Salmonella in pig farms : characterisation and epidemiological importance of the Salmonella status of gilts

The salmonella status of gilts (assessed individually and in groups) at the beginning of quarantine, as well as the evolution during quarantine were investigated by bacteriological culture of faeces and serological detection of serum antibodies against salmonella by an ELISA test. The results of the two techniques oftendisagreed and this made it difficult to choose a method with which to characterise the level of salmonella infection of a group of animals and even more so for a single animal. During quarantine a significant proportion of groups of gilts showed seroconversion. The most frequently detected serovars were S. derby and S. typhimurium. Based on the present results (frequency of isolation, serovar identification, serological status), obtained in supplier herds and in herds where the gilts will be used, the level of salmonella infection of a herd is not linked to the level of infection of its gilts, at the beginning and end of quarantine, nor the level of infection of the supplier herd.