LIFECYCLE OF LIFECYCLE OF MALARIAL PARASITEMALARIAL PARASITE

Soorej Jaiboi KSoorej Jaiboi K

MALARIAMALARIA

MalariaMalaria is a mosquito borne infectious is a mosquito borne infectious disease affecting humans and other disease affecting humans and other

animals caused by parasitic protozoans (a animals caused by parasitic protozoans (a group of single-celled microorganisms) group of single-celled microorganisms)

belonging to the belonging to the Plasmodium typePlasmodium type..

LIFECYCLE LIFECYCLE

In the life cycle of In the life cycle of PlasmodiumPlasmodium, a female , a female AnophelesAnopheles mosquito (the definitive host) mosquito (the definitive host) transmits a motile infective form (called transmits a motile infective form (called the sporozoite) to a vertebrate host such the sporozoite) to a vertebrate host such as a human (the secondary host), thus as a human (the secondary host), thus

acting as a transmission vector. acting as a transmission vector.

The malaria parasite life cycle involves two The malaria parasite life cycle involves two hosts.hosts.

During a blood meal, a malaria-infected female During a blood meal, a malaria-infected female AnophelesAnopheles mosquito inoculates sporozoites mosquito inoculates sporozoites

into the human host .into the human host .

1)Sporozoites infect liver cells.1)Sporozoites infect liver cells.

2)Mature into schizonts. 2)Mature into schizonts.

3) Which rupture and release merozoites. 3) Which rupture and release merozoites.

4) After this initial replication in the liver ,the 4) After this initial replication in the liver ,the parasites undergo asexual multiplication in parasites undergo asexual multiplication in

the erythrocytes .Merozoites infect red blood the erythrocytes .Merozoites infect red blood cells.cells.

5) The ring stage trophozoites mature into 5) The ring stage trophozoites mature into schizonts, which rupture releasing schizonts, which rupture releasing

merozoites. merozoites.

6) Some parasites differentiate into sexual 6) Some parasites differentiate into sexual erythrocytic stages (gametocytes). erythrocytic stages (gametocytes).

7) Blood stage parasites are responsible for the 7) Blood stage parasites are responsible for the clinical manifestations of the disease. clinical manifestations of the disease.

8) The gametocytes, male (microgametocytes) 8) The gametocytes, male (microgametocytes) and female (macrogametocytes), are ingested and female (macrogametocytes), are ingested

by an by an AnophelesAnopheles mosquito during a blood mosquito during a blood meal. meal.

C) The parasites multiplication in the mosquito C) The parasites multiplication in the mosquito is known as the sporogonic cycle.is known as the sporogonic cycle.

9) While in the mosquito's stomach, the 9) While in the mosquito's stomach, the microgametes penetrate the macrogametes microgametes penetrate the macrogametes

generating zygotes. generating zygotes.

10) The zygotes in turn become motile and 10) The zygotes in turn become motile and elongated (ookinetes). elongated (ookinetes).

11) Which invade the midgut wall of the 11) Which invade the midgut wall of the mosquito where they develop into oocysts. mosquito where they develop into oocysts.

12) The oocysts grow, rupture, and release 12) The oocysts grow, rupture, and release sporozoites. sporozoites.

13) Which make their way to the mosquito's 13) Which make their way to the mosquito's salivary glands. Inoculation of the sporozoites salivary glands. Inoculation of the sporozoites into a new human host perpetuates the malaria into a new human host perpetuates the malaria

life cycle. life cycle.

Only female mosquitoes feed on blood,male Only female mosquitoes feed on blood,male mosquitoes feed on plant nectar, and do not mosquitoes feed on plant nectar, and do not

transmit the disease.transmit the disease.

Malaria parasites can also be transmitted by Malaria parasites can also be transmitted by blood transfusions, although this is rare.blood transfusions, although this is rare.