V. V. Kosheliev

The article highlights the results of an analysis of literary sources, emphasizing the importance of studying naturally occurring infections, particularly dangerous ones, caused by pathogens belonging to the Flaviviridae family, in relation to human health and veterinary medicine. This family is divided into four genera: Flavivirus, Pestivirus, Hepacivirus, and Pegivirus. The Flavivirus genus (Orthoflavivirus), the most significant for humans, belongs to the arbovirus family, which is transmitted by arthropod vectors, such as mosquitoes and ticks. Vectors become infected when they feed on the blood of infected reservoir animals. Afterward, they are capable of transmitting the virus to humans. Transmission of pathogens through unprocessed milk and organ transplantation is also possible. The viruses of yellow fever, Japanese encephalitis, tick-borne encephalitis, Omsk hemorrhagic fever, dengue, Zika, West Nile, Murray Valley encephalitis, and Pyasanu encephalitis, as well as Kiasanur forest disease and Alhumra hemorrhagic fever, are of epidemiological significance

The World Organization for Animal Health (WOAH) has classified enzootic bovine leukemia (EBL) as a disease that significantly affects international trade. The zoonotic potential of BLV is an open question for science today. In Ukraine, for this purpose, RID is mainly used. One of the main problems in the field of cell cultures is mycoplasma infection. The aim of the research was to study the influence of mycoplasma contamination on the antigen-producing ability of FLK-BLV cell cultures. PCR method was used to indicate mycoplasma contamination of FLK-BLV cell cultures. For decontamination, the antibiotic tiamulin was used at a concentration of 30μg/mL in the culture medium, the treatment duration was 21 days. Contamination of FLK-BLV cell cultures with mycoplasma contributed to the inhibition of cell proliferation and a decrease in monolayer formation by 30% for contaminated cultures and by 20% for decontaminated cultures. Decontamination from mycoplasma improves the growth properties of FLK-BLV cell cultures. Mitotic activity with mycoplasma contamination decreased on average by 34.5% compared to primary pure cultures. After decontamination with the antibiotic tiamulin, the mitotic activity of cell cultures increased by 17.25% compared to the contaminated culture, but at the same time was lower by 24.25% compared to primary pure cultures. Analysis of the antigen-producing biological activity of sublines of cells contaminated with mycoplasma, decontaminated from mycoplasma and primary pure cultures indicates an increase in antigen-producing properties and antigen titer due to decontamination of cell cultures. The absence of a working antigen titer (at ++++) from the contaminated FLK-BLV-U subline was established in comparison with the working antigen titer of the titer in the native antigen solution from the decontaminated FLK-BLV-U culture and titers from 1:0.5 to 1:1 from the initially pure uncontaminated cell cultures FLK-BLV-P 1, FLK-BLV-P 2.