Infection of ruminants by uncultivable strains of Mycobacterium avium subsp. paratuberculosis in the Czech Republic

During the survey of paratuberculosis (1992-2001) in cattle, sheep, goats and wild ruminants: red deer (Cervus elaphus), roe deer (Capreolus capreolus), fallow deer (Dama dama), and mouflon (Ovis musimon), tissue samples of the small intestine and corresponding lymph nodes of 4212 animals were examined. From total number of examined animals, Ziehl-Neelsen microscopy of organs was positive in 308 ruminants. Subsequently culture results of these animals were positive in 271 cases (88.0%). In 249 heads of cattle (Bos taurus), microscopy positive, Mycobacterium avium subsp. para tuberculosis (Map) was isolated from 226 (90.4%) animals within 1.5 to 3 months of incubation: "relatively fast-growing" strains. On the contrary, from the 59 other ruminant species 25 (42.3%) were found positive for Map within 2 and 3 months of incubation and 20 (33.8%) within 4 and 8 months of incubation: "relatively slow-growing" strains. Tissue culture of Ziebl-Neelsen positive tissue samples from gastrointestinal tract from 14 (23.7%) animals was negative in seven (50.0%) mouflons, three (21.0%) fallow deer, one (7.3%) red deer and three (21.7%) sheep (Ovis aries). Any relationship between occurrence of uncultivable Map strains and age and sex of ruminants was not revealed. From a total of 30 "relatively slow-growing" strains isolated from sheep, goats and mouflons, 13 were examined by standardised Restriction Fragment Length Polymorphism (RFLP) analysis. Four RFLP types were identified as cattle strains (n - 12): AC 10, B-C 1, B-C2, and E-C1 and one RFLP type was found in sheep strain (n = 1): C-S1. No relationship was observed among RFLP types of above mentioned 13 "relatively slow-growing" strains and 604 "relatively fast-growing" strains in our database. In our study of incubation period, also another 382 ruminants were involved. These ruminants were positive in culture of gastrointestinal tract but ZiehlNeelsen microscopy was negative in all samples.