This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'Active replication in Hepatitis B infection is indicated by? \nSelect and explain. \nA. HBeAg, B. HBsAg, C. HBcAg, D. Anti-HBsAg', 'role': 'user'}, {'content': "Answer: A \nExplanation: o HBeAg is an indicator of active intrahepatic replication and high infectivity.\no It is a qualitative marker of HBV replication.\nSerologic and virologic markers of HBV infection\n1. HBs Ag\no First virological marker detectable in the serum\no HBsAg presence precedes elevations of serum aminotrans ferase activity and onset of clinical illness,\no HBsAg become undetectable 1-2 months after the onset of jaundice and rarely persists beyond 6\nmonths,\no In chronic HBV infection, HBsAg remains detectable beyond 6 months.\n2. HRcAg\no It is not demonstrable in the circulation because it is enclosed within the HBs Ag coat,\no HBc Ag remain in the hepatocyte, where it can readily be detectable by immunohistochemical staining.\n3. HBeAg\no HBe Ag appears concurrently with or shortly after HBs Ag.\no HBe Ag is an indicator of active intrahepatic replication and high infectivity.\no It is a qualitative marker of HBV replication.\no HBs Ag carrier mothers who are HBe Ag positive almost invariably (> 90%) transmit hepatasis B infection\nTo their offspring, where as HBs Ag carrier mothers with an\xa0HBe rarely (10 to 15%) infect their\noffspring.\no HBe testing is indicated primarily during follow up of chronic infection.\n4. And HBc Ag\no Appears w ithin the first 1 to 2 weeks after the appearance of HBs Ag.\no In acute or recent infection IgM an HBc is detected.\no IgG an\xa0HBc indicates remote infection.\n5. An\xa0HBsAg\no It becomes detectable in blood when HBs Ag disappears,\no An\xa0HBs Ag is protective \xa0antibody.\no It is the only serological marker, present after immunization.\n6. An\xa0HBeAg\no Disappearance of HBe Ag is followed by the appearance of anHBeAg.\no Its presence indicates low infectivity' and virus replication.\n7. HBVDNA\no it is the quantitative marker of virus replication", 'role': 'assistant'}]