Which of the following statements about the adeno-associated virus (AAV) and the delta agent is correct?

• A. AAV is a virus, and the delta agent is a subviral agent associated with hepatitis D.
• B. AAV is a virus, while the delta agent is a viroid.
• C. Both AAV and the delta agent are classified as viroids.
• D. Both AAV and the delta agent are prions.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the nature of Adeno-Associated Virus (AAV). AAV is a small virus that requires a helper virus to replicate. It is classified as a virus because it contains DNA and protein capsid, and it can infect human cells.
2. Step 2: Understand the delta agent, also known as Hepatitis D virus (HDV). The delta agent is a subviral agent because it requires the presence of Hepatitis B virus to replicate. It is not a full virus on its own but depends on another virus for its life cycle.
3. Step 3: Differentiate between viruses, viroids, and prions. Viruses contain nucleic acid (DNA or RNA) and protein coat, viroids are small infectious RNA molecules without a protein coat (mostly infect plants), and prions are infectious proteins without nucleic acids.
4. Step 4: Recognize that AAV is a virus because it has DNA and a protein coat, while the delta agent is a subviral agent associated with hepatitis D, not a viroid or prion.
5. Step 5: Conclude that the correct statement is: 'AAV is a virus, and the delta agent is a subviral agent associated with hepatitis D.'