Definition of Plasmodium

Plasmodium: The genus of the class of Sporazoa that includes the parasite that causes malaria. Plasmodium is a type of protozoa, a single-celled organism that is able to divide only within a host cell. The main types of Plasmodium are P. falciparum, the species that causes falciparum malaria, the most dangerous type of malaria; P. malariae, the species that causes quartan malaria; P. ovale, a species found primarily in east and central Africa that causes ovale malaria; and P. vivax, the species that causes vivax malaria, which tends to be milder than falciparum malaria.