Prevalence of antibodies to Yersinia enterocolitica O:3 among Norwegian military recruits: association with risk factors and clinical manifestations.

IgG antibody activity to Yersinia enterocolitica serogroup O:3 was detected in sera from 56 (7.4%) of 755 Norwegian military recruits, using an enzyme-linked immunosorbent assay. The highest prevalence was found among recruits from Oslo city (12/56, 21.4%). The recruits answered a questionnaire which covered demographic data, specific exposures, and clinical information. The following risk factors were found to be independently associated with IgG activity in logistic regression analysis: receiving drinking water from a private well (odds ratio (OR) = 3.40; p = 0.004), being a resident of Oslo city (OR = 2.99; p = 0.006), and living in eastern Norway (OR = 2.25; p = 0.015). By univariate analysis, living in an urban area was associated with IgG activity, but this factor did not independently affect risk. Present or previous contact with animals, including pigs, and travels abroad were not associated with an increased risk. Yersinia enterocolitica O:3 seropositive recruits were more likely to report previous surgery for suspected appendicitis than seronegative individuals (OR = 4.26; p = 0.0024). Among recruits with previous appendectomy, mesenteric lymphadenitis as the sole peroperative finding was more common in patients with IgG activity to Y. enterocolitica O:3 (4/7) than in seronegative patients (1/19) (p = 0.01). Recurrent diarrhea, steatorrhea or joint complaints were not associated with antibody activity.