The main difference between Plasmodium and sporozoites is that Plasmodium is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects, whereas sporozoites is a motile spore-like stage in the life cycle of some parasitic protozoans such as Plasmodium that is typically the infective agent introduced into a host.
Plasmodium and sporozoites are two types of organisms that can cause malaria. Both are microscopic.
Key Areas Covered
1. What is Plasmodium
– Definition, Facts, Life Cycle
2. What are Sporozoites
– Definition, Facts, Importance
3. Similarities Between Plasmodium and Sporozoites
– Outline of Common Features
4. Difference Between Plasmodium and Sporozoites
– Comparison of Key Differences
Key Terms
Plasmodium, Sporozoites
What is Plasmodium
Plasmodium is a genus of parasitic protozoans of vertebrates and insects. Also, it is a unicellular eukaryote. The main significant feature of plasmodium is that a life cycle stage of plasmodium called sporozoites infect humans through a blood meal of Culex or Anopheles mosquito. The injected parasites grow inside the body tissue, often in the liver, and then enter the bloodstream infecting red blood cells. The destruction of red blood cells causes malaria.
Life Cycle – Plasmodium
Plasmodium has distinct life cycle stages that occur inside the mosquito and vertebrate bodies. The male and the female gametocyte stages enter the mosquito from an infected vertebrate host. In the mosquito’s midgut, gametocytes develop into male and female gametes and undergo fertilization. The forming zygotes develop into a motile ookinete form that embeds into the gut’s exterior membrane. Also, ookinete develops into oocytes that divide into many elongated sporozoites. Sporozoites migrate into the mosquito’s salivary glands to inject into the blood of the next host.
Figure 1: Plasmodium Life Cycle
Furthermore, sporozoites infect the liver of the vertebrate and undergo replication—the liver stage of Plasmodium forms merozoites. Merozoites grow into ring-shaped forms and then develop into a large form called trophozoites that mature into schizonts. These schizonts then divide multiple times to form merozoites. However, merozoites infect the red blood cells, differentiating into male and female gametocytes.
What are Sporozoites
Sporozoites are a stage of the life cycle of Plasmodium parasites that cause malaria. Importantly, it occurs in the asexual stage of the life cycle. Also, it develops inside the salivary glands of the mosquito. Additionally, it leaves the mosquito during the blood meal, entering liver cells. Further, they divide inside the liver cells forming and releasing merozoites into the bloodstream. Apart from that, sporozoites are motile, and they move through gliding.
Figure 2: Plasmodium – Sporozoite
Similarities Between Plasmodium and Sporozoites
- Plasmodium and sporozoites are two types of organisms that belong to the phylum Apicomplexa.
- They are microscopic and can cause malaria.
Difference Between Plasmodium and Sporozoites
Definition
Plasmodium is a genus of unicellular eukaryotes and are obligate parasites of vertebrates and insects. At the same time, sporozoites are a motile spore-like stage in the life cycle of some parasitic sporozoans, such as Plasmodium, which is typically the infective agent introduced into a host.
Significance
Plasmodium causes malaria, while sporozoites are the infective stage of Plasmodium.
Structure
The gametocyte of Plasmodium is crescent- or sausage-shaped and is usually about 1.5 times the diameter of an RBC in length. At the same time, sporozoites are an elongated crescent shape and are tailored for lasting continuous locomotion and host cell invasion.
Importance
Plasmodium is a parasitic protozoan, while sporozoites are injected into humans through the blood meal of the Anopheles mosquito.
Conclusion
In brief, Plasmodium and sporozoites are the two protozoans that cause malaria in humans. The gametocyte of the Plasmodium is crescent, and the size of the gametocytes is about 1.5 times the diameter of an RBC. Plasmodium is a parasitic protozoan that causes the disease malaria. Anopheles is the vector for the disease. It injects malaria sporozoites into the bloodstream of humans. Therefore, sporozoites are the infectious stage of malaria disease. Also, it is a motile-spore-like stage. However, the main difference between Plasmodium and sporozoites is their structure and importance.
References:
- Wikimedia Foundation. (2023e, April 1). Plasmodium. Wikipedia.
- Frischknecht F, Matuschewski K. Plasmodium Sporozoite Biology. Cold Spring Harb Perspect Med. 2017 May 1;7(5):a025478. doi: 10.1101/cshperspect.a025478. PMID: 28108531; PMCID: PMC5411682.
Image Courtesy:
- “Life Cycle of the Malaria Parasite.” By National Institutes of Health (NIH) – Own work (Public Domain) via Commons Wikimedia
- “Malaria” By Ute Frevert – Own Work (CC-BY 2.5) via Commons Wikimedia
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