[Statistical analysis of distribution of antibody level against Mycobacterium bovis antigens for bovine tuberculosis diagnostics].

Antibody responses to purified protein derivate PPD of tuberculin and to antigens MPB63 and MPB83 of Mycobacterium bovis were determined in bovine herd (94 adult animals). Statistical approach based on approximation by multiple Gaussians with Levenberg-Marquardt algorithm for analysis of antibody level distribution against antigens examined was provided. Our results confirm that indirect ELISA with recombinant MPB83 and MPB63 as well as conventional PPD could be used for test-systems development for detection of cow tuberculosis infection at the herd level.

[Determination of kinetic parameters lymphocyte populations in cows with chronic lymphocytic leukemia]. / Opredelenie kineticheskikh parametrov populiatsii limfotsitov korov pri khonicheskom limfolekoze.

We analyzed changes in the number of lymphocytes in the blood of cows with chronic lymphoid leukemia using the Gomperts equation of population dynamics. The parameters of this equation were determined. Coefficients beta and gamma proved to be the most variable. The former reflects the delay and the latter characterizes the maximum rate of growth of the lymphocyte population. According to these parameters, three groups of animals were distinguished with different kinetics of leucosis and different correlations between immuno-hematological indices.

Leukogenic properties of purified BLV and possible routes of its transmission with blood cells present in milk.

The results of five years studies on the possibility of experimental induction of bovine leukemia with purified BLV and different BLV-containing materials demonstrated that inoculation of calves with purified BLV (structures of 1.14-1.17 g/ml density in 20-60% sucrose gradient) can induce oncornavirus infection and bovine leukemia. From 41 experimentally infected calves 9 showed evidence of bovine leukemia. 5 of these 9 animals were from a group of 22 calves inoculated with purified BLV. Diagnosis of bovine leukemia in these 9 animals was established by hematologic (3 animals) and histologic method (6 animals). BLV was isolated from leukocytes of all of them. It was shown also that before the development of bovine leukemia the development of oncornavirus infection takes place. But only a small part of the animals with oncornavirus infection and presence of antibodies became ill with typical forms of hemoblastosis. The investigation of the role of milk and blood cells in milk in bovine leukemia transmission was also carried out. The presence was demonstrated of oncornavirus structures antigenically identical with BLV in milk and reproduction of these structures in blood cells being present in milk. These results, and also the induction of bovine leukemia, in cattle by rearing with raw milk from cattle with leukemia, allow us to suppose the possible routes of bovine leukemia transmission in nature.