An autopsy of lambs that died during the first two days after birth was carried out. Typical clinical disease signs were refusal to milk, lethargy, rounded formations in the middle third part of the neck measuring 11×7×8 (cm), and death. An autopsy revealed an acute expansion and paralysis of the heart, as a result of which congested phenomena in the organs in the pulmonary circulation (pulmonary and cerebral edema) were established; hemorrhagic inflammation of the kidneys, lymphoidulitis of deep cervical and mesenteric lymph nodes, acute hemorrhagic enterocolitis. The death of the lambs was caused by heart paralysis. In the process of the autopsy, samples of pathological material (lymph nodes, heart, lungs, liver, kidneys, spleen, and brain) were taken aseptically. The samples were subjected to PCR-diagnostics and microbiological studies at the Research Laboratory of Biochemical, Molecular Genetic Research, and Breeding of Farm Animals of the Kuzbass State Agricultural Academy; they were studied for the presence of infectious agents that can be transmitted transplacentally. As a result of studies of the internal organs of lambs, the presence of the following microorganisms was established: K. pneumoniae, Chlamydiacеae spp., Mycoplasma spp. The ability of K.pneumoniae to grow under anaerobic conditions, with the production of hemolysin, was studied as well, which indicates the ability to penetrate and develop in eukaryotic cells, incl. in intrauterine conditions.