Main Difference – Plasmodium Falciparum vs Plasmodium Vivax
Plasmodium, a genus of unicellular parasites, causes malaria in animals. It is subdivided into nine subgenera; two or three can be found in mammals, four in birds, and two in lizards. The disease is transmitted by the infected, female Anopheles mosquito. The parasite infects both liver cells and red blood cells of animals. Plasmodium falciparum and Plasmodium vivax are two species of Plasmodium that cause malaria in humans. P. falciparum can be identified in tropical and subtropical areas worldwide and especially in Africa. However, P. vivax can be identified in Latin America, Asia, and some parts of Africa. The main difference between Plasmodium falciparum and Plasmodium vivax is that P. falciparum causes severe malaria as it rapidly multiplies in the blood whereas P. vivax is less virulent than P. falciparum.
Key Areas Covered
1. What is Malaria
– Definition, Symptoms, Plasmodium Life Cycle
2. What is Plasmodium Falciparum
– Definition, Occurrence, Significance
3. What is Plasmodium Vivax
– Definition, Occurrence, Significance
4. What are the Similarities Between Plasmodium Falciparum and Plasmodium Vivax
– Outline of Common Features
5. What is the Difference Between Plasmodium Falciparum and Plasmodium Vivax
– Comparison of Key Differences
Key Terms: Anopheles, Liver Cells, Malaria, Parasite, Plasmodium Falciparum, Plasmodium Vivax, Red Blood Cells
What is Malaria
Malaria refers to a mosquito-borne disease caused by the Malaria parasite Plasmodium. The major symptoms of malaria include fever, chills, tiredness, headaches, and vomiting. Untreated malaria may also cause death. Two types of hosts are infected by the malaria parasite; female Anopheles mosquito and humans. As it carries the disease from an infected human to another, the mosquito is considered as the vector of the disease. Thus, the mosquito is the intermediate host of the parasite. In humans, liver cells are first infected, and then they infect the red blood cells. The growth of the parasite inside the red cells causes the rupture of the cells. The symptoms are caused by the blood-stage parasites. An Anopheles mosquito sucking blood is shown in figure 1.
Figure 1: Anopheles Mosquito
Plasmodium Life Cycle
Plasmodium develops four life stages during its life cycle: sporozoite, trophozoite, schizont, and gametocyte. The mosquito inoculates sporozoites into the bloodstream of humans. Sporozoites are motile and pore-like, and they infect liver cells and develop into schizonts. Matured schizonts contain many merozoites formed by schizogony, a type of multiple fission. The rupture of infected liver cells releases merozoites into the bloodstream, which then infect the red blood cells. Merozoites in red blood cells develop into ring stage trophozoites, which then develop into schizonts or differentiate into gametocytes. Two types of gametocytes are produced: microgametocytes (male gametes) and macrogametocytes (female gametes). These are ingested by the mosquito during the blood meal. The penetration of macrogametocytes by microgametocytes occur inside the stomach of the mosquito, generating the zygote. The elongated zygote that is motile is called ookinetes, and they develop into oocytes inside the mid-gut wall of the mosquito. Oocytes grow and rupture, releasing sporozoites. Sporozoites come to the salivary glands of the mosquito to be inoculated into another human. The life cycle of Plasmodium is shown in figure 2.
Figure 2: Plasmodium Life Cycle
What is Plasmodium Falciparum
Plasmodium 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. P. falciparum in a blood smear is shown in figure 3.
Figure 3: P. falciparum Micro- and Mega-Gametocytes
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.
What is Plasmodium Vivax
Plasmodium vivax refers to the most frequent and widely distributed Plasmodium parasite that causes recurring malaria. P. vivax can be identified in Latin America, Asia, and some parts of Africa. The prevalence of P. vivax is due to the high population density, especially in Asia. P. vivax trophozoites in a blood smear are shown in dark purple in figure 4.
Figure 4: P. vivax Trophozoites
P. vivax consists of dormant liver stages called hypnozoites. The activated hypnozoites invade red blood cells. Since the recurrent invasion of hypnozoites may occur, recurrent malaria or malaria relapses can be identified in humans even after several months or years of a mosquito bite.
Similarities Between Plasmodium Falciparum and Plasmodium Vivax
- falciparum and P. vivax are two types of malaria parasites that belong to the genus Plasmodium.
- Both falciparum and P. vivax are unicellular protozoans.
- Both falciparum and P. vivax are transmitted through the infected, female Anopheles mosquito.
- The asexual phase of both falciparum and P. vivax occurs inside humans, and the sexual phase occurs inside a mosquito.
- The asexual phase of both falciparum and P. vivax is usually 48 days.
