Question

The infective stage of malarial parasite, Plasmodium that enters human body is

• A. merozoite
• B. sporozoite
• C. trophozoite
• D. minuta form.

Answer 1

The Correct Option is B

The question is asking about the infective stage of the malarial parasite, Plasmodium, that enters the human body. To answer this, let's examine the lifecycle of the Plasmodium parasite.

The Plasmodium parasite, responsible for malaria, undergoes a complex lifecycle that includes different stages in both humans and mosquitoes. Understanding the lifecycle helps us identify the infective stage that enters the human body.

1. Sporozoites: These are the infective forms of the parasite that are injected into the human bloodstream by an infected female Anopheles mosquito during a blood meal. Once inside the human body, sporozoites travel to the liver, where they invade liver cells and multiply.
2. Merozoites: After multiplying in the liver, the sporozoites eventually develop into merozoites. These merozoites are released into the bloodstream, where they infect red blood cells and lead to the symptoms of malaria.
3. Trophozoites: This stage occurs when merozoites inside the red blood cells mature into trophozoites. These trophozoites develop further into schizonts, which eventually rupture and release more merozoites.
4. Minuta Form: This term is not specific to the lifecycle of Plasmodium; it might refer to various forms in parasitology but does not typically apply to Plasmodium infections.

Based on the above explanation, it is clear that the stage of the Plasmodium parasite that is infective to humans—the stage that enters the human body—is the sporozoite stage.

Conclusion: The correct answer is sporozoite, as this is the stage that is transmitted from the mosquito to humans and initiates the infection cycle.