Question

The infectious stage of Plasmodium that enters the human body is

• A. Trophozoites
• B. Sporozoites
• C. Female gametocytes
• D. Male gametocytes

Answer 1

The Correct Option is B

To determine the correct answer, we need to understand the life cycle of Plasmodium, the parasite responsible for causing malaria in humans.

The life cycle of Plasmodium involves two hosts: humans and the female Anopheles mosquito. Let's delve into the stages:

1. In the Mosquito:
   • Plasmodium develops into sporozoites within the salivary glands of the mosquito.
   • When an infected mosquito bites a human, these sporozoites are transferred into the human bloodstream.
2. In Humans:
   • Sporozoites infect liver cells, where they multiply and develop into merozoites.
   • Merozoites are released into the bloodstream, where they infect red blood cells, leading to malaria's symptomatic stage.

The infectious stage of Plasmodium that enters the human body is therefore sporozoites.

Justification for Other Options:

• Trophozoites: These are the active, feeding stage of the parasite found in red blood cells, not the form that enters from mosquito bites.
• Female Gametocytes: These are the sexual forms of the parasite that develop in human red blood cells, transmitted back to the mosquito when it bites an infected person.
• Male Gametocytes: Similar to female gametocytes, these develop in human red blood cells, and their role is to fertilize female gametes inside the mosquito's gut.

Based on the above understanding, the correct answer is Sporozoites.