Stage of the life history of liver fluke when it infects the intermediate host is

Options

A. Metacercaria
B. Cysticercus
C. Rhabditiform
D. Miracidium

Answer

To answer the question about the stage of the life history of the liver fluke that infects the intermediate host, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Life Cycle of Liver Fluke**: The liver fluke, scientifically known as Fasciola, has a complex life cycle that involves multiple stages and hosts.

2. **Identifying the Hosts**: The liver fluke has a definitive host (usually a mammal, such as a human or sheep) and an intermediate host (in this case, a snail).

3. **Stages of Development**: The life cycle begins with the eggs of the liver fluke, which hatch into a larval stage known as the miracidium.

4. **Infection of the Intermediate Host**: The miracidium larva is the stage that infects the intermediate host, which is the snail. This larva actively seeks out and penetrates the snail.

5. **Further Development in the Intermediate Host**: Once inside the snail, the miracidium transforms and develops into other larval forms, including sporocysts and rediae, before eventually producing the next larval stage, known as cercariae.

6. **Conclusion**: Therefore, the stage of the life history of the liver fluke that infects the intermediate host (the snail) is the **miracidium larva**.

### Final Answer:
The stage of the life history of the liver fluke when it infects the intermediate host is the **miracidium larva**.

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