Question

Infective stages of malarial parasite are found in?
A. Salivary glands of mosquito
B. Intestine of mosquito
C. Haemolymph of mosquito
D. Stomach wall of mosquito

Answer 1

Hint: Female anopheles acts as a carrier for the malaria parasite i.e. Plasmodium protozoa, larvae of anopheles found in freshwater.

Complete answer:
Malaria is a mosquito-borne contagious disease caused by the species of the parasitic protozoan microorganisms known as Plasmodium. Malaria vector i.e. female anopheles mosquito transmits the malarial parasites into the host. The malaria parasite exists in the form of a motile sporozoite which is an infective stage of malaria present in the salivary glands of mosquitoes. Plasmodium requires two hosts to complete its life cycle i.e. vertebrate intermediate host (Human) and definitive host (female Anopheles).
Whenever a female anopheles mosquito bites an infected human the parasites enter the mosquito body along with the blood which they are drinking. Actual development and maturing of malaria parasites takes place in the mosquito’s body. Parasite produced in the human body reaches the intestine of the mosquito where they break out the mosquito intestine and then migrate to the salivary glands. After they reach the salivary glands, they wait till the mosquito bites another human, and the process of infection and disease starts again.

Hence, the correct answer is option (A).

Additional information:
Infective stage of malaria i.e. sporozoites grow and multiply in the liver of the human host to become merozoites. Merozoites invade the red blood cells to form trophozoites during which the symptoms of malaria appear.

Note: In malaria, parasites transmitted by the anopheles enter into the bloodstream and then in the liver where they invade the hepatocyte and within these parasites grow and feed. Mosquito saliva contains numerous proteins which facilitates blood-feeding and influences pathogen transmission.