What is the life cycle of a protist causing malaria?

The life cycle of a malaria-causing protist involves stages in both the mosquito vector and the human host.

The malaria-causing protist, Plasmodium, has a complex life cycle that involves two hosts: the Anopheles mosquito and the human. The cycle begins when an infected mosquito bites a human, injecting Plasmodium sporozoites into the bloodstream. These sporozoites travel to the liver, where they invade liver cells and multiply asexually, producing thousands of merozoites.

After a week or two, the liver cells burst, releasing the merozoites into the bloodstream. Here, they invade red blood cells and continue to multiply asexually. This causes the red blood cells to burst, releasing more merozoites and causing the symptoms of malaria. Some merozoites develop into sexual forms called gametocytes, which can be taken up by another mosquito when it bites the infected human.

Inside the mosquito, the gametocytes mature into male and female gametes. These gametes fuse to form a zygote, which develops into an ookinete. The ookinete penetrates the mosquito's gut wall and forms an oocyst, where it multiplies to produce thousands of sporozoites. When the oocyst bursts, the sporozoites are released and travel to the mosquito's salivary glands, ready to be injected into a new human host. This completes the life cycle of the malaria-causing protist.

The life cycle of Plasmodium is a clever strategy that allows the protist to evade the human immune system and spread to new hosts. Understanding this life cycle is crucial for developing effective treatments and prevention strategies for malaria.