Question

Draw a clean and labelled diagram of the life-cycle of malaria parasite.

Hint:

Remember: Malaria parasite completes its life cycle in two hosts – human (asexual cycle) and mosquito (sexual cycle).

Answer 1

The malaria parasite is caused by Plasmodium (e.g., Plasmodium vivax, Plasmodium falciparum). Its life cycle involves two hosts: human (primary host) and female Anopheles mosquito (secondary host).

Step 1: Stages in human host. \[\begin{array}{rl} 1. & \text{Sporozoites are injected into the blood by the bite of female Anopheles mosquito.} \\ 2. & \text{They travel to the liver, undergo schizogony, and form merozoites.} \\ 3. & \text{Merozoites infect RBCs, multiply, and rupture them, releasing toxins (causing fever and chills).} \\ 4. & \text{Some merozoites develop into gametocytes.} \\ \end{array}\]

Step 2: Stages in mosquito host. \[\begin{array}{rl} 1. & \text{When the mosquito bites an infected person, gametocytes enter its gut.} \\ 2. & \text{Male and female gametes fuse to form zygote.} \\ 3. & \text{Zygote develops into ookinete $\rightarrow$ oocyst $\rightarrow$ thousands of sporozoites.} \\ 4. & \text{Sporozoites migrate to salivary glands, ready to infect another human.} \\ \end{array}\]