What is an intermediate host?

What is an intermediate host?

• A. A host in which the parasite completes its entire life cycle
• B. A host that gives food and shelter to immature stages of a parasite
• C. An organism that resists infection
• D. A host that only transmits viruses

Answer: (B)

An intermediate host is a host in which a parasite undergoes development through larval or immature stages, but does not reach sexual maturity there. This stage is essential for the parasite to progress to an infectious form that can move on to the final host, where the adult parasite lives and reproduces. That’s why describing a host that provides food and shelter to immature stages fits perfectly—it highlights the role of the host in enabling development rather than completing the life cycle. For example, many parasites use intermediate hosts to harbor larval forms before reaching their definitive host. In contrast, a host where the parasite completes its entire life cycle would be the definitive host; a host that resists infection isn’t about the parasite’s development; and a host that only transmits viruses describes a virus vector, not a parasite’s developmental stages.

An intermediate host is a host in which a parasite undergoes development through larval or immature stages, but does not reach sexual maturity there. This stage is essential for the parasite to progress to an infectious form that can move on to the final host, where the adult parasite lives and reproduces. That’s why describing a host that provides food and shelter to immature stages fits perfectly—it highlights the role of the host in enabling development rather than completing the life cycle.

For example, many parasites use intermediate hosts to harbor larval forms before reaching their definitive host. In contrast, a host where the parasite completes its entire life cycle would be the definitive host; a host that resists infection isn’t about the parasite’s development; and a host that only transmits viruses describes a virus vector, not a parasite’s developmental stages.