Serological evidence for the presence of antibodies to Salmonella typhi among slaughtered pigs, goats and sheep.

A serological search for healthy carriers of S. typhi was undertaken among regularly slaughtered pigs, goats and sheep. Serum samples from 49 pigs, 40 goats and 35 sheep were tested for the presence of antibodies to S. typhi by the tube agglutination (TAG) and indirect haemagglutination (IHA) methods. Of the 49 pig sera screened, a total number of 39 cases were positive, of which 27 were positive by both IHA and TAG methods, and 12 one test only. Twenty-two of the pig sera but none of the sheep and goat sera were positive at higher titre. These findings suggest that pigs may harbour S. typhi and may act as carriers in transmitting infection to man.