マラリア

Malaria is primarily caused by the protozoan parasite Plasmodium, transmitted through the bite of an infected Anopheles mosquito.

When the mosquito bites, it injects sporozoites into the human bloodstream.

These sporozoites travel to the liver, where they invade hepatocytes and divide asexually to form liver schizonts.

Each liver schizont produces numerous merozoites. Once the hepatocytes rupture, the merozoites are released into the bloodstream and begin invading erythrocytes.

Inside the erythrocytes, the merozoites develop into ring-shaped early trophozoites.

As they mature, these trophozoites develop into schizonts within the erythrocytes.

When the schizonts rupture, they lyse the erythrocytes, releasing more merozoites and hemozoin—a byproduct of hemoglobin digestion—into the bloodstream.

Macrophages engulf the merozoites and hemozoin, releasing proinflammatory cytokines, such as TNF-alpha. These cytokines contribute to the characteristic cyclic fever associated with malaria.

Repeated destruction of erythrocytes also leads to anemia and reduced oxygen delivery to tissues.