The greatest malaria morbidity and mortality is attributed to which Plasmodium species?

• A. P. falciparum
• B. P. vivax
• C. P. malariae
• D. P. ovale

Answer: (A)

In malaria, the species determine how severe the illness tends to be. The parasite most associated with the highest morbidity and mortality is the one that can reach very high levels in the blood and cause widespread vascular problems. Its infected red blood cells stick to the lining of small blood vessels (a process called sequestration), especially in the brain, which leads to cerebral malaria and can trigger organ failure, severe anemia, metabolic disturbances, and death. This combination of high parasite loads and microvascular obstruction makes this species responsible for the majority of severe and fatal malaria cases, particularly among non-immune travelers and young children in highly endemic areas. Other species—P. vivax, P. malariae, and P. ovale—tend to cause malaria with lower parasite levels and fewer life-threatening complications, though P. vivax can occasionally be severe and relapses due to liver parasites, the overall mortality burden remains much lower than that of the more virulent species.