Studies on the pathogenicity and carcinogenicity of duck hepatitis B virus-Relationship between duck hepatitis B virus in sera and pathological changes in livers of ducks

114 2-year older ducks from Qidong county in the high incidence area of duck hepatoma and 98 1.5-year older ducks from Gaoyou county in the low incidence area of duck hepatoma were studied for inquiring into the relationship between duck hepatitis B virus(DHBV)and liver discase or hepatoma. Duck hepatitis B virus in sera was respectively detected by dot-blot hybridization and duck liver spccimens were examined histopathologically. The characteristics of duck liver disease was determined. DHBV-positive rate between the two regions, the characteristics of liver diseases between DHBV-positive ducks and DHBV-positive ducks and DHBV-negative ducks were compared and were made analysis with Ridit non-parametric method. The results showed that there was no significant significant difference of the characteristics of liver disease and the morbidity of hepatoma between DHBV-positive and DHBV-negative ducks in Qidong county and in Gaoyou county under the same raising conditions. Compared DHBV-positive ducks in Gaoyou county with DHBV-positive ducks in Qidong county, there was significant difference of pathological changes such as bile duct proliteration, cell degeneration, amyloidosis and....