This article presents the results of studies on biological samples collected from 640 swabs taken from dogs and cats across various regions of the Republic of Kazakhstan. These samples were part of a monitoring study on the spread of coronavirus among domestic animals. Total RNAs were isolated using the magnetic sorption method with the ALPREP kit and subsequently analysed with the ALSENSE-SARS-CoV-2 RT-qPCR kit. Real-time RT-PCR analysis revealed that 104 samples tested positive within 22–37 amplification cycles. These positive samples were then cultured in Vero cell lines to confirm the presence of the virus. The biological activity of the resulting virus-containing suspension was determined using the Reed-Muench method. During cultivation, one viral isolate with a biological activity of 5.83±0.08 lg TCID50/ml was obtained. A microphotograph of the virus was taken using an electron microscope to determine its size, shape, and structure, which confirmed its morphology corresponding to the Coronaviridae family. The data obtained further indicate that domestic animals can suffer from and carry coronavirus. It is becoming increasingly evident that the virus can infect and replicate in the organs of various farm and domestic animals.

Two recombinant influenza A virus vectors expressing the ESAT 6 and TB10.4 mycobacterial proteins from the non-structural (NS) gene were constructed via reverse genetics technique to develop a specific means of prophylaxis for bovine tuberculosis. We experimented to determine optimal conditions for growing recombinant vectors in Vero cell culture and chick embryos. This study established that the maximum amount of virus builds up in a Vero cell culture with the Dulbecco’s Modified Eagle’s Medium (DMEM) serum-free medium. However, using cell culture to produce vector vaccines is labour-intensive and inefficient. An alternative way, a traditional, time-tested technique, is provided by growing samples in chick embryos. One of the advantages of this technique is its affordability and availability, enabling easy scale-up of vaccine production. In the optimization experiments, the FLU-ΔNS_ESAT 6 and FLU-ΔNS_ТВ10.4 viruses constructed were inoculated into 10-day-old chick embryos. It was determined that the optimal incubation temperature that led to the highest virus build-up was 37 ± 0.5 °С. And the infectious activity level of the FLU-ΔNS_ESAT 6 recombinant vector was at 8.95 ± 0.07 log10EID50 0.2 cmE−3, while that of the FLU-ΔNS_ТВ10.4 was at 9.20 ± 0.07 log10EID50 0.2 cmE−3, what was provided by infectious doses of 1000–10000 EID50 , which makes it possible to create a virus-containing material with a hemagglutination activity level of 1:64. The size of recombinant vector amplicons expressing proteins ТВ10.4 and ESAT 6 was 1170 bp and 1175 bp, respectively. Electron microscopy images confirm that the developed virions are morphologically similar to the avian influenza virus.