Posted February 14, 2013 5:30 PM ET

 

Initial Announcement

February 14, 2013

CDC is collaborating with public health officials in many states and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) to investigate a multistate outbreak of Salmonella Heidelberg infections. Public health investigators are using DNA "fingerprints" of Salmonella bacteria obtained through diagnostic testing with pulsed-field gel electrophoresis, or PFGE, to identify cases of illness that may be part of this outbreak. They are using data from PulseNet, the national subtyping network made up of state and local public health laboratories and federal food regulatory laboratories that performs molecular surveillance of foodborne infections.

Since June 4, 2012, a total of 124 individuals infected with the outbreak strain of Salmonella Heidelberg have been reported from 12 states. Most of the ill persons have been reported from two states, Washington (56) and Oregon (38). At this time, CDC is not releasing the names of the other states until it is determined how these illnesses are linked to this outbreak.

Among 124 persons for whom information is available, illness onset dates range from June 4, 2012, to January 6, 2013. Ill persons range in age from less than 1 year to 94 years, with a median age of 23 years. Fifty-five percent of ill persons are female. Among 97 persons with available information, 31 (32%) reported being hospitalized. No deaths have been reported. Ill persons continue to be reported at lower levels in the most recent months, which may represent a “winter lull” in Salmonella infections.

The outbreak can be visually described with a chart showing the number of people who became ill each day or week. This chart is called an epi curve. Illnesses that occurred after January 6, 2013 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks. For more details, please see Salmonella Outbreak Investigations: Timeline for Reporting Cases.

Investigation of the Outbreak

Epidemiologic and traceback investigations conducted by officials in local, state, and federal public health, agriculture, and regulatory agencies indicate that consumption of chicken is the most likely source of this outbreak of Salmonella Heidelberg infections. Washington and Oregon have identified Foster Farms brand chicken as the most likely source of the infections in their states. Approximately 81% of ill persons interviewed report consuming chicken in the week before becoming ill. Investigations are ongoing to determine the specific type and source of chicken that might be linked with illness.

FSIS is currently conducting an investigation to determine the source of infections in this outbreak. CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify additional ill persons and to interview ill persons about foods eaten before becoming ill. FSIS is continuing to work closely with CDC and state partners during this investigation.

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