Outbreak of human Salmonella Typhimurium infections linked to contact with baby poultry from a single agricultural feed store chain and mail-order hatchery, 2009.

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.

Outbreak of salmonellosis linked to live poultry from a mail-order hatchery.

BACKGROUND: Outbreaks of human salmonella infections are increasingly associated with contact with live poultry, but effective control measures are elusive. In 2005, a cluster of human salmonella Montevideo infections with a rare pattern on pulsed-field gel electrophoresis (the outbreak strain) was identified by PulseNet, a national subtyping network. METHODS: In cooperation with public health and animal health agencies, we conducted multistate investigations involving patient interviews, trace-back investigations, and environmental testing at a mail-order hatchery linked to the outbreak in order to identify the source of infections and prevent additional illnesses. A case was defined as an infection with the outbreak strain between 2004 and 2011. RESULTS: From 2004 through 2011, we identified 316 cases in 43 states. The median age of the patient was 4 years. Interviews were completed with 156 patients (or their caretakers) (49%), and 36 of these patients (23%) were hospitalized. Among the 145 patients for whom information was available, 80 (55%) had bloody diarrhea. Information on contact with live young poultry was available for 159 patients, and 122 of these patients (77%) reported having such contact. A mail-order hatchery in the western United States was identified in 81% of the trace-back investigations, and the outbreak strain was isolated from samples collected at the hatchery. After interventions at the hatchery, the number of human infections declined, but transmission continued. CONCLUSIONS: We identified a prolonged multistate outbreak of salmonellosis, predominantly affecting young children and associated with contact with live young poultry from a mail-order hatchery. Interventions performed at the hatchery reduced, but did not eliminate, associated human infections, demonstrating the difficulty of eliminating salmonella transmission from live poultry.