title: Enterohemorrhagic Escherichia coli outbreaks related to childcare facilities in Japan, 2010-2013.
abstract: BACKGROUND
  Enterohemorrhagic Escherichia coli (EHEC) is an important cause of gastroenteritis in Japan. Although non-O157 EHEC infections have been increasingly reported worldwide, their impact on children has not been well described.
  
  
  METHODS
  We collected national surveillance data of EHEC infections reported between 2010 and 2013 in Japan and characterized outbreaks that occurred in childcare facilities. Per Japanese outbreak investigation protocol, faecal samples from contacts of EHEC cases were collected regardless of symptomatic status. Cases and outbreaks were described by demographics, dates of diagnosis and onset, clinical manifestations, laboratory data, and relation to specific outbreaks in childcare facilities.
  
  
  RESULTS
  During 2010-2013, a total of 68 EHEC outbreaks comprised of 1035 cases were related to childcare facilities. Among the 66 outbreaks caused by a single serogroup, 29 were serogroup O26 and 22 were O157; 35 outbreaks were caused by stx1-producing strains. Since 2010, the number of reported outbreaks steadily increased, with a rise in cases and outbreaks caused by stx1-producing O26. Of 7069 EHEC cases reported nationally in 2010-2011, the majority were caused by O157 (n = 4938), relative to O26 (n = 1353) and O111 (n = 195). However, relative to 69 cases of O157 (2%) associated with childcare facility EHEC outbreaks, there were 131 (10%) such cases of O26, and this trend intensified in 2012-2013 (O157, 3%; O26, 24%; O111, 48%). Among family members of childcare facility cases, the proportion of cases that were symptomatic declined with age; 10/16 cases (63%) aged 6 years or younger, 16/53 cases (30%) 6-19 years old, 23/120 cases (19%) 20-49 years old and 2/28 cases (7%) 50 years or older were symptomatic. Thirty one of the 68 outbreaks (46%) were classified as foodborne-related.
  
  
  CONCLUSIONS
  Childcare facility EHEC outbreaks due to non-O157 serogroups, particularly O26 and O111, increased during 2010-2013. These facilities should pay extra attention to health conditions in children. As older family members of childcare facility cases appear to be less symptomatic, they should be vigilant about hand-washing to prevent further transmission.
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. akanay@nih.go.jp.|Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan. akanay@nih.go.jp.
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Kanayama
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. yahata@nih.go.jp.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Yahata
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. arima@nih.go.jp.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Arima
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. takuri@nih.go.jp.
authors.forename: Takuri
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. saitou@nih.go.jp.
authors.forename: Takehito
authors.initials: T
authors.lastname: Saitoh
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. kanou@nih.go.jp.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kanou
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. kkawa@nih.go.jp.
authors.forename: Kunio
authors.initials: K
authors.lastname: Kawabata
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. sunatomi@nih.go.jp.
authors.forename: Tomimasa
authors.initials: T
authors.lastname: Sunagawa
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. djyu@nih.go.jp.
authors.forename: Tamano
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. oishik@nih.go.jp.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Oishi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002656:Child Day Care Centers; D002675:Child, Preschool; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D054324:Enterohemorrhagic Escherichia coli / Q000145:classification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000821:virology*; D005243:Feces / Q000821:virology; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology / Q000821:virology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D065288:Serogroup; D055815:Young Adult