A study of the complement fixation test in Salmonella dublin infection.

The complement fixation test was evaluated in a study of Salmonella dublin infection in cattle. In calves vaccinated with a live S dublin vaccine at three days of age, complement fixing (CF) antibodies were not detected in colostrum-fed calves although CF antibodies were detected at low titre in colostrum-deprived calves. In calves vaccinated at three months of age and in experimentally infected cows, CF antibodies persisted for three to six months but serum agglutinin (SA) antibodies persisted at diagnostic titres for longer periods. When serum samples from outbreaks of S dublin infection were examined, the CF results were in agreement with the SAT in the majority of samples obtained from adults and calves suffering from enteric disease. In samples from cases of S dublin abortion, a number of samples had negative CF titres although the SA titres were indicative of infection. Non-specific CF reactions occurred in serum samples from cattle infected with salmonella serotypes other than S dublin.