Question

What is the primary and secondary host for the Plasmodium

Answer 1

Plasmodium is an obligate parasite of vertebrates and insects. It is a genus of unicellular eukaryotes. Plasmodium is a parasite causing malaria. Its life cycle includes development in a blood-feeding insect host i.e mosquito. The mosquito then injects plasmodium into a vertebrate host when they bite them.

Complete answer:
-The life cycle of malaria includes infection of humans by the female anopheles mosquito. At first, The parasite ( Plasmodium) grows and multiplies in the liver cells of humans and then transfers to red blood cells. The parasites grow in the red blood cells and release their daughter parasites that are merozoites by destroying them. This cycle is continuous.
The lifecycle of the malaria parasite
-The malarial infection starts when an infected female anopheles mosquito bites a healthy human. Thus, injects the plasmodium parasites in the bloodstream in the form of sporozoites.
-The sporozoites travel quickly into the human liver with the help of the bloodstream and there they asexually divide into the liver cells for 7 to 10 days. In this period no symptoms are produced in the human body.
-After the multiplication of the sporozoites, converted into merozoites and they are released from the liver cells in the vesicles. They travel through the heart and arrive in the lungs where they settle down in the lung capillaries.
-The disintegration of the vesicles allow merozoites to enter the blood phase of their development.
-The merozoites enter the red blood cells in the bloodstream and there they multiply until the cell bursts. Then they start to enter more red blood cells. These repeated cycles of parasites cause fever each time when the parasites break the red blood cells and then invade the blood cells.
-Some blood cells which are infected leave the asexual multiplication cycle and instead of replicating, merozoites develop into the sexual form of the parasite known as gametocytes.
-When again the mosquito bites an infected person the gametocytes enter into the mosquito body, where they further develop into mature sex cells called gametes.
-The female gametes develop into ookinetes and remain in the midgut wall of the mosquito where they form oocysts on the exterior surface.
-Inside the oocyst, many active sporozoites are present. When the oocyst breaks down, a large number of sporozoites are released into the body cavity and they travel to the mosquito's salivary gland.
-This led to the cycle of human infection that starts again when the mosquito bites another person.
-Hence, the primary host is the mosquito, and the secondary host is human.

Note: -Therefore, the parasites which cause malaria develop in both human and female Anopheles mosquitoes.
-The infection by the parasites presents thousands of antigens to the human immune system depending on the size and the genetic complexity of the parasites.
-The individual risk of developing malaria is influenced by both biological and behavioral characteristics.