Plasmodium malariae
Overview
Plasmodium malariae is a parasitic protozoa
Protozoa
Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...

 that causes malaria
Malaria
Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

 in humans. It is closely related to Plasmodium falciparum
Plasmodium falciparum
Plasmodium falciparum is a protozoan parasite, one of the species of Plasmodium that cause malaria in humans. It is transmitted by the female Anopheles mosquito. Malaria caused by this species is the most dangerous form of malaria, with the highest rates of complications and mortality...

and Plasmodium vivax
Plasmodium vivax
Plasmodium vivax is a protozoal parasite and a human pathogen. The most frequent and widely distributed cause of recurring malaria, P. vivax is one of the four species of malarial parasite that commonly infect humans. It is less virulent than Plasmodium falciparum, which is the deadliest of the...

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 fever
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...

s that recur at approximately three-day intervals (a quartan fever), longer than the two-day (tertian) intervals of the other malarial parasites, hence its alternate name quartan malaria.
Plasmodium malaria has been recognized since the Greek and Roman civilizations over 2,000 years ago, with different patterns of fever described by the early Greeks.
 
x
OK