Salmonella carriage in an Irish pig herd: correlation between serological and bacteriological detection methods

Salmonella carriage in pigs represents a serious health problem that undoubtedly contributes to the spread of human disease. Thus, the efficient and reliable testing of farm animals for bacteria such as Salmonella is an important aspect of any efficient control strategy. Serological analysis of 15 meat juice samples detected antibodies against Salmonella in some, but not all, of the animals identified bacteriologically as harboring the pathogen, indicating a lack of correlation between the bacteriological and serological methods used for Salmonella detection. The results suggest that testing by enzyme-linked immunosorbent assay is appropriate at the herd level, with culture methods preferable for individual animal analysis. A novel culture protocol detected Salmonella in the cecal contents of 15 pigs, whereas a method based on the European Standard identified only 9 pigs as being Salmonella-positive. During the study, an unusual finding was the relatively high incidence of Salmonella London carriage in the pigs tested.