Question

In the life cycle of a {Plasmodium, once the sporozoite enters the blood of the host, it invades the hepatic portal system, resulting in occurrence of change in the host body, leading to malaria
A. Sporozoite enters the hepatocytes and divides by schizogony leading to formation of cryptomerozoites
B. Inside RBCs, the micro-metacryptozoites become rounded and modify into a young trophozoites.
C. As the trophozoite grows in size, a central vacuole is developed so that the nucleus is pushed to one side into the peripheral cytoplasm, leading to amoeboid stage.
D. In Amoeboid stage the small red eosinophils granules appear in the cytoplasm of the host corpulses as Schuffner's granules}
Choose the most appropriate answer from the options given below:

• A. A, B and D only
• B. A, B and C only
• C. A, B, C and D
• D. B, C and D only

Hint:

To understand the {Plasmodium} life cycle in humans, break it down:

\textbf{Liver Stage (Exo-erythrocytic):} Sporozoite \(\rightarrow\) Hepatocyte \(\rightarrow\) Schizont \(\rightarrow\) Merozoites.
\textbf{Blood Stage (Erythrocytic):} Merozoite \(\rightarrow\) RBC \(\rightarrow\) Trophozoite (ring, amoeboid) \(\rightarrow\) Schizont \(\rightarrow\) New Merozoites (cause fever) OR Gametocytes (infect next mosquito).
This framework helps organize the sequence of events.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The question asks to identify the correct statements describing the events in the life cycle of {Plasmodium} (the malaria parasite) after it enters the human host. The life cycle in humans has two main phases: the exo-erythrocytic (liver) stage and the erythrocytic (red blood cell) stage.

Step 2: Analyzing each statement:
- Statement A: True. When a mosquito injects sporozoites into the human bloodstream, they travel to the liver and invade liver cells (hepatocytes). Inside these cells, they undergo asexual multiplication (schizogony) to produce thousands of merozoites (referred to as cryptomerozoites or metacryptozoites). This is the pre-erythrocytic or exo-erythrocytic cycle.
- Statement B: True. After the liver stage, merozoites (specifically metacryptozoites) are released into the blood and invade red blood cells (RBCs). Inside the RBC, the parasite transforms into a feeding stage called a trophozoite. This begins the erythrocytic cycle.
- Statement C: True. The young trophozoite develops a large food vacuole, which consumes hemoglobin. This vacuole pushes the parasite's nucleus and cytoplasm to the periphery, creating a characteristic "signet ring" appearance. As the parasite grows, it becomes larger and more irregular in shape, known as the amoeboid stage. The description is accurate.
- Statement D: True. In infections caused by certain species like {Plasmodium vivax} and {P. ovale}, the cytoplasm of the infected RBC develops characteristic fine, eosinophilic (reddish) dots known as Schuffner's granules or dots. This is a key diagnostic feature.

Step 3: Final Answer:
All four statements (A, B, C, and D) correctly describe different stages and events that occur during the life cycle of the malaria parasite in the human host. Therefore, the most appropriate answer includes all of them.