Non-typhoidal Salmonella infections, an important cause of gastroenteritis, are mainly food borne but can be contracted through contact with reptiles and amphibians. Epidemiologists from the US Centers for Disease Control investigated a cluster of cases of gastroenteritis caused by a common strain of Salmonella typhimurium. They identified 376 cases in 44 states over 4 years, of whom 29% were hospitalised. Over two-thirds (69%) were children <10 years old. Patients or care givers were interviewed about possible exposures in the 7 days before onset. Frog exposure was reported by 61% of cases interviewed and 79% of those who knew the type reported contact with aquatic African dwarf frogs. A case control study matched cases with age-matched controls who had recent Salmonella infections but with a different strain from the outbreak strain: 67% of cases but only 3% of controls had frog exposure. Environmental samples from patients' homes and a day care centre grew isolates indistinguishable from the outbreak strain. A gastroenteritis history should include asking about frogs.
Reviewer: David Isaacs, email@example.com