Interval between the entry of sporozoites into human blood and the first appearance of malarial symptoms is known as

Options

A. cycle of Golgi
B. incubation period
C. sporogony
D. erythrocyte cycle.

Answer

To solve the question regarding the interval between the entry of sporozoites into human blood and the first appearance of malarial symptoms, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**: The question is asking about a specific term related to the lifecycle of the malaria parasite, specifically the time taken from when the sporozoites enter the human bloodstream until the first symptoms of malaria appear.

2. **Identify the Key Terms**: The key terms in the question are "sporozoites," "human blood," "malarial symptoms," and "interval."

3. **Recall the Lifecycle of Malaria**:
- The malaria parasite, Plasmodium, is transmitted to humans through the bite of an infected female Anopheles mosquito, which injects sporozoites into the bloodstream.
- After entering the bloodstream, sporozoites migrate to the liver, where they multiply before entering red blood cells (RBCs).

4. **Define the Interval**: The interval between the entry of sporozoites and the appearance of symptoms is the time taken for the parasite to multiply and cause noticeable effects in the host.

5. **Identify the Correct Term**:
- The term that describes this interval is known as the **incubation period**. This period can vary from 7 to 30 days depending on various factors such as the specific species of Plasmodium and the individual's immune response.

6. **Eliminate Other Options**:
- **Cycle of Golgi**: This refers to the distribution and multiplication of Golgi bodies during cell division, not related to the malaria lifecycle.
- **Sporogony**: This is the sexual phase of the malaria parasite's lifecycle, occurring in the mosquito, not in humans.
- **Erythrocyte Cycle**: This refers to the phase when the parasite multiplies within red blood cells, which occurs after the incubation period.

7. **Conclusion**: Based on the understanding of the lifecycle of malaria and the definitions of the terms, the correct answer to the question is **incubation period**.

### Final Answer:
The interval between the entry of sporozoites into human blood and the first appearance of malarial symptoms is known as the **incubation period**.

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