Two novel sites determine genetic relationships between CPV-2 and FPV: an epidemiological survey of canine and feline parvoviruses in Changchun, China (2020)

Canine parvovirus (CPV-2) and feline parvovirus (FPV) cause severe hemorrhagic diarrhea disease in dogs, cats, and fur-bearing and wildlife carnivores worldwide, continuing to pose significant threats. In this study, 140 rectal swabs were collected from 70 domestic dogs and 70 cats with clinical diarrhea in veterinary clinics in Changchun during 2020. A total of 64.3% (45/70) of dogs and 55.7% (39/70) of cats tested positive for CPV-2 or FPV using colloidal gold strips. Amino acid (aa) sequence alignment of the VP2 protein from 39 CPV-2 and 36 FPV samples revealed that 79.5% (31/39) were CPV-2c, 17.9% (7/39) were a new CPV-2a, and 2.6% (1/39) were mink enteritis virus (MEV). and 8.3% (3/36) FPV from the cats was infected by CPV-2, which suggested that CPV-2c was the dominant variant in dogs and FPV was the major pathogen in cats in Changchun city. Phylogenetic relationships of VP2 genes showed that 26 parvoviruses were closely related to domestic strains previously published in China; however, 8 FPVs and CPV-JL-15/China/2020 were clustered in the lineage of South Asiatic and European countries, and 7 out of 8 FPVs were close to Italy. In addition to Q247H, I248Y, F544Y, and E/V545V/K, two novel site mutations of N23D or L630P in NS1 protein, associated with viral cross-species transmissions, were first found as a reminder of genetic relationships of CPV-2 variants and FPVs in the same branch. Thus, regular and massive virus surveillance of parvovirus is necessary to cope with its ongoing infection, circulation, mutations, and evolutions to new subtypes with strong survival abilities.