Life cycle

Question 1

what steps are there in the plasmodium lifecycle

Answer 1

1. Mosquito Bite - sporozoites injected
2. Liver Stage - hepatocyte to merozoite
3. Transition to Blood Stage - merozoites invasion of RBCs
4. Blood Stage (Symptomatic Phase)
   (ring stage- trophozoite - shizont)
5. Schizonts burst to release merozoites.
6. Taken up by mosquitos, form gametocytes and eventually sporozoites

cycle restarts

Question 2

Mosquito Bite (Infection Begins):

Answer 2

female Anopheles mosquito injects saliva containing sporozoites into a human during a bite.

saliva stops clotting,

Question 3

liver stage

Answer 3

Liver Stage

Sporozoites travel in peripheral blood to the liver.
Enter through Kupffer cells and infect hepatocytes (liver cells), sometimes killing cells en route.
Parasites undergo nuclear divisions, copying DNA and forming thousands of merozoites.

Question 4

transition to Blood Stage

Answer 4

Merozoites leave the liver, enter the bloodstream, and infect red blood cells (RBCs).

Question 5

Blood Stage (Symptomatic Phase)

Answer 5

In RBCs: Parasites progress through stages:
Ring stage → Pigmented trophozoites → Schizonts (multiple nuclei).
Schizonts burst infected RBCs every 48 hours, releasing merozoites (up to 32 per RBC), which infect new RBCs.

at ring stage, some differentiate into gametocytes

This cycle repeats every 48 hours, causing malaria symptoms (fever, chills, anemia).

Question 6

Mosquito Infection (Transmission to Mosquito):

Answer 6

When another mosquito bites an infected human, it ingests gametocytes (sexual forms of the parasite).

Question 7

Mosquito Stage:

Answer 7

Gametocytes in the mosquito’s stomach develop into male and female forms, fertilize, and form a zygote.
The zygote becomes a motile ookinete, which penetrates the mosquito’s stomach lining and forms a cyst (oocyst) on the outer stomach wall.
The oocyst produces thousands of sporozoites, which migrate to the mosquito’s salivary glands.
Cycle Restarts:

During the mosquito’s next bite, sporozoites are injected into a new human host, restarting the cycle.