Question:hard
Which of these is a calicivirus?
Which of these is a calicivirus?
Show Hint
HEV was historically grouped with Caliciviridae due to its size and shape, though it is now placed in its own family, Hepeviridae.
Updated On: Jul 8, 2026
- HAV
- HBV
- HCV
- HEV
Show Solution
The Correct Option is D
Solution and Explanation
Step 1: Recall each hepatitis virus's genome type.
HAV is a small RNA virus in the picornavirus family, the same broad group as poliovirus. HBV is unusual among these four because it carries DNA, not RNA, and belongs to the hepadnavirus family. HCV is an RNA virus in the flavivirus family, related to viruses like yellow fever virus.
Step 2: Zoom in on HEV's shape and history.
HEV is a small, naked (non-enveloped) RNA virus. Under the electron microscope, it looked so similar in size and surface structure to the caliciviruses, a family better known for causing gastroenteritis (like Norwalk virus), that it was classified with them for years.
Step 3: Mention the modern update.
Gene sequencing later showed HEV's genetic makeup does not really match the caliciviruses closely enough, so it was pulled out into its own family called Hepeviridae. This is purely a taxonomy update; it does not change how HEV causes disease or how this exam question is meant to be answered, since it is the only one of the four ever linked to the calicivirus family in the first place.
Step 4: Conclude.
Of HAV, HBV, HCV and HEV, only HEV has ever carried the calicivirus label.
$\boxed{\text{HEV}}$
HAV is a small RNA virus in the picornavirus family, the same broad group as poliovirus. HBV is unusual among these four because it carries DNA, not RNA, and belongs to the hepadnavirus family. HCV is an RNA virus in the flavivirus family, related to viruses like yellow fever virus.
Step 2: Zoom in on HEV's shape and history.
HEV is a small, naked (non-enveloped) RNA virus. Under the electron microscope, it looked so similar in size and surface structure to the caliciviruses, a family better known for causing gastroenteritis (like Norwalk virus), that it was classified with them for years.
Step 3: Mention the modern update.
Gene sequencing later showed HEV's genetic makeup does not really match the caliciviruses closely enough, so it was pulled out into its own family called Hepeviridae. This is purely a taxonomy update; it does not change how HEV causes disease or how this exam question is meant to be answered, since it is the only one of the four ever linked to the calicivirus family in the first place.
Step 4: Conclude.
Of HAV, HBV, HCV and HEV, only HEV has ever carried the calicivirus label.
$\boxed{\text{HEV}}$
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