title: Carrier prevalence, secondary household transmission, and long-term shedding in 2 districts during the Escherichia coli O104:H4 outbreak in Germany, 2011.
abstract: BACKGROUND
  From May through July 2011, Germany experienced a large outbreak of Shiga toxin-producing Escherichia coli (STEC) O104:H4 infection. Our objective was to identify the prevalence of STEC O104:H4 carriers in households in highly affected areas, the rate of secondary household transmissions, and the duration of long-term shedding.
  
  
  METHODS
  In a cross-sectional study, we recruited case and control households to determine STEC household prevalence. We then conducted a prospective cohort study (households with ≥ 2 members and ≥ 1 case) to determine rates of household transmission and shedding duration.
  
  
  RESULTS
  For part 1, we recruited 57 case households (62 case patients and 93 household contacts) and 36 control households (89 household members). We only detected cases in previously known case households and identified 1 possible adult-to-adult household transmission. For part 2, we followed 14 households and 20 carriers. No secondary household transmission was detected in the prospective follow-up period. In 1 adult carrier, shedding lasted >7 months. However, the median estimated shedding time was 10-14 days (95% confidence interval, 0-33 days). Three carriers showed intermittent shedding.
  
  
  CONCLUSIONS
  The prevalence of STEC O104:H4 carriers even in highly affected areas appears to be low. Despite prolonged shedding in some patients, secondary adult-to-adult household transmissions seem to be rare events in the postdiarrheal disease phase.
authors.affiliation: Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany. Abu-SinM@rki.de
authors.forename: Muna Abu
authors.initials: MA
authors.lastname: Sin
authors.forename: Anja
authors.initials: A
authors.lastname: Takla
authors.forename: Antje
authors.initials: A
authors.lastname: Flieger
authors.forename: Rita
authors.initials: R
authors.lastname: Prager
authors.forename: Angelika
authors.initials: A
authors.lastname: Fruth
authors.forename: Erhard
authors.initials: E
authors.lastname: Tietze
authors.forename: Eckhart
authors.initials: E
authors.lastname: Fink
authors.forename: Jutta
authors.initials: J
authors.lastname: Korte
authors.forename: Susanne
authors.initials: S
authors.lastname: Schink
authors.forename: Michael
authors.initials: M
authors.lastname: Höhle
authors.forename: Tim
authors.initials: T
authors.lastname: Eckmanns
mesh_terms: D000328:Adult; D002353:Carrier State / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D004196:Disease Outbreaks; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000635:transmission*; D005191:Family Characteristics; D005260:Female; D006463:Hemolytic-Uremic Syndrome / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D054323:Shiga-Toxigenic Escherichia coli; D055815:Young Adult