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Pathology of hepatitis A infection in the owl monkey (Aotus trivirgatus)
Abstract:
Sequential liver biopsies of owl monkeys that had been experimentally infected with one of two strains of hepatitis A virus (HM-175 or PA-33) were examined for histopathologic alterations. Preinoculation biopsies were normal with only occasional minimal mononuclear cell infiltrates in portal tracts and hepatic lobular parenchyma. Histopathologic features that were present in biopsies taken during the period of elevated serum alanine aminotransferase activity (16-43 days after the intravenous inoculation of virus) included infiltration of predominantly mononuclear inflammatory cells into portal tracts and surrounding parenchyma, degeneration and necrosis of hepatocytes, and hypertrophy of Kupffer cells. Changes were similar in monkeys infected with either HM-175 or PA-33 virus strains. Convalescent biopsies (147-186 days after inoculation) showed resolving lesions with mild portal inflammation and occasional focal collections of inflammatory cells in the parenchyma. These histologic changes are similar to those associated with hepatitis A infection in man, chimpanzees, and several species of marmosets, and support the further use of the owl monkey as a model of human hepatitis A.
Insights
Owl monkeys experimentally infected with hepatitis A virus showed liver damage similar to human hepatitis A. These findings support the owl monkey as a valuable model for studying hepatitis A virus.
Area of Science:
- Hepatology
- Virology
- Primate Models
Background:
- Hepatitis A virus (HAV) infection causes liver inflammation.
- Animal models are crucial for understanding HAV pathogenesis and developing treatments.
- Owl monkeys have been used to study viral hepatitis.
Purpose of the Study:
- To histopathologically examine liver alterations in owl monkeys experimentally infected with two strains of hepatitis A virus (HM-175 and PA-33).
- To evaluate the suitability of the owl monkey as a model for human hepatitis A.
Main Methods:
- Sequential liver biopsies were performed on owl monkeys before inoculation, during peak alanine aminotransferase activity (16-43 days post-inoculation), and during convalescence (147-186 days post-inoculation).
- Histopathologic examination focused on inflammatory cell infiltration, hepatocyte degeneration/necrosis, and Kupffer cell activity.
- Two HAV strains, HM-175 and PA-33, were used for experimental infection.
Main Results:
- Pre-inoculation biopsies showed normal liver histology.
- During elevated liver enzyme activity, biopsies revealed mononuclear inflammatory cell infiltration, hepatocyte damage, and Kupffer cell hypertrophy.
- Histologic changes were comparable between monkeys infected with HM-175 and PA-33 strains.
- Convalescent biopsies demonstrated resolving lesions with residual inflammation.
Conclusions:
- The observed histopathologic changes in owl monkeys mirror those seen in human hepatitis A.
- The study supports the owl monkey as a relevant and valuable animal model for hepatitis A research.
- Further studies using this model can advance understanding of HAV infection and disease.