Isolation, identification, and genetic evolution analysis of the VP2 gene of feline calicivirus strain ZZ202306

This study examined a suspected instance of feline calicivirus (FCV) infection at a veterinary hospital in Zhengzhou, Henan Province, People's Republic of China. Reverse transcription-polymerase chain reaction (RT-PCR) confirmed the presence of FCV, and subsequent cultivation in Crandell-Rees feline kidney (CRFK) cells resulted in the identification of the virus as the FCV strain ZZ202306. Characterization via immunofluorescence assay and Western blotting demonstrated specific interaction with a monoclonal antibody directed against the FCV VP1 protein. Electron microscopy revealed viral particles with a diameter of approximately 40 nanometers, consistent with the morphological characteristics of FCV. Biological assays indicated a viral titer of 107.96 50% tissue culture infectious dose (TCID50) per 0.1 milliliter, with peak replication occurring between 6 and 18 hours post-inoculation. Sequencing and phylogenetic analysis of the VP1 gene showed high genetic similarity between the isolated strain and various domestic and international FCV strains, positioning it within the same evolutionary clade but distinct from other caliciviruses.