Porcine postweaning multisystemic wasting syndrome in Korean pig: detection of porcine circovirus 2 infection by immunohistochemistry and polymerase chain reaction

This report describes the first diagnosis of porcine circovirus (PCV) infec tion in weaned pigs with postweaning multisystemic wasting syndrome in Kore a by immunohistochemistry and polymerase chain reaction. The most unique le sions were multifocal granulomatous inflammation affecting lymph nodes, liv er, and spleen, characterized by infiltrates of epithelioid macrophages and multinucleated giant cells. Circoviral antigen was detected in formalin-fi xed sections and was usually present in large, round, dendritic cells in th e white pulp of spleen and remnants of follicles in lymph nodes. Lymphoid f ollicles in the tonsils also contained PCV antigen. A 530-bp DNA fragment o f circovirus was successfully amplified from all tested lymph nodes, liver, and spleen.