What disease is caused by the protozoan Plasmodium?

What disease is caused by the protozoan Plasmodium? The answer is malaria. Malaria is an infectious disease caused by parasites in the genus Plasmodium, most commonly transmitted to people through the bite of an infected female Anopheles mosquito.

After entering the body, the parasite first travels to the liver, where it multiplies. It then infects red blood cells, repeatedly reproducing and destroying them. This blood-stage cycle causes characteristic symptoms such as fever, chills, headache, fatigue, nausea, and anemia. Severe infections can damage the brain, kidneys, liver, or lungs.

Several Plasmodium species infect humans. Plasmodium falciparum causes the most severe disease and the majority of malaria deaths, while Plasmodium vivax is widespread outside much of sub-Saharan Africa. Plasmodium malariae can produce recurring fevers at roughly 72-hour intervals.

Malaria is often confused with mosquito-borne viral diseases such as dengue, yellow fever, and Zika. Those illnesses are caused by viruses, whereas malaria is caused by a protozoan parasite. Diagnosis commonly uses blood-film microscopy or rapid antigen tests.