Reptiles, amphibians, and human Salmonella infection: a population-based, case-control study.

To estimate the burden of reptile- and amphibian-associated Salmonella infections, we conducted 2 case-control studies of human salmonellosis occurring during 1996-1997. The studies took place at 5 Foodborne Diseases Active Surveillance Network (FoodNet) surveillance areas: all of Minnesota and Oregon and selected counties in California, Connecticut, and Georgia. The first study included 463 patients with serogroup B or D Salmonella infection and 7618 population-based controls. The second study involved 38 patients with non-serogroup B or D Salmonella infection and 1429 controls from California only. Patients and controls were interviewed about contact with reptiles and amphibians. Reptile and amphibian contact was associated both with infection with serogroup B or D Salmonella (multivariable odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1-2.2; P<.009) and with infection with non-serogroup B or D Salmonella (OR, 4.2; CI, 1.8-9.7; P<.001). The population attributable fraction for reptile or amphibian contact was 6% for all sporadic Salmonella infections and 11% among persons <21 years old. These data suggest that reptile and amphibian exposure is associated with approximately 74,000 Salmonella infections annually in the United States.