What are the two main groups of endoparasites?

• A. Helminths and protozoa
• B. Bacteria and viruses
• C. Fungi and algae
• D. Plants and animals

Answer: (A)

Endoparasites are organisms that live inside the host. The two main groups are helminths and protozoa. Helminths are multicellular worms such as nematodes (roundworms), cestodes (tapeworms), and trematodes (flukes). Protozoa are single-celled parasites like Giardia, Plasmodium, and Entamoeba. These groups cover the majority of internal parasites you’ll encounter in veterinary practice and can inhabit a range of sites from the gut to the blood and tissues.

Bacteria and viruses are microbes that can cause infections inside hosts, but they aren’t classified as the two primary endoparasite groups. Fungi and algae aren’t the main endoparasite categories used in this context, and plants and animals aren’t endoparasites themselves (the host is typically an animal, while plants are not the usual endoparasite category).