[Self-maintenance of foci of bovine leptospirosis].

The relationship between the rate of cattle infection with leptospirosis and the total number of livestock at cattle-breeding farms has been established. The annual dynamics of this infection has been found to give two morbidity rises among the animals, occurring not due to their contacts with the natural foci of leptospirosis, but as a consequence of the animal vertical and horizontal "circulation". The mechanisms of self-maintenance of the foci of leptospirosis among cattle are discussed.