RESUMO
BACKGROUND: Over 30 outbreaks of human salmonellosis linked to contact with live poultry from mail-order hatcheries were reported to Centers for Disease Control and Prevention between 1990 and 2010. In May 2009, we investigated an outbreak of human Salmonella Typhimurium infections, primarily affecting children. METHODS: A case was defined as a person with the outbreak strain of Salmonella Typhimurium, as determined by pulsed-field gel electrophoresis and multiple-locus variable-number tandem repeat analysis, in a Pennsylvania or New York resident with illness onset between May 1 and September 1, 2009. We conducted a case-control study to examine the relationship between illness and live poultry contact. Controls were age-matched and geographically-matched. Traceback and environmental investigations were conducted. RESULTS: We identified 36 case-patients in Pennsylvania and New York; 36% were children aged ≤5 years. Case-patients were more likely than controls to report live baby poultry contact (matched odds ratio [mOR]: 17.0; 95% confidence interval [CI]: 2.7-710.5), contact with chicks (mOR: 14.0; 95% CI: 2.1-592.0), ducklings (mOR: 8.0; 95% CI: 1.1-355.0) and visiting agricultural feed stores (mOR: 6.0; 95% CI: 1.3-55.2). Most (83%) visited agricultural Feed Store Chain Y, a national agricultural feed store chain, which received poultry from Hatchery C, which is supplied by multiple egg sources. Salmonella Typhimurium was isolated from a source duck flock, but had a different pulsed-field gel electrophoresis pattern than the outbreak strain. CONCLUSIONS: Live baby poultry remain an important source of human salmonellosis, particularly among children. Preventing these infections requires comprehensive interventions at hatcheries and agricultural feed stores; pediatricians should inform patients of risks associated with live poultry contact.