Phylogenetic analysis of cat coronaviruses and SARS-CoV-2 in Surabaya

Abstract

Background and Aim: Questions about the origin of coronavirus and its introduction to human beings have persisted. The detection of a variety of coronavirus related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in bats and pangolins led to the widespread belief that SARS-CoV-2 originated from wild animals and was introduced to humans through an intermediate animal. Thus, coronaviruses from animals, especially those in close contact with humans, have attracted particular attention. This study aimed to phylogenetically analyze feline enteric coronavirus (FECV), feline infectious peritonitis virus (FIPV), and SARS-CoV-2 found in cats in Surabaya amid the COVID-19 pandemic. The results will provide a basis for developing basic preventive and pet healthcare strategies. Materials and Methods: Samples were collected on physical examinations of domestic and Persian cats (males and females) from March 2020 to March 2022. Samples were collected if there were clinical signs of FECV and FIP based on a veterinarian's diagnosis in several clinics in Surabaya. Laboratory examinations in this study were performed by reverse-transcription-polymerase chain reaction (RT-PCR) with primers for conserved regions of FIP and FECV, DNA sequencing was performed with Applied Biosystem Genetic Analyzer protocol, homology analysis was performed using Basic Local Alignment Search Tool NCBI, phylogenetic analysis was carried out with BioEdit 7.2 software, and sequences were compared with references from GenBank. Results: Samples were collected from ten cats showing clinical signs of FECV and FIP, based on a veterinarian's diagnosis. On RT-PCR examinations performed with specifically designed primers for detecting FIPV in blood, peritoneal fluid, and feces, only one sample showed positivity for FIPV (1/10), namely, a peritoneal sample from a domestic cat in Surabaya. Homology analysis of the FIPV Surabaya isolate showed 98% similarity with FECV and FIPV reported in GenBank (MT444152 and DQ010921, respectively). In phylogenetic analysis, the FIPV Surabaya isolate was clustered together with SARS-CoV-2 of Clade A (MT198653) from Spain, SARS-CoV-2 Clade A (MT192765) from the USA, SARS-CoV-2 Clade D (039888) from the USA, and SARS-CoV-2 Clade F (MT020781) from Finland. Conclusion: This study revealed a relationship between the SARS-CoV-2 viruses that infect humans and cats (FECV), which is an important finding for those keeping cats at home. However, this finding requires further comprehensive support from laboratory studies.