In malaria, the most favorable time to detect parasites in the peripheral blood is just before which phase?

• A. During the late paroxysmal stage
• B. At the beginning of a paroxysm
• C. The period just following a paroxysm
• D. The period just before a paroxysm

Answer: (D)

In malaria, parasite development inside red blood cells is highly synchronized, so the number of parasites in the bloodstream rises toward the end of a cycle. Just before the schizonts rupture, many red blood cells are occupied by mature parasite stages, making them easier to detect on a blood smear. The rupture period itself triggers the paroxysm (fever), and after rupture, parasites have just released merozoites that invade new cells, which can temporarily reduce the number of intact parasites seen in peripheral blood. Therefore, the best time to detect parasites in the peripheral blood is just before a paroxysm.