Plasmodium malariae infects older and more mature RBCs. P. malariae causes quartan fever (72-hour cycle). The incubation period between infection and symptoms ranging from about 27 to 40 days is longer than P. vivax or P. ovale. Anemia is mild to moderate in infection and central nervous system involvement is rare. Proteinuria is common in patients, and in children it may be associated with clinical signs of nephrotic syndrome.
Infection may end with spontaneous recovery or there may be recrudescence or a series of recrudescences over many years. Recrudescence is when parasitemia is rendered low by treatment or immunity and then increases again. These particular patients are left with a latent infection and persisting low-grade parasitemia for many years. There is no relapse from persistent liver stage parasites, but the blood stage parasites persist for long periods and potentially for life.
