Massive hemolysis, blackwater fever, and central nervous system involvement are most common with which species?

The correct answer is associated with Plasmodium falciparum, which is known for causing severe cases of malaria. This species is capable of leading to massive hemolysis, where there is extensive breakdown of red blood cells. This process can result in hemoglobinuria, which is often referred to as "blackwater fever," characterized by dark-colored urine due to the presence of hemoglobin released from lysed red blood cells.

Furthermore, Plasmodium falciparum is notorious for its capacity to invade the central nervous system, leading to cerebral malaria. This severe manifestation is due to the sequestration of parasitized red blood cells in the cerebral microvasculature, causing considerable neurological complications.

In contrast, other species have different clinical presentations. Plasmodium vivax and Plasmodium ovale tend to lead to relapsing malaria due to their ability to form hypnozoites in the liver but do not typically cause severe hemolysis or cerebral malaria. Plasmodium malariae often causes a milder and more chronic form of malaria, generally not associated with the severe complications highlighted in the question. These distinct characteristics make Plasmodium falciparum the correct choice for the severe symptoms described.