The multiplication of poliovirus in lymphoid cells of the intestines suggests involvement of which tissue type?

• A. Bone marrow
• B. Gut-associated lymphoid tissue
• C. Liver tissue
• D. Heart tissue

Answer: (B)

The key idea is that poliovirus is an enterovirus that first multiplies in the gut-associated lymphoid tissue of the intestinal mucosa. It targets lymphoid cells in structures like the Peyer’s patches, which are part of the immune system in the lining of the intestine. The virus can cross the intestinal barrier via M cells and establish replication in this lymphoid tissue, which helps explain the enteric phase of infection and how the virus can enter the bloodstream to cause viremia and, in some cases, spread to the nervous system. Other tissues listed aren’t typical sites of productive poliovirus replication—bone marrow isn’t a primary replication site for this virus, and liver or heart tissue aren’t characteristically involved in its multiplication.