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item Cray, Paula

Submitted to: International Symposium on Epidemiology and Control of Salmonella in Pork
Publication Type: Proceedings
Publication Acceptance Date: 5/4/1999
Publication Date: N/A
Citation: Gray, J.T., Cray, P.J. 1999. Detection of swine exposed to salmonella spp. International Symposium on Epidemiology and Control of Salmonella in Pork. P.46 - 50.

Interpretive Summary:

Technical Abstract: The pre-harvest detection of animals infected with Salmonella spp. Is a critical step in the reduction of this pathogen. Serological detection of Salmonella infective status can be an important tool in herd monitoring. An indirect ELISA (designated SalAD), was developed to detect antibodies in swine which have been exposed to Salmonella spp. Heat extracted surface antigens were combined from S. typhimurium (B), S. enteritidis (D1), S. anatum (E1), and S. choleraesuis (C1) representing the serogroups most often isolated from swine. Antigens were prepared using standardized extraction, purification and concentration techniques. Microtiter plates were coated with 4 ug (1 ug/serotype) of protein antigen. After blocking, swine serum was added (1:25 dilution) for 1 hr. Swine antibodies were labeled with peroxidase conjugated anti-swine IgG antibody and after adding peroxidase substrate, the absorbence was read at 450nm (410nm reference). The sensitivity of the test was evaluated against sera from experientially infected swine, long-term carrier swine, and known infected swine herds. The specificity of the test was evaluated using sera from swine free of Salmonella spp., swine which had been infected but cleared the bacteria, and swine infected with E. coli, Yersinia entercolitica or other pathogens but negative for Salmonella spp. The assay has demonstrated good sensitivity and specificity in detection infected animals and can be performed in less than three hours.