SEASON-RELATED INCIDENCE OF YERSINIA ENTEROCOLITICA IN FECAL MATERIAL OF HEALTHY SLAUGHTERHOUSE PIGS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 244  (4) , 494-505
Abstract
From July 1976-June 1977, 1358 fecal specimens and 165 mesenteric lymph nodes of healthy slaughterhouse pigs were examined for Y. enterocolitica. The animals originated from 215 farms in 86 localities of Northern Bavaria [Germany]. Y. enterocolitica was found in fecal specimens of 371 pigs (27.3%). The 408 strains isolated included 35 from double and 1 from triple infections. Most cultures belonged to serogroups 0:6... (186 strains), 0:7... (78 strains) and 0:5... (71 strains). Serogroups 0:3 and 0:9, which in Europe are most frequently associated with human disease, were isolated from 26 animals (1.9%). Lymph nodes were positive in 2 instances (1.2%). Beside aerobic subculture on SS-agar after cold enrichment in phosphate buffered saline, anaerobic incubation was performed simultaneously during the last 8 mo. of the study. This method yielded more than twice as many isolations due to effective inhibition of oxidative bacteria (mainly Pseudomonas spp.). The incidence of asymptomatic infections was markedly related to season. The lowest incidence was observed during the summer (August 1976:0%) but increased steadily to a maximum in April 1977 (71.2%). With 1 exception, serogroups 0:3 and 0:9 were only isolated during Oct.-Dec. Despite the frequent occurrence of Y. enterocolitica in healthy pigs the significance of these animals for human yersiniosis remains unknown. The frequency of disease in infants and young children would not suggest pork as an important vehicle of transmission. The human pathogenic serogroups 0:3 and 0:9 might be simultaneously adapted to several hosts with independent cycles of infection.

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