Prevalence and characteristics of a novel feline parvovirus-like virus in dogs in China

Canine parvovirus (CPV) infection is one of the most dangerous infectious diseases in young puppies worldwide. In this study, 192 diarrheal fecal samples were collected from 2019.4~2021.6 for monitoring the molecular prevalence of CPV among dogs by a specific PCR targeted VP2 gene in Southwest China, and 113 samples were detected as parvovirus-positive. Surprisingly, 28/113 (24.8 %) parvovirus-positive strains were identified as feline parvovirus (FPV)-like strains based on the evolutionary analysis of the 567 bp VP2 fragments which contain the aa residue of VP2 323D typical for FPV. To gain insights into the molecular and biological characteristics of these FPV-like viruses in dogs, 6 FPV-like strains were successfully isolated and genome sequenced. Analysis of genomic sequences suggested that the 6 isolates can represent a novel parvovirus in dogs, named FPV-like-1, which have the following characteristics: a. The genomic nucleotide (nt) and individual proteins are most genetically related with FPV instead of CPV. b. The VP2 proteins contain all unique amino acid (aa) residues typical for FPV. c. Compared with the FPV, the VP1 intron and NS1 exhibit some identical unique mutations. These FPV-like-1 strains could hemagglutinate swine erythrocyte at a broad range of PH values between 6.0 and 8.0 and replicate efficiently in MDCK cell line. Moreover, these isolates caused canine systemic infection via oral administration. Analysis of VP2 sequences of CPV available in GenBank revealed that the FPV-like strains had already existed in five countries of China, Vietnam, Pakistan, Thailand, Australia, and have circulated widely among dogs in China.