Question

Anopheles is
A. Endogenous host for Plasmodium
B. Exogenous host for Plasmodium
C. Initial host for Plasmodium
D. Both A and B

Answer 1

Hint:- Anopheles is a genus of mosquitoes that has around 460 species. It was first described by J. W. Meigen. Over 100 species of this genus are associated with transmission of many diseases. Anopheles gambiae is the species associated with malaria transmission in humans.

Complete answer:- Malaria is caused by a unicellular organism of the genus Plasmodium. The female Anopheles mosquitoes spread the disease from man to man. The life cycle of malarial parasites is very complicated. Mosquito is considered as an intermediate host i.e. insect vector.
The life cycle of Plasmodium starts when a mosquito containing sporozoites of the Plasmodium bites a human and injects it in him. The sporozoites then reach the liver of the person through the blood where it reproduces asexually and burst the liver cells and are released into the blood. Parasites then reproduce asexually in the red blood cells and burst the red blood cells causing the cycles of fever and symptoms. The released parasites then infect new red blood cells.
The sexual stages of the parasite called gametocytes develop in the red blood cells. These gametocytes are then taken up by the female Anopheles mosquitoes through their blood meal. Thereafter, fertilization and development of the gametocytes occurs in the mosquito’s intestine and they develop into sporozoites. The mature infective stage i.e. sporozoites escape from the intestine and migrate to the mosquito salivary glands.

Correct option: B. Exogenous host for Plasmodium

Note:- Malaria is a protozoan disease of tropics and temperate areas which spreads by mosquito bites. It is characterized by recurring chills, shivering and rapid rise of body temperature followed by perspiration and gradual fall of temperature, anemia, toxemia and splenomegaly.