Epithelial changes in porcine exudative epidermitis. An ultrastructural study.

The normal fine structure of the epidermis in piglets is similar to that in other mammals. Ten cases of exudative epidermitis were studied in different stages. In acute cases a crust of parakcratotic cells was evident. The cells of the stratum intermedium and the outer layers of the stratum spinosum were swollen and vacuolated. Desmosomes and tonofibrils were reduced in size and number. The intercellular spaces were enlarged and contained an opaque material. In subacute and mild cases the lesions were less pronounced. The healing process was studied in one less severe, acute case. The observations arc interpreted as indicating a primary lesion in the Stratum granulosum and possibly in adjacent cells of the stratum spinosum. No evidence of a bacterial etiology was found. The observed changes are similar to those seen in viral disease of the skin.