Answer: P. falciparum with early trophozoites (ring forms) and schizonts. Also shown (last photo) is a monocyte with malaria pigment (hemozoin). Although the differential diagnosis includes infection with 2 different Plasmodium species (notably with P. falciparum and P. malariae), the relatively high percent parasitemia and characteristics of the schizonts are most suggestive of a single infection with P. falciparum.
Marco Ligozzi mentions that "P. falciparum schizonts are rarely seen in the peripheral blood and their presence may indicate a potentially severe malaria." Similarly, Anonymous notes that "Urgent treatment is needed!"
Given the risk for severe, potentially overwhelming infection with P. falciparum, it is important to notify the clinical team immediately and explain the implication of finding P. falciparum schizonts in the peripheral blood. Fortunately this patient was treated immediately and responded well to treatment.