DEVELOPMENT AND APPLICATION OF ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR SPECIFIC DETECTION OF SALMONELLA-ENTERITIDIS INFECTIONS IN CHICKENS BASED ON ANTIBODIES TO SEF14 FIMBRIAL ANTIGEN

A double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) w as developed to detect antibodies to the SEF14 fimbrial antigen (SEF14 -DAS ELISA) and was evaluated for its use in the specific detection of chicken flocks infected with Salmonella enteritidis, The SEF14-DAS EL ISA successfully discriminated between chickens experimentally infecte d with S, enteritidis and those infected with S. panama or S. typhimur ium, although the SEF14 responses in adult birds infected with S. ente ritidis were detectable but low, In contrast, ELISAs used to detect an tibodies to lipopolysaccharide (LPS) and flagella were unable to discr iminate between the infected groups of chicks and adult birds infected with different Salmonella serotypes, LPS and flagellar responses were low and variable in chicks, whereas in adult hens they were found to be consistently strong, When flocks naturally infected with S. enterit idis were tested by the SEF14-DAS ELISA and ELISAs to detect LPS and f lagellar antibodies, it was found that they could all identify the inf ected flocks, although there was little correlation between individual serum samples, The study shows that the SEF14-DAS ELISA may offer adv antages over existing assays with comparable sensitivities coupled wit h higher specificities for the serological detection of S. enteritidis -infected chicken flocks.