Malaria is a mosquito-born disease of humans caused by protist Plasmodium known as malarial parasite. It is widespread in tropical and subtropical regions, including much of sub-saharan Africa, Asia and the America.Te disease results from the multiplication of malaria parasites within red blood cells, causing symptoms tat typically include fever and headache, in severe cases progressing to coma, and death.
Four species of plasmodium can infect and be transmitted by humans. Severe disease is largely caused by Plasmodium falciparum. Malaria is also caused by Plasmodium vivax, Plasmodium ovale and Plasmodium malariae.
How is Malarial Parasite transmitted?
Te life cycle of the malarial parasite (Plasmodium) is complicated and involves two hosts, humans and females Anopheles mosquito. The disease is transmitted to humans when an infected Anopheles mosquito bites a person and injects the malarial parasites (sporozites) into the blood.
Life cycle of Malarial parasite in Anopheles mosquito:
Mosquitoes first ingest malarial parasite while feeding on an infected human. Once ingested, the gametocytes get differentiated into males or female gametes and fuse in the mosquito’s gut. This produces an ookinete that penetrates the gut lining and produces oocyst in the gut wall. When the oocyst ruptures, it releases sporozoites tat migrate to salivary glands. The sporozoites are injected into the skin, when the mosquito bites a normal person.
Only female mosquitoes fees on blood while male mosquitoes feed on plant sap, thus males do not spread the disease.
The life cycle of malarial parasite in the human body:
Malaria develops via two phases: an pre-erythrocytic and an erythrocytic phase. The erythrocytic pase involves the infection of liver. Te erythrocytic phase involve infections of erythrocytes, or red blood cells.
When mosquito bites a person, sporozoites enter the blood stream, and migrate to the liver. They infect liver cells (hepatocytes), where they multiply into merozoites . They rupture the liver cells, and escape into the bloodstream. Then, merozoites infect red blood cells, were they develop into ring forms, tropozoites and then schizonts which in turn produce futher merozoites.
within the erythrocyte, the parasite multiply asexually, periodically breaking out of their hosts to invade fresh red blood cells. Several such amplification cycles occur. Thus, classical descriptions of waves of fever arise from simultaneous waves of merozoites escaping and infecting red blood cells.
Stages in the life cycle of Plasmodium