[Analysis of the incidence of tularemia in the Breclav District 1994-1999].

Southern Moravia is one of the areas where there are long-term natural foci of tularaemia. In 1994 in the Breclav district an exacerbation of the disease was recorded in hares. During autumn hunts a positive reaction was recorded in 5.75% of examined hares. An elevated seropositivity persisted also in subsequent years and at the same time a higher human morbidity in the mentioned region. The objective of the investigation was to assess the causes and circumstances which led to the exacerbation of old known but in recent years quiescent foci in the mentioned region. To this end 350 small terrestrial mammals were examined. In one case it proved possible to detect the causal agent in Microtus arvalis. By examination of arthropods it proved possible to isolate 33 strains, i.e. 32 strains from ticks Dermacentor reticulatus and one strain from Ixodes ricinus. The results of the examination revealed that tularaemia as a classical infection with a natural focus may persist in areas where there are prerequisites for survival of the causal agent in the environment. One of the important factors of the environment are susceptible individuals (hares, small terrestrial mammals) as well as blood sucking arthropods as vectors of the disease.