Step 1: Understanding the Concept:
Malaria is a life-threatening, mosquito-borne infectious disease spread to humans through the bites of infected female Anopheles mosquitoes. The disease is caused by microscopic protozoan parasites belonging to the genus Plasmodium. Different species of this parasite cause distinct forms of malaria, varying significantly in their clinical presentation, incubation periods, and severity.
Step 2: Detailed Explanation:
Let's analyze the characteristics of the different Plasmodium species listed:
- (A) Plasmodium vivax: Causes benign tertian malaria. While it causes recurrent bouts of fever and chills, it is rarely fatal on its own.
- (B) Plasmodium malariae: Causes quartan malaria, characterized by fever spikes occurring every 72 hours. It typically follows a chronic, mild course.
- (C) Plasmodium ovale: Causes a relatively rare and mild form of tertian malaria, primarily found in West Africa.
- (D) Plasmodium falciparum: This is the most dangerous, virulent, and aggressive species of the parasite. It causes malignant tertian malaria (or simply malignant malaria). It induces severe clinical complications such as the clumping of infected red blood cells, which can clog small blood vessels. This leads to organ failure, cerebral malaria (brain damage), and can be rapidly fatal if not treated immediately.
Therefore, malignant malaria is uniquely caused by Plasmodium falciparum. This matches option (D).
Step 3: Final Answer:
Malignant malaria is caused by Plasmodium falciparum.