title: Epidemiological investigation of an outbreak of hepatitis A at a residential facility for the disabled, 2011.
abstract: OBJECTIVE
  An outbreak of hepatitis A occurred at a residential facility for the disabled in July 10, 2011. This investigation was carried out to develop a response plan, and to find the infection source of the disease.
  
  
  METHODS
  A field epidemiologist investigated the symptoms, vaccination histories, living environments, and probable infection sources with 51 residents and 31 teachers and staff members. In July 25, 81 subjects were tested for the hepatitis A virus antibody, and specimens of the initial 3 cases and the last case were genetically tested.
  
  
  RESULTS
  Three cases occurred July 10 to 14, twelve cases August 3 to 9, and the last case on August 29. Among the teachers and staff, no one was IgM positive (on July 25). The base sequences of the initial 3 and of the last case were identical. The vehicle of the outbreak was believed to be a single person. The initial 3 patients were exposed at the same time and they might have disseminated the infection among the patients who developed symptoms in early August, and the last patient might have, in turn, been infected by the early August cases.
  
  
  CONCLUSIONS
  The initial source of infection is not clear, but volunteers could freely come into contact with residents, and an infected volunteer might have been the common infection source of the initial patients. Volunteers' washing their hands only after their activity might be the cause of this outbreak. Although there may be other possible causes, it would be reasonable to ask volunteers to wash their hands both before and after their activities.
authors.affiliation: Department of Preventive Medicine, Dongguk University College of Medicine, Gyeongju 780-714, Korea. wisewine@dongguk.ac.kr
authors.forename: Hyun-Sul
authors.initials: HS
authors.lastname: Lim
authors.forename: Kumbal
authors.initials: K
authors.lastname: Choi
authors.forename: Saerom
authors.initials: S
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000378:metabolism; D040561:Assisted Living Facilities; D002648:Child; D006233:Persons with Disabilities; D004196:Disease Outbreaks; D060766:Drinking Water / Q000821:virology; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology*; D017957:Hepatitis A Virus, Human / Q000235:genetics; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D060766:Drinking Water; D012367:RNA, Viral
keywords: Disease outbreaks; Hand disinfection; Hepatitis A; Residential facilities; Voluntary workers