[Development of the disease in marmot at the intranasal infection with the monkeypox virus]

In experimental study the sensitivity of the Marmota bobak species to the monkeypox virus (MPXV) with the intranasal (i/n) infection was tested. It was demonstrated that 50% of the infective dose (ID50) of the MPXV on external clinical signs of the disease was 2.2 Ig plaque forming units (PFU). The percentage of the marmot mortality is slightly dependent on the infecting dose of the MPXV, therefore it is not possible to correctly determine the value of 50 % fatal dose (FD50) for these animals. The most pronounced external clinical signs of the disease were obtained in the marmots: pox-like skin rash throughout the surface of the body and mucous membranes, purulent discharge from the nose, lymphadenitis, discoordination, tremor of the extremities, fever, increased aggression, and ruffled fur. In the course of experiments intended to determine the dynamics of the accumulation of the MPXV in various organs, tissues, and blood serum of marmot infected i/n with dose of 3.7 Ig PFU, it was found that the trachea, lungs, and the bifurcation lymph nodes are the primary target organs. The trachea, lungs, nasal mucosa membrane, and skin are the organs with maximal virus replication recorded at 5, 7, 9, and 12 days after the infection. The transfer of the MPXV into the secondary target organs (nasal mucosa membrane, brain, spleen, duodenum, adrenal glands, and skin) was carried out in marmots with lymphogenic and hematogenic ways of the dissemination of the infection.