**Question:** A 35 year old male suffering from sudden onset of high grade fever. On malarial slide examination, all stages of the parasite are seen with schizonts of 20 microns size with 14-20 merozites per cell and yellow brown pigment. The diagnosis is

A. Plasmodium vivax
B. Plasmodium falciparum
C. Plasmodium ovale
D. Plasmodium malariae

**Correct Answer:** B. Plasmodium falciparum

**Core Concept:** Malaria is a parasitic infection caused by protozoan species belonging to the genus Plasmodium. Symptoms usually include high fever, chills, fatigue, and sometimes anemia and organ dysfunction. Malarial parasites are transmitted to humans through the bite of infected Anopheles mosquitoes. Malarial slides are used to confirm the diagnosis, and the presence of specific parasite stages helps differentiate between species.

**Why the Correct Answer is Right:** Plasmodium falciparum is a severe form of malaria that is characterized by high fever, respiratory distress, and cerebral malaria. In this case, the presence of schizonts (mature forms of the parasite) with 14-20 merozoites per cell and yellow-brown pigment is indicative of P. falciparum infection. This species is known to cause severe malaria and has the highest mortality rate in comparison to other Plasmodium species.

**Why Each Wrong Option is Incorrect:**

A. Plasmodium vivax: This species typically presents with a single peak of fever and has fewer merozoites (8-16) per schizont.
C. Plasmodium ovale: This species can present with a single or multiple peaks of fever and has fewer merozoites (6-8) per schizont.
D. Plasmodium malariae: This species typically presents with a single peak of fever and has fewer merozoites (8-16) per schizont.

**Core Concept:** Malaria is a mosquito-borne disease caused by Plasmodium species, which infects human red blood cells. These parasites undergo asexual reproduction in the host, leading to the formation of merozoites. Malarial slides, including Giemsa-stained blood films, are used to identify the parasite stages, including trophozoites, schizonts, and gametocytes.

**Why the Correct Answer is Right:** Plasmodium falciparum is one of the five species of Plasmodium causing human malaria and is known for causing severe disease manifestations, including cerebral malaria, respiratory distress, and anemia. The presence of schizonts with 14-20 merozoites per cell and the yellow-brown pigment are characteristic features in P. falciparum infection and can help differentiate it from other species.

**Why Each Wrong Option is Incorrect:**

A. Plasmodium vivax: This species typically presents with