Prevalence of Pathogenic Yersinia enterocoliticain Finnish Slaughter Pigs

The prevalence of human pathogenic Yersinia enterocoliticawas determined in tonsil and intestinal content samples from 388 healthy fattening pigs at the four biggest Finnish slaughterhouses. These slaughterhouses process 73% of pigs in Finland. Tonsil samples were tested by PCR targeted for yadA, and intestinal samples were cultured. All pathogenic Y. enterocoliticaisolates represented bioserotype 4/O:3. The prevalence of Y. enterocoliticain tonsil samples was 60% (95% confidence limit, 55.4 to 65.1%), and its prevalence in intestinal samples was 26% (95% confidence limit, 22.1 to 31.2%). The prevalence of Y. enterocoliticain tonsil and intestinal samples varied between the four slaughterhouses. The tonsil prevalence of Y. enterocoliticawas higher in slaughterhouse B, and the prevalence in intestinal content was higher in slaughterhouse C. There were more positive results in both tonsil and intestinal samples in pigs coming from fattening farms than in pigs coming from farrowing-and-fattening farms. A seasonal variation was observed in the prevalence of Y. enterocoliticain intestinal samples, with the highest prevalence during July and August, but no seasonal variation was detected in tonsil samples.