Why does the mosquito spread malaria?

Mosquitoes spread malaria through a complex biological process involving the transmission of the Plasmodium parasite. Here's a step-by-step explanation of how mosquitoes spread malaria:

1. Infection in Humans:

a) An infected female Anopheles mosquito bites a human and draws blood.

b) During the bite, the mosquito injects sporozoites, a form of the malaria parasite, into the bloodstream of the human.

2. Development in the Liver:

a) The sporozoites travel through the bloodstream and reach the liver.

b) Inside the liver, the sporozoites mature into schizonts, which reproduce asexually, creating thousands of merozoites.

3. Red Blood Cell Invasion:

a) The schizonts rupture, releasing merozoites into the bloodstream.

b) Merozoites invade red blood cells and begin to multiply asexually, further increasing their numbers.

4. Symptoms of Malaria:

a) The multiplication of merozoites within red blood cells causes the symptoms of malaria, such as fever, chills, sweats, headache, muscle pain, and fatigue.

b) The rupturing of red blood cells can also lead to anemia.

5. Gametocyte Formation:

a) Some of the merozoites develop into gametocytes (male and female sex cells) within the red blood cells.

6. Mosquito Bite and Transmission:

a) When another Anopheles mosquito bites an infected person, it ingests the gametocytes along with the blood meal.

b) Inside the mosquito's gut, the gametocytes mature, mate, and form a zygote, which develops into an ookinete.

7. Sporozoite Formation:

a) The ookinete penetrates the mosquito's midgut wall and develops into an oocyst, which contains thousands of sporozoites.

b) The oocyst ruptures, releasing the sporozoites into the mosquito's salivary glands.

8. Transmission during Mosquito Bite:

a) When the infected mosquito bites another human, the sporozoites are injected into the person's bloodstream, thus starting a new cycle of malaria infection.

9. Multiple Transmission Cycles:

a) A single infected mosquito can transmit malaria to multiple people through subsequent bites.

b) This is why controlling the mosquito population and preventing mosquito bites are crucial in reducing malaria transmission.

10. Geographic Distribution:

a) Malaria is primarily transmitted in tropical and subtropical regions of the world where Anopheles mosquitoes are present.

b) Factors such as climate, stagnant water, and poor sanitation contribute to the prevalence of malaria in certain areas.