Increased bilirubin and increased serum enzymes may be noted and are not specifically associated with the exoerythrocytic stage. In P. falciparum infection the parasite is identified as a tiny ring form within normal sized erythrocytes. Multiple ring forms are commonly seen in P. falciparum . The gametocytes show a classic boomerang or banana shape. Merozoites usually number between 12-24 per erythrocyte.
Gametocytes are large and circular or ameoboid.
P. malariae may demonstrate band like trophozoites. In P. malariae , the ring forms are rarely multiple and when multiple the possibility of a double infection with another Plasmodium species should be considered. Usually less than 12 merozoites per cell are seen. Decisions regarding treatment of malaria must take into account where the patient will be living while on therapy, the parasite load, the need for natural acquired immunity, patient symptoms, complications, and the problem of drug resistance. Pharmacologic treatment of malaria has become complicated by the emergence of drug resistant forms of parasites.