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Survival and transmission of Salmonella enterica serovar Typhimurium in an outdoor organic pig farming environment

Jensen, A.N.; Dalsgaard, A.; Stockmarr, A.; Nielsen, E.M. and Baggesen, D.L. (2006) Survival and transmission of Salmonella enterica serovar Typhimurium in an outdoor organic pig farming environment. Applied and Environmental Microbiology, 72 (3), pp. 1833-1842.

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Summary

It was investigated how organic rearing conditions influence the Salmonella enterica infection dynamics in pigs and whether Salmonella persists in the paddock environment. Pigs inoculated with S. enterica serovar Typhimurium were grouped with Salmonella-negative tracer pigs. Bacteriological and serological testing indicated that organic pigs were susceptible to Salmonella infections, as 26 of 46 (56%) tracer pigs turned culture
positive. An intermittent and mainly low-level excretion of Salmonella (<100 cells per g partly explains why the bacteriological prevalence appeared lower than the seroprevalence. Salmonella persisted in the paddock environment, as Salmonella was isolated from 46% of soil and water samples (n = 294). After removal of pigs, Salmonella was found in soil samples for up to 5 weeks and in shelter huts during the entire test period (7 weeks). Subsequent introduction of Salmonella-negative pigs into four naturally Salmonella-contaminated paddocks caused Salmonella infections of pigs in two paddocks. In one of these paddocks, all tracer pigs (n = 10) became infected, coinciding with a previous high Salmonella infection rate and high Salmonella excretion level. Our results showed that pigs reared under organic conditions were susceptible to Salmonella infections
(just like conventional pigs) and that Salmonella persisting in the paddock environment could pose an infection risk. A driving force for these infections seemed to be pigs with a high Salmonella excretion level, which caused substantial contamination of the environment. This suggests that isolation of animals as soon as a Salmonella infection is indicated by clinical symptoms of diarrhea could be a means of reducing and controlling the spread and persistence of Salmonella in outdoor organic pig production environments.


EPrint Type:Journal paper
Subjects: Food systems > Food security, food quality and human health
Animal husbandry > Production systems > Pigs
Research affiliation: Denmark > DARCOF II (2000-2005) > II.10 (SaCaFree) Bacterial infection risk associated with outdoor organic pig production ...
Denmark > DTU, DFVF - Danish Institute for Food and Veterinary Research
Denmark > SOAR - Research School for Organic Agriculture and Food Systems
Deposited By: Jensen, Ms Annette Nygaard
ID Code:9158
Deposited On:31 Aug 2006
Last Modified:30 Apr 2013 20:05
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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