MLT GlobeVirology: Hepatitis viruses – page 2
42 Virology MCQs on Hepatitis viruses with answers and explanations.
Hepatitis D virus can infect only people who also have hepatitis B because HDV needs:
HDV is a defective RNA virus that uses HBsAg as its envelope. It occurs as co-infection with HBV or superinfection of a chronic HBsAg carrier.
Which test confirms acute hepatitis A infection?
IgM anti-HAV is present at symptom onset and lasts about 3–6 months. IgG or total antibody may reflect past infection or vaccination.
Chronic hepatitis B infection is defined by persistence of HBsAg in serum for more than:
HBsAg that remains positive beyond 6 months indicates chronic infection.
Against which of these viruses is there currently no licensed vaccine in routine use?
Hepatitis C is prevented by blood safety measures and treated with antivirals, but no vaccine exists; hepatitis A, hepatitis B and measles vaccines are routinely used.
Which statement correctly compares hepatitis B virus and hepatitis C virus?
HCV is a positive-sense ssRNA flavivirus (Hepacivirus). HBV is a partially double-stranded DNA virus that often becomes chronic; neither is isolated by routine culture.
Which statement about viral hepatitis is FALSE?
Anti-HCV EIA is the standard screening test, confirmed by HCV RNA. HDV is a defective virus using HBsAg as its coat, and alcohol accelerates HCV liver disease.
Which statement about hepatitis A virus is INCORRECT?
Acute hepatitis A is diagnosed by detecting IgM anti-HAV; HAV grows poorly in culture. Children usually have silent infection, and immune globulin or vaccine gives post-exposure protection.
Which feature best characterises hepatitis C virus infection?
About 55-85% of HCV infections become chronic, risking cirrhosis and HCC. HCV is an RNA flavivirus, and donated blood is screened by anti-HCV and NAT.
During the "window" phase of hepatitis B, HBsAg has disappeared but anti-HBs is not yet detectable. Which marker may be the only positive one?
Anti-HBc (IgM) remains positive throughout the window between HBsAg loss and anti-HBs appearance; blood banks test anti-HBc for this reason.
Which hepatitis B antigen is found in infected hepatocyte nuclei but is not normally detectable free in serum?
HBcAg forms the nucleocapsid and is enclosed within HBsAg in circulating virions, so it is not measured in serum; its antibody (anti-HBc) is. HBcAg is shown in liver tissue.
A pig farmer develops acute hepatitis after eating undercooked pork. The agent is a non-enveloped RNA virus of the family Hepeviridae. Which virus?
HEV (Hepeviridae) spreads fecal-orally and zoonotically from pigs. It was once grouped with caliciviruses, but that classification is outdated.
A screening anti-HCV ELISA gives a signal of 3.5 with a cut-off of 1.35. How should this be reported, and what follows?
A value above the cut-off is reactive for anti-HCV. Antibody does not distinguish past from current infection, so HCV RNA (NAT) is needed to confirm viraemia.
A patient has negative HBsAg and negative anti-HBs, but positive IgM anti-HBc, 3 months after acute hepatitis symptoms. This pattern represents:
In the window period HBsAg has disappeared but anti-HBs is not yet detectable. IgM anti-HBc may be the only marker showing recent infection.
HBsAg has been positive for 8 months. Total anti-HBc is positive, IgM anti-HBc is negative and anti-HBs is negative. This indicates:
HBsAg persisting beyond 6 months defines chronic infection. Absent IgM anti-HBc argues against acute infection.
A screening anti-HCV test is reactive. What is the recommended next test?
A reactive antibody result is followed by HCV RNA testing to tell current infection from past infection or a false-positive. Genotyping is done only if treatment is planned.
Anti-HCV is reactive but HCV RNA is not detected on repeat testing. This most likely means:
About a quarter of HCV infections clear on their own; antibody remains but RNA is absent. A false-positive antibody result is the other possibility.
Which hepatitis virus spread by the fecal–oral route causes a high death rate in pregnant women, especially in the third trimester?
HEV genotypes 1 and 2, spread by contaminated water, can cause fulminant hepatitis in pregnancy. HAV is also fecal–oral but does not show this high mortality in pregnancy.
After hepatitis B vaccination, which anti-HBs level is generally considered protective?
An anti-HBs level of 10 mIU/mL or more after the vaccine series shows a protective response. Healthcare workers below this may need revaccination.
After a needlestick from a source patient who is HBeAg-positive, which virus carries the HIGHEST transmission risk to a non-immune worker?
HBV from an HBeAg-positive source can transmit in up to about 30% of needlesticks in a non-immune person. Current CDC estimates are about 0.2% for HCV (older sources quoted 1.8%) and about 0.3% for HIV.
The hepatitis B virus genome is best described as:
HBV (Hepadnaviridae) has a small, partially double-stranded circular DNA genome and replicates through an RNA intermediate.