Electron microscopy on mucosal and cutaneous lesions in contagious papular dermatitis of Japanese Serow (Capricornis crispus).

Abstract

An electron microscopic study was performed on mucosal and cutaneous lesions of eight Japanese serows infected with contagious papular dermatitis virus. A slight infiltration of lymphocytes and histiocytes, but no virion were seen in the germinal layer and the lower prickle-cell-layer. The cytoplasm was edematous around the nucleus in the cells of the middle prickle-cell-layer. There were many mature viral particles and viroplasm which consisted of electron opaque granular matrix and immature particles in the cytoplasm. The mature particles were oval to cylindrical in shape and measured 300 by 160 nm in size. Tubular structures and filamentous materials were observed in the nuclei of the infected cells. Perinuclear edema spread over in the whole cytoplasm and cytoplasmic organelles were obscure in the cells of the upper prickle-cell-layer. There were numerous mature particles in the cytoplasm, and occasionally such structures as long band-like or spherical accumulations of microgranules were accompanied. It was concluded that papular lesions were caused by viral replication in the cells of the prickle-cells-layer.