by the Stx1-producing STEC O26 strain without significant difference (10.8% and 8.7%, respectively).

    Conclusion: The SHT rate was relatively higher in brothers, sisters and mothers. Hygiene education should be emphasized for children aged 6-9 years as well as younger children. Education about infection prevention should be provided to families in consideration of the family structure and the level of contact with children for each family member.

    Koichi Tokuda, MD, PhD, MPH, Department of Infection Control and Prevention, Division of Medical and Environmental Safety, Kagoshima University Hospital, Kagoshima, Japan, Yuichiro Yahata, MT, PhD, MPH, National Institute of Infectious Diseases, Tokyo, Japan and Tomimasa Sunagawa, MD, PhD, Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan


    K. Tokuda, None

    Y. Yahata, None

    T. Sunagawa, None

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