The study of the course of the infectious process in lungs of cats during experimental infection with SARS-CoV-2

Aim. To study and characterise the features of the course of coronavirus infection in a domestic cat model, as well as to assess the danger of SAR-SCoV-2 isolated in Russia for these animals based on the data obtained, with the possibility of extrapolating to wild felines. Material and Methods. For the study, model animals - Felis silvestris catus - were divided into 3 groups. The viral strain of SARS-Cov-2/human/RUS/Nsk-FRCFTM-1/2020 was cultivated on Vero E6 cell culture and then administered intranasally in a volume of 200 mu l, 10(5)TCID(50)/ml, to animals from the first and second groups. Model animals from the first group were euthanized and lung fragments were taken on 6-day post infection (d.p.i.), animals from the second group - on 14 d.p.i. The third group - the control group, was injected with saline in an equivalent volume. Histological sections colored with hematoxylin and eosin were investigated for pathomorphological changes in lung tissue using light microscopy. Results. According to the obtained results the pathomorphological picture in the lungs of experimental animals indicates the course of interstitial pneumonia for both 6 and 14 d.p.i. In addition, it has been determined that by 14 d.p.i. the growth of fibrous tissue in the lungs begins to be visualised, indicating the beginning of light regenerative processes. Conclusion. The study showed that cats are susceptible to the SARS-CoV-2 virus, and these model animals are characterized by the emergence of clinical manifestations and morphological patterns in the lungs, which correspond to interstitial pneumonia.