First detection and genomic analysis of canine circovirus in a dog with hemorrhagic diarrhea in South Korea: a case report

This report presents the first detection of canine circovirus (CanineCV) in South Korea, which was identified in a dog with hemorrhagic diarrhea. A 5-year-old male Golden Retriever presented with acute, watery and bloody diarrhea that had persisted for three weeks. Pathologically, granulomatous inflammation, fibrinoid vasculitis, and hemorrhagic foci were observed in the small intestine and mesenteric lymph nodes. Characteristic intracytoplasmic amphophilic inclusion bodies were observed in histiocytic cells within the granulomatous lesions. CanineCV was amplified by polymerase chain reaction from the small intestine, mesenteric lymph nodes, and fecal samples. A genomic analysis of the complete capsid gene from the Korean strain of CanineCV revealed that it shares the highest nucleotide and amino acid sequence similarities, at 94.2% and 94.1% respectively, with the American UCD3-478 isolate. Phylogenetic analysis based on the nucleotide sequence of the capsid gene classified the Korean strain as type 4 CanineCV. This case highlights the importance of genomic surveillance for emerging pathogens in South Korea and lays the groundwork for further research into the epidemiology and pathogenicity of CanineCV in canine enteric diseases.