LAUSR

BACKGROUND The circular replication-associated protein (Rep)-encoding single-stranded (CRESS) DNA virus emergence in diverse host has been associated with severe disease. Porcine circovirus-like virus (Po-Circo-like (PCL) virus) is a CRESS DNA virus, the prevalence and pathogenicity of which are rarely studied. METHODS We obtained two blood samples, four fecal samples and two intestinal samples from a pig farm suffered from diarrheal disease in the delivery room in Sep. 2020 and attempted to isolate and identify a causative pathogen. Subsequently, only PCL virus was positive, and qRT-PCR was designed to detect the loading titer of PCL virus. We then initiated a heightened surveillance program on the pathogenicity and epidemiology of PCL virus. RESULTS Six PCL virus strains, with severe diarrhea and hemorrhagic enteritis, have been found in six different pig farms in Guangdong province, China. A multiple sequence alignment of these PCL viruses and bovine circovirus like virus/CH showed a similarity of 92.5%-94.8% for the Rep protein, indicating these PCL viruses is highly homologous to Bo-Circo-like virus associated with calf diarrhea. There were striking similarities between the PCL virus and bovine circovirus like virus outbreaks in aetiological settings and Genomic sequence. We found that 11.2% (20/178) of diarrhea samples and 13.3% (6/45) of pig farms were positive for PCL virus, suggesting that PCL virus may have spread widely in Pig farms. Morever, this article underscores the risk of PCL virus spilling over and adapting to new species. CONCLUSIONS Porcine circovirus-like virus was found to be associated with porcine diarrheal disease in China. This article is protected by copyright. All rights reserved.