Which family and genus does poliovirus belong to, and what is its genome type?

• A. Picornaviridae family, Enterovirus genus; non-enveloped, positive-sense single-stranded RNA virus.
• B. Flaviviridae family, Flavivirus genus; enveloped, positive-sense RNA virus.
• C. Orthomyxoviridae family, Influenzavirus genus; enveloped, negative-sense RNA virus.
• D. Reoviridae family, Rotavirus genus; non-enveloped, double-stranded RNA virus.

Answer: (A)

Poliovirus belongs to the Picornaviridae family, in the Enterovirus genus, and it is a non-enveloped, positive-sense single-stranded RNA virus. This means its RNA genome can act directly as mRNA in the host cell to produce viral proteins, and the virus lacks a lipid envelope, contributing to its stability outside the host. In contrast, the other families listed are either enveloped or have different genome types (for example, enveloped positive-sense RNA like flaviviruses, enveloped negative-sense RNA like orthomyxoviruses, or non-enveloped double-stranded RNA like reoviruses), which do not apply to poliovirus.