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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #211001
Title: PREVALENCE OF YERSINIA ENTEROCOLITICA IN MARKET WEIGHT HOGS IN THE UNITED STATES

Author
item WESLEY, IRENE
item BHADURI, SAUMYA
item BUSH, ERIC - USDA,APHIS,FT. COLLIN,CO

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2008
Publication Date: 6/20/2008
Citation: Wesley, I.V., Bhaduri, S., Bush, E. 2008. Prevalence of Yersinia enterocolitica in market weight hogs in the United States. Journal of Food Protection. 71(6):1162-1168.

Interpretive Summary: Y. enterocolitica is a major human food-borne pathogen is one of the eight bacterial food-borne pathogens under FoodNet surveillance. Pigs are the major animal reservoir for Y. enterocolitica strains, which are potentially pathogenic for humans. In this study we wished (1) to estimate prevalence of Y. enterocolitica in hogs based on tonsil and data which we previously published for fecal samples and (2) using these data, to determine on-farm risk factors for Y. enterocolitica. We confirmed that virulent species of Y. enterocolitica are present in tonsil and fecal swabs of healthy swine with an overall on-farm prevalence of 45.1% (55 of 122 premises). Of the 40 on-farm management practices analyzed, 12 were initially identified as probable risk factors for Y. enterocolitica (p<0.25). Four factors with their accompanying odds ratio (OR) were ultimately identified in the final regression model: location in a central state was a protective factor (OR=0.3), whereas vaccination for E. coli (OR 3.0), percentage of deaths due to scours (OR 3.5), and presence of meat/bone meal in grower-finisher diet (OR 4.1) were risk factors. This is the first attempt to identify either protective or risk factors for Y. enterocolitica in the United States hog population.

Technical Abstract: Pigs are the major animal reservoir for Y. enterocolitica strains, which are potentially pathogenic for humans. The goals of this study were (1) to estimate the individual animal and on-farm prevalences of Y. enterocolitica in hogs based on tonsil samples collected during National Animal Health Monitoring System (NAHMS) Swine 2002 and (2) using these data, in addition to that previously published for fecal samples, to determine on-farm risk factors for Y. enterocolitica. Tonsil swabs (n=1,218) and fecal samples (n=2,847) were collected on farms (n=122) located in the top 17 pork producing states. Ten percent of tonsils (122 of 1,218 samples) were positive in irgasan tiracillin chlorate (ITC) enrichment broth by real-time PCR whereas 5.6% (68 of 1,218) of samples were positive after subculture to the more selective cefsulodin-irgasan-novobiovin (CIN) agar. For tonsils, the on-farm prevalence based on real-time PCR detection of the ail gene in ITC enrichments was 32% (32 of 100 premises sampled); prevalence based on subculture to CIN was 19.6% (20 of 102 premises). Results of bacteriological isolation and real-time PCR analysis of tonsils and feces were combined to estimate prevalence data (individual animal and farm), which were subsequently correlated with 40 farm management practices. Four factors with their accompanying odds ratio (OR) were identified in the final regression model: location in a central state was protective (OR=0.3), whereas vaccination for E. coli (OR 3.0), percentage of deaths due to scours (OR 3.5), and presence of meat/bone meal in grower-finisher diet (OR 4.1) were risk factors.