Infectivity develops in microfilariae inside

Options

A. Human liver
B. Human spleen
C. Mosquito haemolymph
D. Mosquito muscles

Answer

To answer the question "Infectivity develops in microfilariae inside," we will analyze the options provided and explain the correct answer step by step.

### Step-by-Step Solution:

1. **Understanding Microfilariae**: Microfilariae are the larval stage of certain parasitic nematodes (roundworms) that are transmitted by mosquitoes. They are found in the bloodstream of infected hosts.

2. **Ingestion by Mosquitoes**: When a mosquito feeds on the blood of an infected host, it ingests the microfilariae along with the blood meal.

3. **Migration in Mosquito**: After ingestion, the microfilariae penetrate the gut wall of the mosquito. This is a crucial step as it allows them to move to the next stage of their life cycle.

4. **Development in Thoracic Muscles**: Once the microfilariae have penetrated the gut wall, they migrate to the thoracic muscles of the mosquito. This is where they undergo further development.

5. **Molting Process**: Inside the thoracic muscles, the microfilariae grow and undergo two molts. This process transforms them into the infective third-stage larvae.

6. **Time Frame**: The transformation from microfilariae to infective larvae takes approximately 10 to 14 days within the mosquito.

7. **Correct Answer**: Based on the above steps, the correct answer to the question is "mosquito muscles," as this is where the infectivity develops in microfilariae.

### Final Answer:
Infectivity develops in microfilariae inside the **mosquito muscles**.

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