What is the Difference Between Plasmodium Falciparum and Plasmodium Malariae

The main difference between Plasmodium falciparum and Plasmodium malariae is that Plasmodium falciparum causes the most dangerous form of malaria, whereas Plasmodium malariae causes “benign malaria” that is not nearly dangerous as other malaria.

P. falciparum and P. malariae are two types of Plasmodium species that cause the disease malaria, which is an acute febrile illness spread through the bites of the female Anopheles mosquito.

Key Areas Covered

1. What is Plasmodium Falciparum
     – Definition, Features, Importance
2. What is Plasmodium Malariae
     – Definition, Features, Importance
3. Similarities – Plasmodium Falciparum and Plasmodium Malariae
     – Outline of Common Features
4. Difference Between Plasmodium Falciparum and Plasmodium Malariae
     – Comparison of Key Differences

Key Terms

Plasmodium Falciparum, Plasmodium Malariae

What is Plasmodium Falciparum

P. falciparum refers to the deadliest species of Plasmodium that causes malaria in humans. P. falciparum can be identified in tropical and subtropical areas worldwide and especially in Africa. Generally, Plasmodium multiplies rapidly inside the blood cells. This causes severe blood loss or anemia in humans. The parasitic cells can clog inside small blood vessels. When the P. falciparum infection occurs inside the brain, cerebral malaria occurs with complications that are fetal. However, P. falciparum is associated with the development of Burkitt’s lymphoma, a blood cancer.

Figure 1: P. Falciparum

Furthermore, P. falciparum is a unicellular protozoan parasite of the species Plasmodium. It is responsible for 50% of malaria cases. The four stages of the life cycle of a Plasmodium are sporozoite, trophozoite, schizont, and gametocyte. The sporozoite of P. falciparum is spindle-shaped and 10–15 μm long. The ovoid schizont that grows in the liver is 30–70 μm in diameter. Merozoite that becomes trophozoite has a ring-like structure. The trophozoite feeds on hemoglobin.

What is Plasmodium Malariae

P. malariae is another parasitic protozoan that causes “benign malaria” that is not dangerous as malaria caused by P. falciparum. P. malariae is widespread throughout sub-Saharan Africa, on many of the islands of the western Pacific, much of southeast Asia, Indonesia, and in areas of the Amazon Basin of South America. Moreover, P. malariae infects the female Anopheles mosquito as the vector for the transmission of the disease. The prepatent period, the time of the infection of the parasite within the body, is 16 to 59 days. Apart from that, P. malariae causes chronic infections that can last for a lifetime.

Figure 2: P. Malariae

Moreover, the maximum parasite count is low in P. malariae in comparison to other Plasmodium species. This is because of the lower number of merozoite produced per erythrocytic cycle. It also has a longer development cycle of 72 hours.  

Similarities Between Plasmodium Falciparum and Plasmodium Malariae

• P. falciparum and P. malariae are two species of the genus Plasmodium.
• Plasmodium is a unicellular, obligate parasite of vertebrates.
• In the life cycle of Plasmodium, a blood-feeding insect host injects into the vertebrate host. Then, they grow in the liver and enter into the bloodstream infecting red blood cells. The destruction of red blood cells causes malaria.

Difference Between Plasmodium Falciparum and Plasmodium Malariae

Definition

P. falciparum refers to a unicellular protozoan parasite of humans and the deadliest species of Plasmodium that causes malaria in humans, while P. malariae refers to a parasitic protozoan that causes malaria in humans.

Type of Malaria

P. falciparum is the deadliest species that causes malaria in humans, while P. malariae causes “benign malaria” that is not nearly dangerous as other malaria.

Occurrence

Moreover, P. falciparum occurs in Africa, while P. malariae occurs in sub-Saharan Africa, on many of the islands of the western Pacific, much of southeast Asia, Indonesia, and in areas of the Amazon Basin of South America.

Age of Erythrocyte Preferred

P. falciparum prefers young erythrocytes, while P. malariae prefers old erythrocytes.

Number of Parasites per mm³ of Blood

P. falciparum contains 20-40,000 parasites mm^-3 of blood, while P. malariae contains 5-10,000 parasites mm^-3 of blood.

Development Cycle

In addition, P. falciparum has a shorter development cycle of 48 hours, whereas P. malariae has a longer development cycle of 72 hours.

Trophozoite

P. falciparum contains highly ameboid forms of trophozoites with predominant vacuoles, while P. malariae contains slightly ameboid, band-like forms of trophozoites with inconspicuous vacuoles.

Schizont

P. falciparum contains schizonts larger than red blood cells, while P. malariae contains schizonts slightly smaller than normal red blood cells.

Infected Red Blood Cells

Furthermore, P. falciparum-infected red blood cells become enlarged and frequently distorted, but P. malariae-infected red blood cells do not enlarge.

Haematin

P. falciparum causes light brown haematin in fine granules while P. malariae causes dark brown haemitin in coarse granules.

Fever Manifestation

The fever manifestation is high in P. falciparum, while the fever manifestation is moderate in P. malariae.

Conclusion

In brief, P. falciparum and P. malariae are two species of Plasmodium parasites that cause malaria. P. falciparum is the deadliest species of malaria in humans. It occurs in Africa. P. malariae is less dangerous than P. falciparum, and it causes benign malaria. However, P. malariae mainly occurs in sub-Saharan Africa, on many of the islands of the western Pacific, much of southeast Asia, Indonesia, and in areas of the Amazon Basin of South America. Therefore, the main difference between plasmodium falciparum and plasmodium malariae is the type of malaria they cause.

References:

1. Zekar L, Sharman T. “Plasmodium Falciparum Malaria.” In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.
2. “Plasmodium malariae.” Scientists Against Malaria. 

Image Courtesy:

1. “Plasmodium falciparum 01” By CDC – Own work (Public Domain) via Commons Wikimedia
2. “Mature Plasmodium malariae schizont PHIL 2715 lores” By CDC – Own Work (Public Domain) via Commons Wikimedia