PATHOGENESIS OF EXPERIMENTAL INTRA-RUMINAL INFECTIONS OF COWS WITH SALMONELLA-DUBLIN

The infectivity of a single intra-ruminal inoculation of S. dublin in cows was compared with the infectivity of a similar inoculum given as an intermittent infection. The cows were slaughtered 10 days after inoculation ceased and detailed bacteriological examinations of the alimentary tracts made. The single intra-ruminal inoculum established an active infection in the lower ileum, caecum and colon, but the intermittent inoculum was much less infective. The route of invasion of intra-ruminally administered S. dublin was studied. Following intra-ruminal administration of a single large dose of S. dublin the primary sites of bacterial penetration appeared to be the lower ileum and caecum. In these sites infection spread from the intestinal contents to intestinal wall and to the associated lymph node. Further spread to liver and spleen did not occur. © 1978.