High diversity of Salmonella serotypes found in an experiment with outdoor pigs

Little is known about the risk of Salmonella infection in outdoor pig production, but seroprevalence data have indicated a higher incidence of Salmonella in outdoor than in conventional indoor production systems. This higher incidence may be due to an increased exposure of the animals to the surrounding environment, including contact with wildlife. In a study on the transmission of Salmonella to outdoor pigs an unexpected high diversity of Salmonella serotypes that are not normally isolated from pigs, like for instance S. Uganda and S. Goldcoast, was detected in faecal and in soil and water samples. However, in a small-scale wildlife survey to elucidate the potential source of the different Salmonella serotypes, the bacterium was not detected in any of a total of 22 rats, mice and shrews nor in 22 birds (mainly crow-birds; Corvidae). The unidentified source of the Salmonella serotypes isolated implies inadequate control possibilities and may therefore pose a problem to outdoor pig production in terms of food safety