An intermediate host is absent in case of parasite

Options

A. Liver fluke
B. Tapeworm
C. Ascaris
D. Plasmodium

Answer

To solve the question regarding which parasite does not have an intermediate host, we will analyze the options given and determine the life cycle of each parasite mentioned.

### Step-by-Step Solution:

1. **Understand the Concept of Intermediate Hosts**:
- An intermediate host is a host that harbors the larval or immature stages of a parasite. The parasite typically requires one or more intermediate hosts to complete its life cycle.

2. **Analyze the First Example - Liver Fluke**:
- The liver fluke is a type of flatworm (phylum Platyhelminthes).
- It requires two intermediate hosts: a snail (for the larval stage) and a sheep (for the adult stage).
- Therefore, the liver fluke does have intermediate hosts.

3. **Analyze the Second Example - Tapeworm**:
- Tapeworms also belong to the phylum Platyhelminthes.
- They require a pig (intermediate host) and a human (definitive host) to complete their life cycle.
- Hence, tapeworms also have intermediate hosts.

4. **Analyze the Third Example - Ascaris**:
- Ascaris is a roundworm belonging to the phylum Nematoda (or Aschelminthes).
- It completes its life cycle entirely within a single host, which is typically a human.
- Ascaris does not require any intermediate host to develop, making it unique among the examples provided.

5. **Analyze the Fourth Example - Plasmodium**:
- Plasmodium is a protozoan parasite responsible for malaria.
- It has two hosts: the mosquito (primary host) and humans (secondary host).
- Therefore, Plasmodium does have intermediate hosts.

6. **Conclusion**:
- Among the parasites discussed, Ascaris is the only one that does not have an intermediate host. It is classified as a monogenetic parasite because it completes its life cycle in a single host.

### Final Answer:
- The parasite that does not have an intermediate host is **Ascaris**.