Life Cycle of the Malaria Parasite

Malaria is caused by one of the Plasmodium (P.) parasites carried by female Anopheles mosquitoes. It is released into the human bloodstream after a mosquito bite. Six distinct stages of the malaria parasite lifecycle have been identified.

Malaria Parasite Lifecycle

Stage 1: After getting injected into the human bloodstream following a bite from Anopheles mosquito, the parasites in the form of sporozoites invade the liver.  They stay in the liver cells after destroying them.

Stage2: Over a period of 5 to 16 days, depending on the species of the malaria parasite, sporozoites multiply rapidly to create thousands of red blood cell invading parasites called merzoites. Each of the sporozoit infected liver cell creates thousands of merzoites. Some species of the malaria parasite remain dormant for long periods before causing relapses weeks or months later.

Stage 3: The merzoites now leave the liver cells and invade the red blood cells after entering the bloodstream. In the next 1 to 3 days, asexual replications of merzoites take place leading to the sickness and complications of malaria. These symptoms can last for months if not treated. In the following stages of lifecycle of malaria parasite, it is explained how malaria spreads to other persons.

Stage 4: A few of the red blood cells infected with merzoites stop replicating asexually and instead become male or female gametocyte (formations that develop into male or female parasite). These gametocytes start circulating in the bloodstream.

Stage 5: When a mosquito bites an infected person with gametocytes circulating in his blood, it ingests them. They go on to develop into mature sex cells called gamete. Male and female gametes combine to form what is called an oocyst.

Stage 6: In the last stage of the malaria parasite lifecycle, each of these oocysts forms several sporozoites in the body of the mosquito and reach its salivary glands. These sporozoites are again injected into the human blood when the mosquito bites and re-starts the whole cycle.

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