[Mechanisms of high sensitivity of Mongolian pika spp. (Pallas) to Yersinia pestis].

The regularities of the infectious process of plague in a sensible Pallas' pika species, are presented. The specific infectious process was shown to pass a number of phases. These phases are characterized by certain changes in the composition of the leukocytic pool of the peripheral blood, the immune system and the activity of the bactericidal systems of professional phagocytes. The infectious process in sensitive animals is accompanied by the formation of secondary relative immunodeficiency with a pronounced hypersuppressive component, which leads to disturbances in the cooperative interaction of immunocompetent cells; in its turn, it results in dysbalance in the cytokine system and, as a consequence, to irreversible disturbances in homeostasis, leading to the death of the infected animal.