Researchers from Japan suggest that the tree shrew may be a practical small-animal model for studying the progression of human hepatitis C virus (HCV) infection. This discovery would replace the need for rare and expensive studies using chimpanzees, currently the only validated animal model for HCV. They report their findings in the January 2010 issue of theJournal of Virology.
HCV is a highly potent viral infection that can ultimately lead to chronic hepatitis, liver steatosis, cirrhosis, and hepatocellular carcinoma. The current course of treatment against HCV includes interferon therapy (stimulating the processes within cells that slow the reproduction and growth of the virus) in conjunction with the antiviral drug ribavirin, however, the combination treatment is difficult for patients to endure and is often ineffective.
The tupaia (Tupaia belangeri), also known as a tree shrew, is a small non-primate mammal commonly found in certain regions of Southeast Asia. Previous studies have shown tupaias to be susceptible to a wide range of human-pathogenic viruses, including hepatitis B. In this study researchers inoculated tupaias with HCV and analyzed the progress of infection over a three-year period. Results showed mild hepatitis and intermittent viremia during the acute phase of infection, chronic hepatitis that worsened over time, and the detection of liver steatosis, cirrhotic nodules and the production of new tumors.
"These data suggest that the tupaia is a practical animal model for experimental studies of HCV infection," say the researchers. "Comparative studies of HCV infection in different species will help us to understand the basic mechanisms of persistent infection."
(Y. Amako, K. Tsukiyama-Kohara, A. Katsume, Y. Hirata, S. Sekiguchi, Y. Tobita, Y. Hayashi, T. Hishima, N. Funata, H. Yonekawa, M. Kohara. 2010. Pathogenesis of hepatitis C virus infection in Tupaia belangeri. Journal of Virology, 84. 1: 303-311.)