A 34-year-old man comes to the emergency department due to 5 days of progressive anorexia, nausea, and abdominal pain. The patient is a known hepatitis B carrier. He admits to using IV drugs and has shared needles with other drug users on several occasions. His temperature is 37.7 C (99.9 F). Examination shows scleral icterus and mild, tender hepatomegaly. Laboratory studies are notable for highly elevated levels of liver aminotransferases and serum bilirubin and also show the following results:
Hepatitis B surface antigen positive Hepatitis C virus antibody negative HIV-1 antibody negative Hepatitis D RNA positive
This patient's chronic infection assists which of the following life cycle aspects of the current infectious agent?
Often referred to as the delta agent, hepatitis D virus (HDV) is a 35-nm, double-shelled particle that resembles the Dane particle of hepatitis B virus (HBV). The internal polypeptide assembly of HDV is designated hepatitis D antigen (HDAg). Associated with this antigen is a very short, circular molecule of single-stranded RNA. HDAg is considered replication defective as it must be coated by the external coat hepatitis B surface antigen (HBsAg) of HBV to penetrate the hepatocyte. HDV infection can arise either as an acute coinfection with HBV or as a superinfection of a chronic HBV carrier.
(Choices B, C, D, and E) Once coated with HBsAg, HDV is able to penetrate the hepatocyte, survive within the cell, integrate into the host genome, replicate its viral RNA, and translate its genome into protein.
Educational objective:
The hepatitis B surface antigen of hepatitis B virus must coat the hepatitis D antigen of hepatitis D virus before it can infect hepatocytes and multiply.