INFLAMMATION OF THE LIVER CAUSES MUTATIONS IN DUCK HEPATITIS-B VIRUS GENOME

To investigate whether hepatitis causes mutation in the viral genome, DNA sequences in the pre-core region of duck hepatitis B virus (DHBV) DNA were analyzed in both ducks with hepatitis and without hepatitis. Five DHBV carrier ducks were injected with DHBV particle proteins puri fied from duck serum with Freund's complete adjuvant (FCA) intrahepati cally from 14 day posthatch for 9 weeks (immunized group). Serum was d rawn at the end of the 1st and 4th week after the 1st injection of DHB V particle protein and ducks were killed at the end of the 9th week to obtain the liver. Another five ducks without treatment were used as c ontrols. All ducks of the immunized group showed moderate to severe he patitis at the 9th week. All ducks in the immunized group showed one m utation except one duck that showed two mutations only at the 9th week . Mutations were observed in the 5th, 13th, 21st, 22nd, and 28th codon of the pre-core region. All of them were point mutation at the 3rd ba se in the triplets. The frequency of mutation was different in each du ck from 20% to 60% but not 100%. There was no mutations in ducks in co ntrol group. These results suggest that hepatitis causes mutation in t he pre-core lesion genome of duck hepatitis B virus.