Submitted to: Livestock Conservation Institute Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 6, 1995
Publication Date: N/A
Technical Abstract: Salmonella choleraesuis is a host-adapted, facultative intracellular pathogen that causes swine paratyphoid. Although S. choleraesuis is the most frequent porcine isolate, it is rarely isolated from swine feeds or nonporcine Salmonella reservoirs. This paper describes 3 experiments defining the carrier state. In one experiment the effect of intranasal (IN) or gastric (GC) route of inoculation on the carrier state was studied. Salmonella choleraesuis was recovered from a greater percentage of tissues for the IN vs. GC group at 2, 4, and 6 wk postinoculation. No differences between groups were observed at 12 wk postinoculation. In a second experiment the effect of dose of S. choleraesuis on the carrier state was studied. In this experiment, groups 1 (n=5), 2 (n=5) and 3 (n=5) were inoculated intranasally with 10**9, 10**6 and 10**3 CFU of S. choleraesuis, respectively. Group 4 (n=4) served as uninoculated control pigs. The results from this study indicated that persistence, shedding (duration and magnitude) and immune response is dose-dependent. In the third experiment, we studied the natural transmission of S. choleraesuis to naive pigs. Group 1 (Chal; n=12) was challenged with 10**8 S. choleraesuis by intranasal inoculation. One day (PI) group 2 naive pigs (Nav; n=24) were commingled with the Chal pigs. Group 3 (n=4) served as unexposed control pigs. The Chal group was shedding 2.42 log10 CFU/g feces on the day of commingling. Tonsil, nasal, rectal swabs and group fecal pools collected from individual animals indicated that Nav group pigs were shedding S. choleraesuis one day after commingling. These data indicated that naive swine exposed to swine with acute paratyphoid can be infected with and shed S. choleraesuis within 24 h of exposure.