Prevalence of E. coli O157:H7 and Salmonella in wildlife from the central coastal counties of California

We tested fecal samples using anal swabs or colons from 86 wildlife species for Escherichia coli O157:H7 (N = 3,149) and Salmonella (N = 1,706). All Canada geese (Branta canadensis) were negative for E. coli O157:H7 (N = 469)... [ view full abstract ]

We tested fecal samples using anal swabs or colons from 86 wildlife species for Escherichia coli O157:H7 (N = 3,149) and Salmonella (N = 1,706). All Canada geese (Branta canadensis) were negative for E. coli O157:H7 (N = 469) and Salmonella (N = 220). All small rodents were negative for E. coli O157:H7 (N = 920) and 3.6% (N = 557) were positive for Salmonella. One (0.11%) bird (N = 924) was positive for E. coli O157:H7 and 2.3% (N = 565) were positive for Salmonella. All black-tailed deer (Odocoileus hemionus columbianus) were negative for E. coli O157:H7 (N = 447) and 2.3% (N = 178) were positive for Salmonella. Three (2.0%) tule elk (Cervus canadensis nannodes) were positive for E. coli O157:H7 (N = 150) and three (3.8%) (N = 78) were positive for Salmonella. The non-native wild pig (Sus scrofa) had the highest prevalence, 5.0% (N = 239) and 5.6% (N = 108) for E. coli O157:H7 and Salmonella, respectively. E. coli O157:H7 was negative in almost all native wildlife, indicating that food contamination risk is low. The highest prevalence was from the wild pig, which may indicate a higher risk from these species. Salmonella was detected in a larger diversity of avian and mammalian species and may indicate that under certain high density situations the food safety risk is more elevated if these species are in close proximity to produce fields. The house mouse, black rat, and wild pig are non-native species to North America, thus, their removal will not impact native species. We recommend other pathogenic strains associated with outbreaks of fresh produce (e.g. non-O157 Shiga toxin producing E. coli, Campylobacter, Listeria) be included in future studies. We recommend big game, bird species that form large density flocks around agricultural facilities and goose studies be continued.