A thirty year man presented with nausea, fever and jaundice of 5 days duration. The biochemical tests revealed a bilirubin of 6.7 mg/dl (conjugated 5.0 mg/dl) with SGOT/SGPT (AST/ALT) of 1230/ 900 IU/ml. The serological tests showed presence of HBsAg, IgM anti HBc and HBe Ag. The most likely diagnosis -