The review considers wild animal coronaviruses that live in Russia and present certain epidemic and epizootic risks. It is believed that coronaviruses entered the human population from representatives of the wild fauna and bats (the main hosts are natural reservoirs), as well as snakes, pangolins, civets, camels (intermediate hosts) are proposed as candidates. Meanwhile, this list is much wider and the intermediate link may be feline (tigers, leopards, Pallas’s cats, caracals, European wildcat and eurasian lynxs), mustelidae (american minks, ferrets and siberian weasel), rodents (mice and rats), marine mammals (harbour seal, bottlenose dolphin and beluga whale), as well as insectivores, namely hedgehogs (European, Amur and other species). The majority (60-75 %) of viral pathogens enter the human population from animals, of which at least 70% are wild. The influence of the exploitation of wild animals by mankind on the appearance of pandemics has been observed, which in itself provokes the emergence of new viruses in nature. Flora and fauna, adapting to the growing anthropogenic impact, are geographically redistributed.

The microflora of the oral cavity of domestic ruminants, presented by transitive gram-negative species of bacteria (cocci and sticks) in cows, transient and obligate gram-positive (usually cocci) bacteria in sheep was studied. The lowest contamination of the sheep mouth mucosa was observed in autumn, and the largest in summer. Seasonal features of bactericidal activity of saliva and its main components (lysozyme, properdin and complement system) are shown. Differences of the above indicators in cows and sheep are considered. Low activity is typical for saliva complement system in ruminants in general and sheep in particular. Lysozyme activity and properdin content are maximum in cows and sheep in summer, with elongation towards autumn (exception – lysozyme activity in sheep extends in spring).

The authors assessed the possibility of substitution of the serum component with tissue extracts (muscles, liver, kidneys) of bovine fetuses in the culture medium during the cultivation of transplanted LEK and Vero cell lines, as well as the reproduction of infectious rhinotracheitis IR, PI-3 viruses and reovirus on them. The greatest stimulating effect on LEK and Vero cells was obtained from bovine fetuses muscle extract. The effect of this extract on the proliferative activity of LEK and Vero cells is significant and amounts to 27 and 25%, respectively. The power of the effect of liver and kidney extracts is significantly lower and equal, respectively, 15 and 18% for LEK and 14 and 19% for Vero, although it is reliable. The reproductive activity of IR and PI-3 viruses when using tissue extracts was inferior to that when using blood serum. The stimulating effect of blood serum and muscle extract on the reproduction of reovirus was comparable. The effect of fetal muscle extract on the reproduction of IR, PI-3 viruses and reovirus is reliable and amounts to 29, 31 and 33%, respectively. In general, it is close to that of the blood serum of bovine fetuses - 30, 35 and 36%. The power of the influence of the liver and kidney extracts of the bovine fetuses is significantly lower and comparable to that of the blood serum of the cows themselves: 25, 23 and 20%, although it is reliable.

The physiological functions of nitric oxide (II) are diverse, and its therapeutic uses continue to expand. Many methods have been found to regulate the production of this compound, both physiological, regulated by the body itself, and as a result of various, drug and non-drug, external influences, correcting the ability of cells, organs and tissues to produce nitric oxide (II). The drug estrophan (synthetic prostaglandin PGF2α) has an activating effect on the nitric oxide (II) system and on sex hormones that regulate the reproductive functions of cows. The introduction of estrophan to cows is accompanied by an increase in the synthesis of nitric oxide (II), estrogen in the body of cows, and a decrease in progesterone. A high level of interrelation of estrogen with nitric oxide (II) was shown, the value of the correlation coefficient is (r = 0.552; p < 0.05). Correlation of the level of nitric oxide (II) with estrogen allows making an assumption of its bioregulatory functions, including the sexual cycle. The introduction of estrophan had no effect on the biochemical parameters in the blood serum of cows.

Feeding of a cow with protected amino acids is accompanied by the increase of the estrogen and progesterone, a slight decrease in nitric oxide (II) in the blood serum. It is worth noting that the reproductive cycle, fertility, and general condition of the cows of the experimental group improved.