title: Outbreaks of astrovirus gastroenteritis in day care centers.
abstract: OBJECTIVE
  This study evaluated astrovirus as a cause of diarrhea outbreaks among infants and toddlers in day care centers.
  
  
  METHODS
  Stool specimens were collected weekly during four periods (from January 1986 through December 1991) from children 6 to 30 months of age who were enrolled in prospective studies of diarrhea in day care centers. All diarrheal stool specimens were tested for bacterial enteropathogens, rotavirus, enteric adenovirus, and Giardia lamblia. A total of 1365 stool specimens from 70 outbreaks in which no etiologic agent was identified and from another 11 outbreaks with a known cause were tested for astrovirus, by means of a monoclonal antibody-based enzyme immunoassay. Confirmatory testing was performed by reverse transcriptase-polymerase chain reaction with primers designed to produce an 89 base-pair product.
  
  
  RESULTS
  Astrovirus was detected in 6 (7%) of the 81 outbreaks. Of 217 children tested, 73 (34%) were infected with astrovirus; infections in 35 (48%) were symptomatic and in 38 (52%) asymptomatic. The six outbreaks lasted 11 to 44 days (median 22 days). Astrovirus excretion was detected for a duration of 2 to 30 days, with excretion occurring from 1 to 8 days (median 2 days) before diarrhea began to 1 to 20 days (median 2 days) after diarrhea ceased. Younger children (< or = 12 months) were at greater risk than older children (p = 0.011) of becoming infected with astrovirus during an outbreak and were more likely (p = 0.015) to have symptoms when infected. Of 24 specimens with astrovirus by enzyme immunoassay, 20 (83%) were confirmed to have the virus by reverse transcriptase-polymerase chain reaction.
  
  
  CONCLUSIONS
  Astrovirus was an important cause of outbreaks of diarrhea among children attending day care centers, more frequently infected younger children, and often produced asymptomatic infections.
authors.affiliation: Center for Pediatric Research, Eastern Virginia Medical School, Norfolk.
authors.forename: D K
authors.initials: DK
authors.lastname: Mitchell
authors.forename: R
authors.initials: R
authors.lastname: Van
authors.forename: A L
authors.initials: AL
authors.lastname: Morrow
authors.forename: S S
authors.initials: SS
authors.lastname: Monroe
authors.forename: R I
authors.initials: RI
authors.lastname: Glass
authors.forename: L K
authors.initials: LK
authors.lastname: Pickering
mesh_terms: D000367:Age Factors; D002656:Child Day Care Centers; D002675:Child, Preschool; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology; D003968:Diarrhea, Infantile / Q000453:epidemiology / Q000382:microbiology; D004196:Disease Outbreaks; D005759:Gastroenteritis / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D007223:Infant; D001257:Mamastrovirus; D016133:Polymerase Chain Reaction / Q000379:methods; D014777:Virus Diseases / Q000453:epidemiology*