Development of a complete ELISA using Salmonella lipopolysaccharides of various serogronps allowing to detect all infected pigs

Although poultry is recognized as the major source of food-poisoning caused by Salmonella, pork also contributes to human infections. This study was t herefore undertaken in order to develop a reliable serological method for t he evaluation of the Salmonella status of piglets. A complete ELISA was per formed using lipopolysaccharides of Salmonella Typhimurium, Anatum, Hadar a nd Infantis because these serovars were representative of the serogroups is olated from 30 contaminated fattening farms. S, Enteritidis was also added because of its importance in human infection and to include the O : 9 antig en. This method potentially detects 100% of infected pigs. A significant co rrelation was found between this serological method and the bacteriological data from mesenteric lymph nodes (p = 0.01). In addition, both sensitivity and specificity were high (97% and 94% respectively). The ELISA test was t herefore used in a cross-sectional study on 4 farms to evaluate when pigs b ecame contaminated: seropositive pigs were only found for the 20 week old f inishing pigs. The antibody response to Salmonella in piglets was also inve stigated: maternal antibodies persisted until 7 weeks of age and post-Salmo nella contamination seroconversion was detected from 8 weeks of age onwards .