Infectivity of HBV is indicated by

Ans. is 'a' i.e., HBeAg Serologic and virologic markers of HBV infection HBs Ag First virological marker detectable in the serum HBsAg presence precedes elevations of serum aminotransferase activity and onset of clinical illness. HBsAg become undetectable 1-2 months after the onset of jaundice and rarely persists beyond 6 months. In chronic HBV infection, HBsAg remains detectable beyond 6 months. HBc Ag It is not demonstrable in the circulation because it is enclosed within the HBs Ag coat. HBc Ag remain in the hepatocyte, where it can readily be detectable by immunohistochemical staining. HBe Ag HBe Ag appears concurrently with or sholy after HBs Ag. HBe Ag is an indicator of active intrahepatic replication and high infectivity. It is a qualitative marker of HBV replication. HBs Ag carrier mothers who are HBeAg positive almost invariably (> 90%) transmit hepatitis B infection to their offspring, where as HBs Ag carrier mothers with anti HBe rarely (10 to 15%) infect their offspring. HBe testing is indicated primarily during follow up of chronic infection. Anti HBc Ag o Appears within the first 1 to 2 weeks after the appearance of HBs Ag. In acute or recent infection IgM anti HBc is detected. Ig G anti HBc indicates remote infection. Anti HBs Ag o It becomes detectable in blood when HBs Ag disappears. It is the only serological marker, present after immunization. Anti HBs Ag is protective antibody. nti HBe Ag o Disappearance of HBe Ag is followed by the appearance of anti HBe Ag. Its presence indicates low infectivity and virus replication. HBV DNA o It is the quantitative marker of virus replication.