An outbreak of Salmonella Typhimurium has spread to 42 states in the US, with almost 400 people infected by the bacteria and up to 20% of the victims requiring hospitalization.[social_buttons]

The CDC, in conjunction with the USDA, the FDA and the Food Safety and Inspection Service (FSIS), is investigating the multi-state outbreak. The illnesses were said to have begun between September 3 and December 29, 2008, with most illnesses beginning after October 1.

Those infected with salmonella experience fever, diarrhea, and abdominal cramping about 12 to 72 hours after infection. The illness usually lasts anywhere from four to seven days. The list of states and possible foods involved have not yet been released.

According to the FDA, “Most types of Salmonella live in the intestinal tracts of animals and birds and are transmitted to humans by contaminated foods of animal origin. Salmonella can silently infect the ovaries of healthy-appearing hens and contaminate the eggs before the shells are formed.

Because an outbreak from a widely distributed product causes illnesses across the nation, the identification of the source of the contamination is often difficult. It typically takes weeks and is not always successful.

Only after a source is identified will public health officials then advise the public to avoid it, and conduct recalls when appropriate.

CDC officials recommend protecting yourself from a salmonella infection with frequent handwashing, especially when handling meat or eggs, and thoroughly cooking your food.

Image of salmonella typhimurium invading cells: Nutloaf at Flickr under Creative Commons