EN
The present studies were aimed at determining the relation between the findings obtained by means of serological tests and the specific molecular probe. Serological tests were performed according to the methods recommended by the Polish Ministry of Agriculture; ELISA was run with „Bioveta” and „Rhone Merieux” kits and the AGID test was performed with EBL antigen made in our laboratory. The molecular probe was prepared from the previously cloned provirus DNA of EBL virus. The EBL provirus was detected in 28 samples taken from 44 randomly selected cows in three herds on which a leukaemia eradication programme was in process. Three sera out of 28 positive reacting animals were negative in AGID test and only one serum in ELISA. The results indicate that the use of a specific molecular probe has some advantages in the diagnosis of latent virus infections. Besides, it can be applied in the studies on the pathogenesis of enzootic bovine leukaemia.