Molecular epidemiology and phylogenetic analysis of feline calicivirus in Kunshan, China

Abstract

Feline calicivirus (FCV) is a highly contagious virus in cats, which typically causes respiratory tract and oral infections. Despite vaccination against FCV being a regular practice in China, new FCV cases still occur. Antigenic diversity of FCV hinders the effective control by vaccination. This is first report which aims to investigate the molecular epidemiology and molecular characteristics of FCV in Kunshan, China. The nasopharyngeal swabs were collected from cats showing variable clinical signs from different animal clinics in Kunshan from 2022 to 2023. Preliminary detection and sequencing of the FCV capsid gene were performed to study genetic diversity and evolutionary characteristics. FCV-RNA was identified in 52 (26%) of the samples using RT-PCR. A significant association was found between FCV-positive detection rate, age, gender, vaccination status and living environment, while a non-significant association was found with breed of cats. Nucleotide analysis revealed two genotypes, GI and GII. GII predominated in Kunshan, with diverse strains and amino acid variations potentially affecting vaccination efficacy and FCV detection. Notably, analysis pinpointed certain strains’ association with FCV-virulent systemic disease pathotypes. This investigation sheds light on FCV dynamics, which may aid in developing better prevention strategies and future vaccine designs against circulating FCV genotypes.

First report of molecular epidemiology and phylogenetic characteristics of feline herpesvirus (FHV-1) from naturally infected cats in Kunshan, China

“…Viral respiratory diseases are a serious health issue of cats worldwide [ 25 , 42 , 43 ]. Feline herpesvirus-1 (FHV-1), feline calicivirus (FCV), Mycoplasma felis , Chlamydia felis and Bordetella bronchiseptica are considered main etiological agents of feline upper respiratory tract infections [ 3 , 5 , 24 , 25 , 44 ]. FHV-1 is considered a main etiological agent for respiratory infections in cats and according to an estimate about 50–70% of cases of respiratory infections are associated with FHV-1 [ 45 ].…”

“…Younger animals are more susceptible to FHV-1 infection. A core vaccine including FHV-1, feline calicivirus (FCV), and feline panleukopenia virus (FPV) is commercially available and administered worldwide [ 4 , 5 ]. Vaccines usually provide good protection against FHV-1 infections; however, vaccines cannot prevent the development of carrier state and infection in cats [ 3 , 6 , 7 ].…”