As of January 15, 2014, a total of 430 individuals infected with the outbreak strains of Salmonella Heidelberg have been reported from 23 states and Puerto Rico. Most of the ill persons (74%) have been reported from California. Since the last update on December 19, 2013, a total of 14 new ill persons have been reported from four states: Arizona (1), California (11), Idaho (1), and Virginia (1).

Most of the ill persons (74%) have been reported from California. The number of ill persons identified in each state is as follows: Alaska (1), Arkansas (1), Arizona (19), California (321), Colorado (9), Connecticut (1), Delaware (1), Florida (4), Idaho (5), Illinois (1), Kentucky (1), Louisiana (1), Michigan (3), Missouri (5), North Carolina (1), Nevada (10), New Mexico (2), Oregon (10), Puerto Rico (1), Texas (10), Utah (2), Virginia (4), Washington (16), and Wisconsin (1).

Among 418 persons for whom information is available, illness onset dates range from March 1, 2013 to December 26, 2013. Ill persons range in age from less than 1 year to 93 years, with a median age of 18 years. Fifty-two percent of ill persons are male. Among 359 persons with available information, 137 (38%) reported being hospitalized. Thirteen percent of ill persons have developed blood infections as a result of their illness. Typically, approximately 5% of persons ill with Salmonella infections develop blood infections. No deaths have been reported.

The number of reported infections from the outbreak strains of Salmonella Heidelberg has returned to baseline levels indicating that this particular outbreak appears to be over. However, activities related to this investigation are ongoing. Illnesses that occurred after December 15, 2013, might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported.

Epidemiologic, laboratory, and traceback investigations conducted by local, state, and federal officials indicate that consumption of Foster Farms brand chicken is the likely source of this outbreak of Salmonella Heidelberg infections.

The outbreak strains of Salmonella Heidelberg are resistant to several commonly prescribed antibiotics. Although these antibiotics are not typically used to treat Salmonella bloodstream infections or other severe Salmonella infections, antibiotic resistance can increase the risk of hospitalization in infected individuals.