Detection and molecular characterization of novel porcine bufaviruses in Guangxi province

Bufavirus (BuV) can infect a variety of hosts, including human, bats, rats, dog, swine and shrew species and are suggested related to diarrhea disease. Porcine bufaviruses (PoBuV) were first detected in Hungarian pig farms in 2016. To determine the prevalence and genetic diversity of PoBuV in China, we developed SYBR Green-based real-time PCR assays to detect PoBuV in Guangxi pigs. Real-time PCR detected PoBuV in 30 (29.13%, 30/103) of the samples with diarrhoeal intestinal tissues and rectal swabs. PoBuV-positive intestinal tissues and rectal swabs samples, co-infection with PEDV (15/30, 50.0%), followed by PDCoV (8/30, 26.67%), PoRV (6/30, 20.0%), PRRSV (5/30, 16.67%), and PCV2 (3/30, 10.0%) were observed. Fourteen complete genomes were cloned and sequenced. The results showed that they were 4189 bp in length and combined three open reading frames (ORFs) in the order 5'-NS1-VP1/VP2-3'. Fourteen strains shared 96.5%-99.8% identity among themselves and 92.7%-97.9% with the PoBuV reference sequences. Phylogenetic analysis based on the deduced amino acid sequence of the VP2 gene showed fourteen strains belonging to PoBuV and were grouped into the three branches. These results help to provide new insight into the molecular epidemiology of PoBuV in the world.