Abstract: 53 experimental tree shrews, the lowest primates, were inoculated with 0.5 ml human serum containing HBV through the femoral vein and abdomenal cavity successively into cach animal. Four tree shrews were injected with bovine serum by the same way and five were used as controls without any treatment.Before inoculation all of 62 animals were found negative for HBsAg and anti-HBs in their sera. After inoculation blood samples were drawn through femoral vein from one to 35 weeks and examined for HBV markers by passive hemagglutination assay （PHA）,hybridization spot test and electron microscopy.The biopsied liver sections were examined for the intrahepatocytic HBsAg and HBcAg by using immunoperoxidasc technic.In result, 45 of 53 were positive for HBsAg, anti-HBs or both by PHA, 30 of 53 were positive for HBV DNA by molecular hybridization test. In the sera samples of three animals examined under the electron microscopy, 22-nm spherical and tubular form of HBsAg particles and a small amount of 42-nm Dane particles were observed.In nine cases of liver biopsied from sera-HBsAg positive animals, eight were found positive for HBsAg in cytoplasm and two for HBcAg in nucleus of liver cells. Spotty necrosis of liver cells and portal inflammation were found in some cases among the infected animals. No positive results were obtained in any of the nine controls.These results suggest that tree shrew is susceptible for human HBV inoculation, the incidence of experimental infection may rise to 84.9%,so it may be used as an experimental animal model for studying human HBV infection and its correlation with liver cell carcinogenesis.

Key words: Human HBV infection, HBsAg, carcinogenesis