DETECTION OF A NOVEL STRAIN OF PORCINE CIRCOVIRUS IN PIGS WITH POSTWEANING MULTISYSTEMIC WASTING SYNDROME

Swine infectious agents, especially viruses, are potential public heal th risks associated with the use of pig organs for xenotransplantation in humans,Therefore, there is a need for better characterization of s wine viruses and for the development of diagnostic tests for their det ection. We report here isolation of a novel strain of porcine circovir us (PCV) from pigs with postweaning multisystemic wasting syndrome (PM WS:). Affected pigs exhibited severe interstitial pneumonia and lympho id depletion. The complete nucleotide sequence (1,768 nucleotides) of the genome of the PCV isolate was determined and compared with the seq uence of the PCV strain isolated from PK-15 cells. Sequence comparison revealed significant differences between the two PCV strains, with an overall DNA homology of 76%. Two major open reading frames (ORFs) wer e identified. ORF1 was more conserved between the two strains, with 83 % nucleotide homology and 86% amino acid homology, ORF2 was more varia ble, with nucleotide homology of 67% and amino acid homology of 65%. P CR and in situ hybridization demonstrated abundant viral DNA in variou s organs of pigs with PMWS. In situ hybridization demonstrated that th is strain of PCV targets multiple organs and infects macrophages, lymp hocytes, endothelial cells, and epithelial cells.