The Centers for Disease Control and Prevention (CDC), in collaboration with state departments of health and the Food and Drug Administration (FDA), is investigating an outbreak of infections caused by a type of Salmonella called Salmonella typhimurium. This infection has no relationship to typhoid fever, which is caused by another organism.

Salmonella typhimurium typically causes an illness with fever and non-bloody diarrhea which commonly resolves after about one week. This illness is different from that caused by E. coli O157:H7, which produces bloody diarrhea, severe cramps, and in some persons, severe kidney disease.

PulseNet, the network of public health laboratories that performs molecular subtyping (“DNA fingerprinting”) on bacteria that cause foodborne illnesses, has identified a specific strain of Salmonella typhimurium that has caused this outbreak. Cases caused by the specific strain have been detected regularly at low frequency (average , 86 cases per year) for the past 5 years, indicating the presence of this strain at low levels in the environment and the food chain.

The outbreak has involved 171 cases of infection by this strain in 19 states reported since September 1, 2006. The median age of patients is 36 years, and 59% are female. As with most infections caused by Salmonella , most patients had a febrile diarrheal illness. Of 73 patients for whom clinical data has been reported, 14 (19%) were hospitalized; there have been no deaths reported. At this time few new cases are being detected, and there is little evidence of continuing risk to the public.