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 123/900 IU/ml. The serological tests showed presence of HBsAg, IgM anti-HBc and HBeAg. The most likely diagnosis is: