Which of the following statements about the brown stomach worm is correct?

• A. It requires an insect intermediate host to complete its life cycle.
• B. It is a virus that infects the stomach lining of mammals.
• C. It is a parasite with a direct life cycle, meaning it does not require an intermediate host.
• D. It is a free-living nematode found in soil.

Answer: (C)

Verified step by step guidance

1. Identify the organism in question: the brown stomach worm, which is a parasitic nematode affecting the stomach of certain mammals.
2. Understand the life cycle types of parasites: a direct life cycle means the parasite does not require an intermediate host, while an indirect life cycle involves one or more intermediate hosts.
3. Recall that the brown stomach worm (e.g., Ostertagia ostertagi) has a direct life cycle, where infective larvae are ingested by the host and develop into adults in the stomach without needing an insect or other intermediate host.
4. Eliminate incorrect options by recognizing that the brown stomach worm is not a virus, nor is it free-living in soil; it is a parasitic nematode.
5. Conclude that the correct statement is the one describing the brown stomach worm as a parasite with a direct life cycle, not requiring an intermediate host.