A multi-state investigation with over two dozen states and the U.S. Centers for Disease Control and Prevention has yet to identify the source of an outbreak of Salmonella Typhimurium. Cases, some of which date back to October 2008, match each other by their DNA fingerprint (PFGE) and appear to have a common origin, the CDC said. In all, there are 336 cases nationwide have the same PFGE.

But, no source? Go figure.

Salmonella Typhimurium is a leading cause of human gastroenteritis. The genus Salmonella contains over 2,000 sero-species and is one of the most important pathogens in the family Enterobacteriaceae. Salmonella are Gram-negative, anaerobic bacteria of the family Enterobacteriaceae, made up of nonspore-forming rods, usually motile by flagella. Salmonella enterica serovar Typhimurium is the among the most common Salmonella serovars causing Salmonellosis infections in the US. In humans, Salmonellosis causes diarrhea, fever, and abdominal cramps 12 to 72 hours after infection and may last for up to 7 days. Some cases result in hospitalization. Some in death. Salmonella is readily transmitted through the faeces of people or animals.