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

The research compared the impact of the equine abortion virus on the liver histology among various species, namely humans, dogs, ducklings, and horses. It assessed the characteristics of the liver lesions caused by this virus in the different species and explored how the virus may lead to differences in the liver cells’ biochemical properties.

Method of Investigating the Effects of the Equine Abortion Virus

• The study included liver specimens from various sources; five from equine fetuses aborted due to the equine abortion virus, five from humans (two of whom died from epidemic hepatitis and three obtained through needle biopsies), five from dogs with infectious canine hepatitis, and seven from ducklings with hepatitis.
• These specimens were studied using histopathology, which is the microscopic examination of tissues for signs of disease.
• Different staining methods were used on the foal livers, while the human, duckling, and dog livers were only treated with Hematoxylin and Eosin stains.

Findings of the Equine Abortion Virus Study

• The histopathological results showed that the liver lesions caused by the virus were fairly similar across the four species.
• However, nuclear inclusion bodies, clusters of viruses observed in host cells, were only found in the foals and dogs.
• Differences were observed in the staining properties of these inclusion bodies in dogs and equines, suggesting that the protein-DNA relationship varies, possibly leading to a change in electropolarity, the inherent charge distribution in the cells.
• It was noted that the lesions in foal livers tended to fall into two categories, Necrotic-Mosaic Type, where liver cell decay is irregularly distributed, and Hyperplastic Type, where significant regeneration occurs.
• The absence of certain white blood cells, called plasmocytes, in the foals’ livers in case of Hyperplastic Type might suggest that if the newborn is a female, abortions may occur later in life because the virus remains alive in foals born in a state of immune tolerance.
• The study concluded that the liver damage in aborted foals due to the equine virus bears similarity to the viral hepatitis in humans, dogs, and ducklings.