Achievements and difficulties in maintaining the tuberculosis-free status of Hungarian cattle herds.

The tuberculosis-free status of Hungarian cattle herds in the period between 1988 and the end of 1993 is evaluated. An epidemiological analysis of tuberculin tests, laboratory assays and allergic tests yielding positive results, summarized in three tables, is given with respect to the cattle population of Hungary. The origin of positive reactions obtained in the tuberculin tests was traced in different farms of a total of 323 communities. On those farms, the diagnostic slaughter and examination of 1,851 breeding animals to exclude or confirm Mycobacterium bovis infections involved substantial economic losses. From 25 outbreaks investigated in the period of study, a total of 191 M. bovis strains were isolated from the organs of 21 cattle in 15 household stocks in 14 communities, as well as from 170 bovine organ samples from large farms of 10 communities (7 agricultural co-operatives and 3 state farms). In all of these cases, infection could be traced back to humans excreting M. bovis. Determination of the 2-thiophenecarboxylic hydrazide (TCH) resistance of the isolates facilitated the epidemiological investigation. The paper also contains some recommendations on the prevention or reduction of losses.