- The sexual phase of both falciparum and P. vivax is 10 days at 25-30 °C.
- Both falciparum and P. vivax infect liver cells and red blood cells.
- Both falciparum and P. vivax may cause severe complications in humans.
Difference Between Plasmodium Falciparum and Plasmodium Vivax
Definition
Plasmodium Falciparum: Plasmodium Falciparum refers to the deadliest species of Plasmodium that causes malaria in humans.
Plasmodium Vivax: Plasmodium vivax refers to the most frequent and widely distributed Plasmodium parasite that causes recurring malaria.
Subgenus
Plasmodium Falciparum: P. Falciparum belongs to the subgenus Plasmodium.
Plasmodium Vivax: P. Vivax belongs to the subgenus Laverania.
Occurrence
Plasmodium Falciparum: P. falciparum can be identified in tropical and subtropical areas worldwide and especially in Africa.
Plasmodium Vivax: P. vivax can be identified in Latin America, Asia, and some parts of Africa.
Disease
Plasmodium Falciparum: P. falciparum causes malignant tertian malaria.
Plasmodium Vivax: P. vivax causes benign tertian malaria.
Duration of the Liver Phase
Plasmodium Falciparum: The duration of the liver phase of P. falciparum is 5.5 days.
Plasmodium Vivax: The duration of the liver phase of P. vivax is 8 days.
Number of Merozoites Released from a Liver Cell
Plasmodium Falciparum: Around 30, 000 merozoites are released per infected liver cell.
Plasmodium Vivax: Around 10, 000 merozoites are released per infected liver cell.
Duration of Schizogony
Plasmodium Falciparum: The duration of schizogony is 12 days in P. falciparum.
Plasmodium Vivax: The duration of schizogony is 14 days in P. vivax.
Red Cell Preference
Plasmodium Falciparum: P. falciparum invades younger red blood cells.
Plasmodium Vivax: P. vivax invades reticulocytes and red cells up to 2 weeks long.
Parasitized Red Cells
Plasmodium Falciparum: Parasitized red cells of P. falciparum are not enlarged and contain Maurer’s clefts.
Plasmodium Vivax: Parasitized red cells of P. vivax are enlarged and contain Schuffner’s dots.
Red Blood Cell Color
Plasmodium Falciparum: Red blood cells become black and dark brown.
Plasmodium Vivax: Red blood cells become yellow or golden brown.
Relapses
Plasmodium Falciparum: P. falciparum does not cause relapses.
Plasmodium Vivax: P. vivax cause replaces.
Ring Stage Trophozoite
Plasmodium Falciparum: P. falciparum trophozoite consists of small rings (1/5 diameter of the red blood cells).
Plasmodium Vivax: P. vivax trophozoite consists of large rings (1/3 or ½ diameter of the red blood cells).
Microgametocyte
Plasmodium Falciparum: The microgametocyte of P. falciparum is kidney-shaped with blunt, round ends.
Plasmodium Vivax: The microgametocytes of P. vivax is spherical and compact.
Macrogametocyte
Plasmodium Falciparum: The macrogametocyte of P. falciparum is crescentic.
Plasmodium Vivax: The macrogametocyte of P. vivax is spherical.
Severity of the Disease
Plasmodium Falciparum: P. falciparum causes severe malaria.
Plasmodium Vivax: Malaria caused by P. vivax is less severe.
Conclusion
falciparum and P. vivax are two species of Plasmodium parasite. Both types of parasites are unicellular protozoans that infect both Anopheles mosquito and humans. P. falciparum causes severe malaria while P. vivax causes less severe malaria. Therefore, the main difference between Plasmodium Falciparum and Plasmodium Vivax is the severity of the disease.
Reference:
1.“Malaria.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 1 Mar. 2016, Available here.
2.“Plasmodium falciparum.” Scientists Against Malaria, 9 July 2014, Available here.
3.“Plasmodium vivax.” Scientists Against Malaria, 9 July 2014, Available here.
Image Courtesy:
1. “1016254” (CC0) via Pixabay
2. “Falciparum-life-cycle-final” By Le Roche Lab, UC Riverside – (CC BY 3.0) via Commons Wikimedia
3. “Plasmodium falciparum 01” By CDC/Dr. Mae MelvinTranswiki – the Centers for Disease Control and Prevention’s Public Health Image Library (PHIL) (Public Domain) via Commons Wikimedia
4. “Plasmodium vivax 01” By CDC/ Steven Glenn, Laboratory & Consultation DivisionTranswiki – Centers for Disease Control and Prevention’s Public Health Image Library (PHIL) (Public Domain) via Commons Wikimedia
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