Salmonella diffusion in a swine production system, previously identified as Salmonella-positive, was evaluated. A cohort of pigs was followed from farrowing to slaughtering. Samples of feces, intestinal content, mesenteric lymph nodes and blood were taken from the animals throughout the study. In addition, feed samples and environmental swabs were done for the isolation of Salmonella sp. Serum was submitted to a Salmonella Typhimurium LPS-ELISA. Piglets were negative in bacteriological and serological tests until the nursery phase, but became Salmonella positive in the early finishing. On this phase, 28.6% of finishers were seropositive and 75% were shedding Salmonella in feces. At slaughtering, the seropositivity (76.9%) was higher than in the early finishing, but Salmonella was isolated only from 19.2% of the sampled pigs. Two out of 26 feed samples were Salmonella positive. Contamination of the finishing site environment was detected only when the animals were housed. It was concluded that the termination phase was critical for the contamination of this cohort of pigs, being the feed a source of contamination.
swine; longitudinal study; Salmonella; ELISA
