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Salmonellosis is an illness caused by the bacterium Salmonella enterica. While more than 2,460 serotypes of S. enterica have been identified, serotypes Enteritidis (S. Enteritidis) and Typhimurium (S. Typhimurium) have accounted for the majority of human infections in recent years. All Salmonella spp. serotypes can be considered zoonoses, with the exception of S. Typhi and S. Paratyphi which are species-specific for humans.

Salmonellosis in humans presents as acute enterocolitis with sudden onset of headache, abdominal pain, diarrhoea, nausea and occasionally vomiting. Fever almost always occurs, while severe dehydration can occur in vulnerable people such as infants, the immunocompromised and the elderly. In a minority of cases, reactive arthritis (Reiter’s syndrome) follows gastroenteritis. Salmonella spp. can be transmitted to humans via contaminated food (both animal and plant) or by direct contact with infected animals or people. A range of domestic and wild animals act as reservoirs for Salmonella spp.. Humans can also act as reservoirs, although chronic carriage is rare.

View our factsheet on Salmonella species