What are helminths?

• A. Bacteria and viruses
• B. Worms such as nematodes and cestodes
• C. Protozoa
• D. Plants and fungi

Answer: (B)

Helminths are parasitic worms—multicellular organisms that live in or on a host and derive nutrients from it. The main groups of helminths include nematodes (roundworms) and cestodes (tapeworms), which is why the described option fits best. They are macroscopic compared with bacteria, viruses, and protozoa, and you often encounter them as larger parasites in the gastrointestinal tract or tissues. In contrast, bacteria and viruses are microscopic microbes, protozoa are single-celled organisms, and plants and fungi are separate kingdoms that are not classified as helminths. Understanding that helminths are worms helps in recognizing infections like roundworm or tapeworm infections, which are usually diagnosed by finding eggs or larvae in stool or by identifying adult worms, and treated with specific antiparasitic medications.