Hepatitis due to equine abortion virus. Comparison between the liver histology in human, canine, duckling, and equine viral hepatitis.

Five livers of equine fetuses, aborted due to the action of equine abortion virus, five livers from men, two of whom died of epidemic hepatitis and three obtained by needle biopsies, 5 livers of dogs with infectious canine hepatitis and 7 livers of ducklings that had hepatitis, were studied histopathologically. The foals' livers were studied by several staining methods and the others by H. E. only. The results indicate that the lesions are quite similar in the four species with the appearance of nuclear inclusion bodies only in foals and dogs. The strong staining properties of the nuclear inclusion bodies in infectious canine hepatitis and the weak staining properties of the equine virus abortion reveal that the protein-DNA association is different resulting in a different electropolarity. The lesions in foals are of two main types, one a Necrotic-Mosaic Type in which the hepatocyte degeneration is irregularly distributed within the hepatic lobules and the other an Hyperplastic Type in which marked regeneration occurs. In the Hyperplastic Type the practical absence of plasmocytes in foals' livers might suggest that if the newborn is a female, abortions may occur later in life because the virus remained alive in colts which were born in an immune tolerance state.Histologically the picture in the livers of aborted foals assume features of a viral hepatitis similar to the viral hepatitis in men, dogs and ducklings.