Impact of Season, Demographic and Environmental Factors on Salmonella Occurrence in Raccoons (Procyon lotor) from Swine Farms and Conservation Areas in Southern Ontario

Abstract

Salmonella has been detected in the feces of many wildlife species, including raccoons (Procyon lotor), but little is known about the epidemiology of Salmonella in wildlife living in different habitat types. Our objective was to investigate demographic, temporal, and climatic factors associated with the carriage of Salmonella in raccoons and their environment on swine farms and conservation areas. Using a repeated cross-sectional study design, we collected fecal samples from raccoons and environmental samples (soil, manure pits, dumpsters) on 5 swine farms and 5 conservation areas in Ontario, Canada once every five weeks from May to November, 2011–2013. Salmonella was detected in 26% (279/1093; 95% CI 22.9–28.2) of raccoon fecal samples, 6% (88/1609; 95% CI 4.5–6.8) of soil samples, 30% (21/69; 95% CI 20.0–42.7) of manure pit samples, and 23% (7/31; 95% CI 9.6–41.0) of dumpster samples. Of samples testing positive for Salmonella, antimicrobial resistance was detected in 5% (14/279; 95% CI 2.8–8.3) of raccoon fecal, 8% (7/89; 95% CI 3.2–15.5) of soil, 10% (2/21; 95% CI 1.2–30.4) of manure pit, and 0/7 dumpster samples. Using multi-level multivariable logistic regression analyses, we found location type (swine farm or conservation area) was not a significant explanatory variable for Salmonella occurrence in raccoon feces or soil (p > 0.05). However, detection of Salmonella in raccoon feces was associated with rainfall, season, and sex with various interaction effects among these variables. We detected a variety of Salmonella serovars that infect humans and livestock in the feces of raccoons indicating that raccoons living near humans, regardless of location type, may play a role in the epidemiology of salmonellosis in livestock and humans in southwestern Ontario.

Epidemiology of Antimicrobial Resistance in Escherichia coli Isolates from Raccoons (Procyon lotor) and the Environment on Swine Farms and Conservation Areas in Southern Ontario

“…coli and year, season, and rainfall in any of the sample types, which is in contrast to what has been found with the prevalence of Salmonella in raccoon fecal, soil and/or manure pit samples [36]. These differences might be related to the biology of these bacteria or by the small effective sample sizes for resistant E .…”

“…The Ontario Ministry of Natural Resources and Forestry issued a permit to live-trap and collect samples from raccoons in this study, and permission to work on sites was granted by the Grand River Conservation Authority, the University of Guelph, and from private land owners as appropriate. The sites, trapping and sample collection methods used in this study have been described previously [36]. Briefly, raccoons were live-trapped on five swine farms and five conservation areas from May through November, 2011–2013.…”

“…The farms were chosen based on their proximity to the University of Guelph and included farrow-to-young grower and farrow-to-finish operations. The attributes of the study sites have been described previously [36]. Three of the five farms did not administer injectable antimicrobials or antimicrobials in-feed to swine.…”

“…Environmental sample collection has been previously described [36]. Briefly, ten to twenty soil samples were collected within 2 m of where traps were placed on the first day of each trapping week at each study site.…”

Salmonellosis detection and evidence of antibiotic resistance in an urban raccoon population in a highly populated area, Costa Rica

“…This is due to the bacteria's specific resistance or more general cross‐resistance mechanisms to a variety of deleterious environmental conditions, but it is also a result of constant environmental contamination by the infected hosts, allowing for effective Salmonella expansion into new environments and new vertebrate hosts. This contamination process is associated with the type of vertebrates acting as reservoirs as well as the abiotic conditions, especially in endemic areas (Bondo et al, b; Hoelzer et al, ; Kumar, ; Murray, ; Spector & Kenyon, ).…”