From 20 cattle herds infected with paratuberculosis, 2 906 samples of the external environment were examined, and 57 (2.0%) tested positive for M. avium subsp. paratuberculosis. RFLP types of these strains were always the same to RFLP types isolated form animals residing in the same locality. In an infected farm a 2 years study was carried out to assess the persistent of M. paratuberculosis in slurry. The identified RFLP type was not changed in 10 months. M. paratuberculosis was isolated from non-vertebrates 1 (3.0%) from 33 samples of worms, 78 (22.2%) from 351 larvae of drone flies (Eristalis tenax) and 4 (2.0%) from 202 samples of dipterous flies of the family Scatophagidae (Scatophaga sp.) and Calliphoridae (Calliphora vicina and Lucillia caesar). RFLP types of isolated strains were identical with RFLP types from infected ruminants in the respected farms. For other possible spread of M. paratuberculosis, vegetables were cultivated (lettuce, radish, tomato) four weeks on soil artificially infected by suspension of M. paratuberculosis of RFLP type B-C1 usually isolated from ruminants and the environment. Identical strains of RFLP types were isolated from the root, stem, leaf, radish and tomato. Non-vertebrates (Lumbricus terrestris, Blatta orientalis, Tenebrio molitor, Zophobas atratus) were infected with M. paratuberculosis of RFLP type B-C1 suspension isolated from cows' faeces. Shedding of the organism in faeces of non-vertebrates was detected until 72 hours after infection. Long term persistence of the infectious agent, however was not found. In view of possible significance of the diseases paratuberculosis control programme should respect a stringent hygiene and thorough sanitation practice including disinfection and disinfestation of stables and holding areas.

Supported by the grants No. QLK2-CT-2000-00928 (Sacrohn, Brussels, EC) and QD1191 (MAgr., Czech Republic).