Question

Transfer of Taenia to secondary host occurs as

• A. oncosphere
• B. cysticercus
• C. morula
• D. egg.

Answer 1

The Correct Option is A

To determine the correct answer for the process of transferring Taenia to its secondary host, we must understand the lifecycle of Taenia, which is a genus of tapeworms.

Here is a step-by-step explanation of the life cycle:

1. Egg Stage: The life cycle begins when the eggs are released into the environment through the feces of the primary host (usually a carnivore such as a dog or human). These eggs contain embryos that are essential for infection.
2. Oncosphere: When these eggs are ingested by the secondary host (often herbivores like cattle or pigs), they hatch into larvae known as oncospheres. This stage is crucial as it represents the point where the parasite is transferred to the secondary host. The oncosphere penetrates the intestinal wall and enters the bloodstream.
3. Cysticercus: Inside the secondary host, the oncospheres develop into cysticercus (or bladderworm) stage. It is a larval form that resides in the muscles of the host.
4. Development to Adult: When the flesh of the infected secondary host is consumed by the primary host, the cysticercus develops into an adult tapeworm in the intestine of the primary host.

Given the options and this lifecycle process:

• Oncosphere: This is the larval stage that successfully transfers from the environment to the secondary host, starting the infection process in the new host. This is the correct answer.
• Cysticercus: This stage occurs after the oncosphere has penetrated the secondary host. It is not involved in the initial transfer.
• Morula: This term is not related to Taenia; it is an early embryonic stage in animals and is irrelevant to parasitic transmission.
• Egg: Before reaching the secondary host, but not the form that specifically migrates or infects the host once consumed.

Thus, the correct answer is oncosphere, as this is the form specifically involved in the infection of the secondary host.