Taenia solium passes on to secondary host at which stage?

Options

A. Cydippid
B. Cysticercus
C. Onchosphere
D. Bladder worm

Answer

To determine at which stage Taenia solium passes on to its secondary host (the pig), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Secondary Host**:
- The secondary host for Taenia solium is the pig. This is important as it helps us understand where the transmission occurs.

**Hint**: Remember that the secondary host is the organism that harbors the larval stage of the parasite.

2. **Understand the Life Cycle of Taenia solium**:
- Taenia solium, also known as the pork tapeworm, has a complex life cycle that involves several stages. The adult tapeworm lives in the intestines of humans, which are the primary hosts.

**Hint**: Familiarize yourself with the different life stages of the tapeworm to understand how it transitions between hosts.

3. **Identify the Transmission Stage**:
- The transmission of Taenia solium to the pig occurs when the pig ingests the oncospheres. These oncospheres are the larval stage that is passed in the feces of infected humans.

**Hint**: Look for the specific stage of the parasite that is responsible for infecting the secondary host.

4. **Explain the Process of Infection**:
- Infected humans excrete gravid proglottids in their feces, which contain the oncospheres. When pigs consume contaminated food or garbage that includes human feces, they ingest these oncospheres.

**Hint**: Consider how the environment and feeding habits of pigs contribute to their role as secondary hosts.

5. **Confirm the Correct Stage**:
- The oncosphere is the stage at which Taenia solium passes to the secondary host (the pig). The oncosphere hatches in the pig's intestine, leading to the development of the larval form known as cysticercus.

**Hint**: Remember that the oncosphere is critical for the initial infection in the secondary host.

### Final Answer:
Taenia solium passes on to the secondary host (pig) at the **oncosphere stage**.