A total of 56 people infected with the outbreak strains of Salmonella Heidelberg were reported from 15 states. Illnesses started on dates ranging from January 27, 2015 to November 25, 2017. Of those with available information:
35% of people were hospitalized. No deaths were reported.
35% of people in this outbreak are children younger than 5 years.
Epidemiologic, laboratory, and traceback investigations linked ill people in this outbreak to contact with calves, including dairy calves.
In interviews, ill people answered questions about contact with animals and foods eaten in the week before becoming ill. Of the 54 people interviewed, 34 (63%) reported contact with dairy calves or other cattle. Some of the ill people interviewed reported that they became sick after their calves became sick or died.
Surveillance in veterinary diagnostic laboratories showed that calves in several states were infected with the outbreak strains of multidrug-resistant Salmonella Heidelberg
Information collected earlier in the outbreak indicated that most of the calves came from Wisconsin. Regulatory officials in several states attempted to trace the origin of calves linked to more recent illnesses. A specific source of cattle linked to newer illnesses was not identified.