salmonelosis

Salmonellosis is a bacterial infection in humans caused by Salmonella species, most often presenting as gastroenteritis. It is usually associated with non-typhoidal Salmonella (NTS) serotypes, though Salmonella Typhi and Salmonella Paratyphi cause typhoid fever, a distinct illness.

Transmission occurs primarily through ingestion of contaminated food or water. Common sources include undercooked or mishandled poultry, eggs, beef, and dairy products, as well as fresh produce contaminated with animal feces. Direct contact with infected animals or person-to-person spread can also occur. The typical incubation period is about 6 to 72 hours before symptoms begin.

Clinical features range from mild to severe and usually include fever, abdominal cramps, and diarrhea, which may be watery or, less commonly, bloody. Nausea and vomiting can be present. Most illnesses are self-limited and last about 4 to 7 days, with dehydration being a concern, especially in young children and older adults. In immunocompromised individuals or those with certain underlying conditions, Salmonella can invade the bloodstream or cause focal infections, though this invasive disease is less common in healthy people.

Diagnosis is based on laboratory testing, most often stool culture. Blood cultures may be indicated in patients with fever, signs of bacteremia, or invasive disease. Molecular tests and serotyping can aid confirmation and epidemiologic tracking.

Treatment emphasizes hydration and supportive care. Most cases resolve without antibiotics; antibiotics are reserved for severe, persistent, or invasive infections, or for high-risk patients, and should be chosen based on susceptibility testing to avoid promoting resistance.

Prevention focuses on food safety and hygiene: thorough cooking of poultry and eggs, pasteurization of dairy products, avoiding cross-contamination, thorough handwashing, and proper refrigeration. Vaccines exist for typhoidal Salmonella but not for most non-typhoidal strains.