RESUMO
Porcine circovirus 2 (PCV2) is the cause of postweaning multisystemic wasting syndrome (PMWS). The most common lesions of PMWS are lymphohistiocytic to granulomatous lymphadenitis, interstitial pneumonia and interstitial nephritis, with intracytoplasmic amphophilic botryoid inclusion bodies in macrophages. In addition to these typical changes, intracytoplasmic botryoid inclusion bodies were observed in bronchial, bronchial glandular, and renal tubular epithelium of several pigs from 4 different farms in Western and Eastern Canada. PCV2 inclusion bodies were demonstrated to be located in the cytoplasm of epithelial cells by immunohistochemical staining for PCV2 and cytokeratin antigens and by ultrastructural demonstration of viral particles in the inclusion bodies within renal tubular epithelium.