猪圆环病毒2型和3型毒株的分离鉴定及致病性研究OA

To isolate and identify Porcine circovirus 2(PCV2)and Porcine circovirus 3(PCV3)and to assess their pathogenicity,we inoculated PCV2d and PCV3b-positive pig tissue samples from our laboratory onto PK15 cells and primary porcine kidney epithelial cells for viral isolation..Two virus strains were obtained and designated as PCV2JL11 and PCV3JL3.The PCV2JL11 strain exhibited a virus titer of 106 TCID50/mL and the viral load of the PCV3JL3 strain was measured at 4.638 lg(copies/μL).Subsequent pathogenicity tests were conducted in both mice and pigs.Quantitative PCR analysis confirmed the presence of PCV2 and PCV3 in various organs of both animal models.In animal experiments,pigs infected with the PCV2 strain exhibited an average daily weight gain of 0.366 kg,which was significantly lower than that of the PBS control group(P<0.05).In contrast,pigs infected with the PCV3 strain showed an average daily weight gain of 0.364 kg,which was not significantly different from the PBS group(P>0.05).Histopathological examination using hematoxylin and eosin staining revealed that the PCV2/PCV3 infection groups had thickness of lung alveolar walls,reduction of inflammatory cells,decrease of lymphocytes in the lymph nodes,and loose tissue arrangement with indistinct boundaries.Overall,these findings demonstrated that the isolated PCV2JL11 and PCV3JL3 strains were pathogenic to weaned piglets,thereby establishing a foundation for further investigations into the pathogenic mechanisms of PCV2 and PCV3.