A five-year survey of human Yersinia enterocolitica infections in Hungary.

Human infections associated with Yersinia enterocolitica in Hungary in the years 1969-1974 have been surveyed. During this period the public health laboratory network isolated 1355 strains from 1096 persons. The number of isolates according to sero-groups was: 1343 O3, 6 O9, 2 O1, 2a, 3 and 1 strain for O5, O6, O1O and O15 each. (ii) A total of 2192 serum specimens from patients gave positive agglutination reaction with antigen O3 in 26.8%, with antigen O9 in 3.2%. (iii) Fifty-six per cent of bacteriologically positive persons had enteritis. Other clinical forms (pseudoappendicitis and other abdominal complaints, erythema nodosum, rheumatoid arthritis) were encountered in O 1-2.7%. Symptomless excreters of Y. enterocolitica amounted to 23.1% of all positive persons. (iv) Patients with enteritis and symptomless excreters were rather evenly distributed between 10 and 60 years of age; 1--9-year-old children were affected more frequently (47.7% of all positive persons). Six distribution was, males: females = 1.5 : 1. In seasonal incidence yersiniosis differed from other enteric diseases: it showed a peak in the autumn-winter months. Sporadic cases and family outbreaks were the most frequent; epidemic infections in nurseries were also recorded. (v) Out of 59 animal strains 39 group O3 cultures were isolated from pigs, which may be assumed as the most important reservoir of yersinosis in Hungary.