Plasmodium Life Cycle: Diagram, Causes, Symptoms, Treatment

Plasmodium Life Cycle: Plasmodium is a genus of parasitic protozoans that fall under the class Aconoidasida, the sporozoan subclass Coccidia, and the family Apicomplexa. Plasmodium infects red blood cells in mammals, e.g., humans, birds, and reptiles. A plasmodium species called P. knowlesi causes Malaria. Malaria develops when an infected female Anopheles mosquito bites a human or any other mammal. Other Plasmodium species known to spread malaria include P. vivax, P. ovale, P. malariae, and P. knowlesi. The plasmodium parasite has a complicated life cycle because it uses an insect (mosquito) to carry and spread the disease.

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This Story also Contains

1. Understanding Plasmodium
2. Hosts in Plasmodium Life Cycle
3. Life Cycle of Plasmodium:
4. Stages of Plasmodium Life Cycle
5. Transmission to Mosquitoes
6. Plasmodium Life Cycle Diagram
7. Life Cycle of Plasmodium: Key Stages, Location, and Duration
8. Symptoms of Malaria
9. Diagnosis and Treatment:
10. Prevention and Control of Malaria

Malaria is still prevalent in many parts of the world and continues to be a cause of death for millions of people each year. It is more common in tropical and subtropical areas of the world, especially Sub-Saharan Africa, Asia and Latin America. Let’s look at the life cycle of a plasmodium to get a better understanding.

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Understanding Plasmodium

Genus Overview: The Plasmodium species is not scarce and most of it affects reptiles, birds and mammals. The species infecting humans are mainly familiar with malaria.

Morphological Features: There are hypothetical stages of the parasite; sporozoites, merozoites, trophozoites and gametocytes. These stages also exhibit specific distinctive features, particularly the shape, size and ability to be stained.

Species Differences:

P. falciparum: It causes severe malaria, multiplies faster, and has complications most of the time.

P. vivax: P: falciparum malaria, responsible for relapses because of latency in the liver stages known as hypnozoites.

P. ovale: Unlike P. vivax, but less frequently.

P. malariae: Can cause chronic infections with the likelihood of later effects.

P. knowlesi: An emerging zoonotic species of macaque that becomes a severe human malaria agent in some cases.

Hosts in Plasmodium Life Cycle

Plasmodium requires two hosts to complete its life cycle: human beings, which act as the intermediate host, and female anopheles mosquitoes, which act as the definitive host.

Human Host:

Asexual Reproduction: It occurs in the human liver and erythrocytes, or red blood cells (RBCs).

Mosquito Host:

Sexual Reproduction: It occurs in the gut of female anopheles whose eggs are laid in water. This step is important for the transmission of malaria from the man vector to other men or the next generation of man vectors.

Role of Anopheles Mosquito: female Anopheles mosquitoes are considered as the primary means of malaria pathogens, plasmodium parasites are transferred in the intimacy of a blood meal.

Life Cycle of Plasmodium:

The life cycle of a plasmodium is divided into different stages to better understand the process at each step.

Stages of Plasmodium Life Cycle

Infection in Humans

1. Sporozoite Stage:

Transmission: Sporozoites are in fleas, and they get to people through the sting of the infected smears.

2. Liver Stage (Exo-erythrocytic Cycle):

Entry: Sporozoites penetrate hepatocytes (hepatitis cells). Asexual reproduction begins in hepatocytes. After getting into the hepatocytes, the sporozoites multiply asexually. Some of the hepatocytes are destroyed and replaced by new cells., thus transforming into new forms through asexual reproduction. Kinetoplastids are protozoa that multiply after entering the hepatocytes.

Asexual Reproduction: Schizonts are formed in the cells of the liver, and the parasites also multiply here.

Release: Schizonts then rupture, and the released forms, known as merozoites, are released into the bloodstream.

3. Blood Stage (Erythrocytic Cycle):

Invasion: Merozoites invade RBCs.

Trophozoite Formation: They then form ring-shaped trophozoites inside the RBCs.

Schizont Formation: The blobs called trophozoites multiply and differentiate into schizonts, which in turn rupture RBCs to liberate more merozoites.

Symptoms: Cycle of rupture and destruction of RBCs results in clinical manifestations of malaria like fever, chills and anaemia.

Transmission to Mosquitoes

Gametocyte Stage:

Formation: Both male and female gametocytes are produced in the bloodstream of human beings.

Maturation: Gametocytes get enlarged and are in a position to be taken inside the digestive tube of the mosquito.

Mosquito Stage (Sexual Reproduction in Mosquitoes): Mosquito Stage (Fertilisation and Laying Their Eggs in Water):

Ingestion: From the studies, it has been noted that female Anopheles mosquitoes that are fed with blood are infected by gametocytes.

Fertilisation: Inside the body of a mosquito, the two male and female gametocytes fertilise to form a zygote called ookinete.

Oocyst Formation: It penetrates through the gut wall and forms an oocyst in it.

Sporozoite Production: Thousands of sporozoites are produced in several sections of the oocyst.

Migration: Sporozoites enter the mosquito's salivary glands and prepare it for transmission.

Plasmodium Life Cycle Diagram

Visualisation of the life cycle of Plasmodium parasite

Life Cycle of Plasmodium: Key Stages, Location, and Duration

Symptoms of Malaria

Symptoms: Malaria is accompanied by subsequent symptoms:

• fever,

• chill,

• headache,

• muscle ache,

• fatigue,

• nausea,

• vomiting,

• diarrhoea

• occasionally anaemia.

P. Falciparum causes severe malaria that develops into complications like

• Cerebral Malaria,

• Severe anaemia,

• Multi-Organ Dysfunction.

Diagnosis and Treatment:

However, malaria is diagnosed through a simple blood test by background lab technicians that doesn’t take much of the time of clinically qualified personnel. Management of malaria consists of antimalarial agents such as chloroquine, artemisinin-based combination therapy (ACT), and others depending on the Plasmodium species as well as the resistance profile of the parasite.

Prevention and Control of Malaria

Mosquito Bite Prevention: Insecticide-treated bed nets, repellents, protective clothes, curtains and ceilings treated with insecticides were used.

Antimalarial Drugs: Travel and endemic malaria preventive uses of antimalarial drugs.

Vaccines: cases of vaccines that can prevent malaria.

Vector Control: They include indoor residual spraying (IRS), Larval source management (LSM), sweeps, and modifications of environmental conditions to eliminate or minimise mosquito breeding.

Conclusion

Knowledge of the life cycle of the Plasmodium parasite is important in the attempt to reduce and possibly eradicate malaria. By preventing, diagnosing, and treating malaria as well as breaking its transmission cycle, the group's global toll of malaria can drastically be cut down.

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