Plasmodium malariae is a parasitic protozoa that causes malaria in humans and animals. It is closely related to Plasmodium falciparum and Plasmodium vivax which are responsible for most malarial infection. While found worldwide, it is a so-called "benign malaria" and is not nearly as dangerous as that produced by P. falciparum or P. vivax. P. malariae causes fevers that recur at approximately three-day intervals (a quartan fever), longer than the two-day (tertian) intervals of the other malarial parasites.
Due to a similarity in the appearances of the pathogens, P. knowlesi infections are often misdiagnosed as P. malariae infections. Molecular analysis is usually required for an accurate diagnosis .
At the schizont stage, after schizogonic division, there are roughly 6-8 parasite cells in the erythrocyte.
Microscopically, the parasitised red blood cell (erythrocyte) is never enlarged and may even appear smaller than that of normal red blood cells. The cytoplasm is not decolorized and no dots are visible on the cell surface. The food vacuole is small and the parasite is compact. Cells seldom host more than one parasite. Band forms, where the parasite forms a thick band across the width of the infected cell, are characteristic of this species (and some would say is diagnostic). Large grains of malarial pigment are often seen in these parasites: more so than any other Plasmodium species. 8 merozoites