Prevalence and molecular characterization of parvovirus in domestic kittens from Northeast China during 2016-2017

Feline panleukopenia virus (FPV) and Canine parvovirus (CPV) are significant enteric viruses in cats, causing acute diarrhoea, hemorrhagic enteritis and leukopenia. To better understand the prevalence and molecular epidemiology of parvovirus in domestic kittens in China, we tested for these viruses in 143 faecal samples collected from diarrhoea-affected/healthy domestic kittens during 2016-2017 and analysed the sequences of parvovirus-positive samples. According to the results, 55 samples (38.46%) were positive for parvovirus; among these, 1 (named as CC-04/16-05) was identified as a new CPV-2a strain, 1 (LY-02/16) as a new CPV-2b strain and 53 as FPV. These findings show CPV-2a/2b and FPV to be circulating in domestic kittens in Northeast China. Genetic analysis shown that all of the FPV strains isolated in China can be grouped into the FPV G1 cluster, whereas two FPV vaccine strains are classified into the G2 cluster, revealing that this may be an important reason for the limited effectiveness of vaccines against FPV. Furthermore, a common mutation (Tyr324I1e) was present in strains CC-04/16-05 and LY-02/16, and Phe267Tyr and Thr440Ala mutations were present only in strain LY-02/16. The emergence of novel CPV-2a/2b strains with critical mutations, which related to the host ranges of CPV, suggesting that there are a potential risk of the outbreak of CPV in felid.