Experimental infection of human hepatitis B virus in tree shrews and its relation to hepatocarcinogenesis

Tree shrews were inoculated with human hepatitis B virus (HBV). More than half of the experimental animals were infected. Successive generative infection with the sera of HBV--infected tree shrews had been conducted and was prevented by hepatitis B vaccine. Experimental infection with standard HBV serum revealed that tree shrews are sensitive to HBV infection. By using this animal model, hepatocarcinogenic action of HBV and/or aflatoxin B_(1)(AFB_(10125)was investigated. The incidence of hepatocellular carcinoma (HCC) and precancerous lesion was significantly higher in the animals both infected with HBV and exposed to AFB_(1)than those either HBV--infected or AFB_(1)--ingested alone. the integration of HBV DNA into the host hepatocyte gene was found during hepatocarcinogenesis among the tree shrews infected by HBV. These results suggest that exposure to HBV and AFB_(1)may play a synergistic role in occurrence of HCC, and support the viewpoint of etiological relationship between HBV and HCC.