Abstract
In 1998, histopathological examinations of 6 weaned, stunted pigs on 2 farms in Mie Prefecture revealed depletion of lymphocytes in the lymphoid follicles and grape-shaped basophilic intracytoplasmic inclusion bodies in the mononuclear cells of the lymphoid organs. Electron microscopy revealed a large number of virus particles (about 17.5nm in diameter) arranged in rope-like structures in the intracytoplasmic inclusion bodies. Immunohistochemical staining with a convalescent serum of pigs recovered from post-weaning multisystemic wasting syndrome (PMWS) and in situ hybridization with a DNA probe based on the nucleotide sequence of porcine circovirus type 2 (PCV-2) showed the virus to be PCV-2. Characteristic PCV-2 DNA was detecteed by PCR. Clinical and pathological findings of pigs in this study were similar to those obtained from cases of PMWS in Canada, the United States, and Europe, although, in this instance, pathogenic organisms other than PCV-2 also were detected.
