Question

Explain the mode of spread of malaria.

Answer 1

Malaria is caused by the protozoan parasite Plasmodium and is spread by the bite of the female Anopheles mosquito, which acts as a vector or carrier.

1. The female Anopheles mosquito feeds on human blood (the male feeds on plant juices and is harmless).
2. When it bites an infected person, it sucks up the gametocytes of Plasmodium along with the blood.
3. Sexual reproduction of the parasite occurs in the mosquito's gut and infective sporozoites develop and collect in the mosquito's salivary glands.
4. When this infected mosquito bites a healthy person, it injects the sporozoites into his blood, thus transmitting malaria.
5. Monkeys can act as reservoir hosts — malaria can spread from monkeys to man through the mosquito.

Thus malaria spreads only through the bite of an infected female Anopheles mosquito; it is not spread by contact, food or water. Prevention therefore depends on preventing mosquito bites (nets, repellents, insecticides) and destroying breeding places (stagnant water, DDT, kerosene, larvivorous fish like Gambusia).