According to the Centers for Disease Control and Prevention (CDC), there are at least 40,000 proven cases of salmonellosis in the United States each year. Although there are hundreds of different subspecies (serovars) of salmonella, Salmonella Typhimurium (ST) received significant media attention in 2008 and 2009 as the pathogen was implicated in contaminated peanut butter products that were distributed to schools, nursing homes and snack food manufacturers.
Common Symptoms of ST
According to the World Health Organization, in most cases, ST produces mild, self-limited gastroenteritis with classic symptoms of fever, stomach cramps, nausea, vomiting and diarrhea. Symptoms begin 12 to 72 hours after ingestion of the contaminated food or beverage and persist for four to seven days. Young children, the elderly and people with chronic medical problems may require hospitalization, usually for dehydration. According to the CDC, antibiotic treatment is required in less than 2 percent of cases. Although ST outbreaks were identified with contaminated peanut products, salmonellosis usually occurs as isolated cases and may be difficult to distinguish from viral gastroenteritis. ST does not cause typhoid fever, which is caused by the similarly named Salmonella Typhi.
Uncommon Symptoms of ST
According to the World Health Organization, in rare cases, ST escapes the intestine to enter the bloodstream. Bloodstream infection may itself be fatal. Symptoms of bloodstream infection include high fever, altered mental status and shaking chills. ST can also produce long-term complications it leaves the bloodstream to infect other areas of the body. Long-term complications of ST infections include infection of the heart valves and lining of the heart (endocarditis), brain abcess, infection of the bone (osteomyelitis) and Reiter's Syndrome, an autoimmune disease that produces joint pain, eye irritation and problems with urination. Almost all cases occur in immunocompromised people (AIDS, cancer and sickle cell anemia) or people with multiple medical problems.
Sources of ST Infection
Salmonella is considered a "zoonotic infection," meaning that it is primarily acquired from infected animals, which may exhibit no signs of illness. Unlike other salmonella subspecies, such as Salmonella Enteridis, which is almost exclusively associated with undercooked eggs, ST outbreaks have been linked to a variety of meats and meat products---especially sausage and hamburger meat---and unpasteurized dairy products, in addition to eggs and poultry. ST may also be acquired from the feces of dogs, cats, turtles and frogs. The risk is particularly high with turtles and frogs. These animals should not be kept as pets in homes with children under 5, elderly people or people with other medical problems, especially HIV/AIDS. The Web site Foodsafety.gov represents the collaborative efforts of the CDC, the United States Department of Agriculture, the Food and Drug Administration and other government agencies to provide the latest information and resources on food safety, including information on salmonella recalls.
