The disease which is caused by helminth parasite of man's blood that has an intermediate host of snail is ?

Options

A. Liver rot
B. Bilharzia
C. Ascariasis
D. Filariasis

Answer

To solve the question regarding the disease caused by a helminth parasite of man's blood with an intermediate host of a snail, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Type of Parasite**:
- The question specifies a helminth parasite. Helminths are worms, and they can be classified into different groups such as flatworms (trematodes and cestodes) and roundworms (nematodes).

2. **Determine the Host**:
- The definitive host mentioned is humans, which means the adult form of the parasite lives in humans. The intermediate host is a snail, which is crucial for the life cycle of the parasite.

3. **Consider the Options**:
- The options provided are liver rot, bilharzia, ascariasis, and filariasis.
- We need to analyze each option to see which one fits the criteria of being a helminth that has a snail as an intermediate host.

4. **Analyze Each Option**:
- **Liver Rot**: Caused by Fasciola hepatica (liver fluke), which does involve a snail as an intermediate host but does not inhabit the blood.
- **Bilharzia**: Also known as schistosomiasis, caused by the genus Schistosoma, which is a blood fluke. This parasite has a snail as an intermediate host and resides in the blood of humans.
- **Ascariasis**: Caused by Ascaris lumbricoides, which does not have an intermediate host; it is a direct life cycle parasite.
- **Filariasis**: Caused by filarial worms (e.g., Wuchereria bancrofti), which have mosquitoes as intermediate hosts, not snails.

5. **Conclusion**:
- The only option that matches all the criteria (helminth, blood-dwelling, snail intermediate host) is **Bilharzia** (schistosomiasis).

### Final Answer:
The disease caused by a helminth parasite of man's blood that has an intermediate host of a snail is **Bilharzia** (or schistosomiasis).

---