Which group of microorganisms cause malaria?

Malaria is caused by protozoa, specifically parasitic protozoans belonging to the genus Plasmodium. Among the several species that infect humans, Plasmodium falciparum, P. vivax, P. ovale, and P. malariae are the most common, with P. falciparum being the deadliest. These single-celled parasites have a complex life cycle involving both human hosts and female Anopheles mosquitoes, which transmit the parasite through blood-feeding.

When an infected mosquito bites a human, Plasmodium parasites enter the bloodstream and travel to the liver, where they multiply before invading red blood cells. This invasion causes the characteristic symptoms of malaria—high fever, chills, sweating, headache, and fatigue occurring in cyclical patterns. Malaria remains a major global health challenge, particularly in tropical and subtropical regions, causing hundreds of thousands of deaths annually despite being preventable through mosquito control measures, bed nets, and treatable with antimalarial medications.