Question

Carrier of malaria-causing protozoan is

A. Female Anopheles mosquito

B. Cockroach

C. Housefly

D. Butterfly

Answer 1

Hint: Malaria is a life-threatening disease transmitted through the bite of an infected mosquito that carries the Plasmodium parasite.

Complete answer:

Malaria is caused by Plasmodium that is transmitted from an infected individual to a healthy individual through a female Anopheles mosquito carrier. As the Plasmodium parasite is present in the blood of the infected human it easily gets transferred to the mosquito along with blood. Plasmodium survives in the mosquito for a few days and when a mosquito bites the next human, it is transferred from mosquito to the human through the saliva of the mosquito bite. Symptoms of malaria include fever, chills, body aches, nausea, vomiting, and headache.

Additional Information:

> Plasmodium parasite involves two hosts during its life cycle. Though it has an effect on one of its hosts (humans), where it causes malaria. The 2nd host (mosquito) does not have any effects due to the presence of these parasites. 

> Plasmodium parasite grows and multiplies in the liver cells of the human host and then moves to red blood cells (RBCs). 

> Through RBCs, it enters the bloodstream, where it further grows in RBCs to form broods of the parasite. These broods of parasite destroy the RBCs and release the newly formed Plasmodium offspring are called Merozoites. 

> Merozoites then continue their life cycle by infecting other healthy RBCs, where they again brood, and some of them become the male and female gametocytes.

> The mature Plasmodium gametocytes from the infected human blood are transferred into the mosquito through the ingestion of blood by female Anopheles mosquito. 

> The Plasmodium gametocytes undergo fertilization in the gut of the mosquito and begin its new life cycle of growth and multiplication. 

> After around 10-18 days sporozoite (a stage of Plasmodium parasite) moves to the salivary gland of the mosquito. These sporozoites stay in the salivary gland until the mosquito feeds on another human. 

> On mosquito bite, the parasitic sporozoite is injected into the human along with the mosquito saliva. Once into the blood, the sporozoites move to the liver and begin a new cycle.

Figure: The life cycle of the Plasmodium parasite.

Note: Malaria is caused by Plasmodium species like P. falciparum, P. malariae, P. vivax, and P. knowlesi. Plasmodium species are the microscopic parasites that can be transmitted only by female Anopheles mosquitoes as they need nutrients to nurture their eggs, and these nutrients they get from human blood. Whereas male mosquitoes only feed on sugars and carbohydrates for their nutritional requirements, which they mostly get from plants.