Plasmodium Falciparum: What Causes, Pathogen And Diseases

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Plasmodium Falciparum: What Causes, Pathogen And Diseases
Plasmodium Falciparum: What Causes, Pathogen And Diseases

Video: Plasmodium Falciparum: What Causes, Pathogen And Diseases

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Video: Malaria - causes, symptoms, diagnosis, treatment, pathology 2023, February

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  • Main characteristics of Plasmodium Falciparum
  • Plasmodium Falciparum life cycle
  • Role of the main and intermediate host in cycles
  • Plasmodium Falciparum structure
  • Blood for malaria plasmodium
  • Prevention of malaria plasmodia
  • Traditional treatment
  • Interesting Facts
  • You can defeat parasites!

Plasmodium malaria is a single-celled animal of the genus Anopheles that parasitizes humans. Parasitic activity results in a disease called malaria. It manifests itself only where the carrier of the plozmodium, the Plasmodium Falciparum mosquito, lives. For this property, it was called so - malarial.

Plasmodium falciparum
Plasmodium falciparum

What to do in such a situation? To get started, we recommend reading this article. This article details the methods of dealing with parasites. We also recommend contacting a specialist. Read the article >>>

Main characteristics of Plasmodium Falciparum

Plasmodium malaria belongs to the type of sporozoa of the protozoa subkingdom, the order of Haemosporidia, the genus Plasmodium. There are many representatives of this genus in nature, but only 5 types of microorganisms cause malaria: Plasmodium vivax, Plasmodium malariae, Plasmodium falciparum and Plasmodium ovale and Plasmodium ovale. The latter species is considered rare, but also the most dangerous. They can be infected in the tropical zone of Africa and Asia.

All malaria pathogens belong to eukaryotes, that is, organisms that have a nucleus in which hereditary information is stored like in a safe. However, this group of organisms differs from all eukaryotes in that it has several nuclei in one cell at once.

All types of the listed plasmodia have a very complex life cycle, which combines sexual and asexual reproduction with various transformations and effects on the host organism.

This suggests that the evolution of the malaria plasmodium as a parasitic organism has a long period. This is evidenced by the presence of 2 hosts, the change of which in the life cycle of the parasite is mandatory.

Main characteristics of Plasmodium Falciparum
Main characteristics of Plasmodium Falciparum

Plasmodium Falciparum life cycle

Parasites only at first glance seem to be plastic organisms. In fact, their life is subject to very strict rules, deviation from which is fraught with death for the individual.

A distinctive feature is the fact that the developmental cycle of the malarial plasmodium is functionally divided into 2 parts. One of them passes in the body of a mosquito, the other in a person.

In order for the plasmodium to be able to realize its entire hereditary program, it must go through the following stages of development.

  1. Infection of a person begins from the moment he is bitten by an infected mosquito. While the female mosquito is drinking blood, plasmodium in the form of actively floating sporozoite enters the bloodstream along with saliva.
  2. In the blood, it penetrates into the erythrocyte, while increasing in size. Such a transformation gives rise to a new state of plasmodium, which is called the schizont. This developmental stage is necessary in order to carry out asexual reproduction. The active division of schizonts in erythrocytes makes it possible to create many small cells from one large cell, which are called merozoites. In this case, the erythrocyte is completely destroyed, and parasites and toxins enter the blood plasma.

This is where the latent stage of the disease ends in a person and the manifestation of the first symptoms begins.

The next stage in the life cycle of the causative agent of malaria can be called the complete seizure of enemy territory, if by that we mean all the human erythrocytes. The merozoites, carried by the blood stream, penetrate into the erythrocytes that have not yet been destroyed. This is how the next cycle of development of the plasmodium begins, which still manifests itself in asexual reproduction. Stage 2 of the destruction of erythrocytes and a new release of merozoites into the blood plasma gives rise to another attack of fever with all the characteristic signs.

At the stage of re-emergence from erythrocytes, some of the merozoites acquire signs of reproductive cells, that is, male and female cells. In order for the next stage of development in the form of sexual reproduction to occur, plasmodia need to get into the body of a mosquito.

If they are lucky, and the mosquito drinks blood with such cells, then in its body the malaria plasmodium finally matures and turns into gametes. It is in the body of a mosquito that these gametes are fertilized to form an egg. For further development, the egg must penetrate into the mosquito's intestinal wall. There, it transforms first into an oocyst, and then into sporoblasts and, ultimately, into sporozoites. It is they who complete the life cycle, since at this stage the malarial plasmodium returns to the state in which the sporozoites must again enter the human body through the salivary glands.

The stages of development of Plasmodium combined into a single whole 2 such different species - humans and mosquitoes. The question remains: who is the main link for the malaria causative agent?

Plasmodium Falciparum life cycle
Plasmodium Falciparum life cycle

Role of the main and intermediate host in cycles

To describe a parasitic life form, 3 concepts are very important: main, intermediate and reservoir host.

The main host for the parasite is the species in which sexual reproduction takes place. Here the female and male individuals mate, resulting in an individual with a different genotype. The final host is also the organism in which the hermaphroditic parasite is located. After all, fertilization still occurs, although the result of this process is the appearance of a clone, and not a genetically new individual.

The intermediate host is an organism in which asexual reproduction takes place. It is needed in order to increase the number of larvae.

The mosquito is the main host of the malaria plasmodium, and the human is the intermediate. This parasite has no reservoir host.

However, the main owner cannot be considered as the main link in the life cycle. Rather, this concept should be interpreted as the environment where the development cycle ends.

Why does malarial plasmodium need a human body, if its main reproduction occurs in the body of a mosquito? What is the general meaning of intermediate hosts?

This is explained by the ecological laws of the formation of a stable state of the population. Usually, the parasite does not seek to kill its host, because then it loses not only a food source, but also a comfortable living environment. There are exceptions to this rule, but they are extremely rare and represent a very narrow specialization of the parasite.

The malaria plasmodium needs humans in order to increase the number of individuals during the non-sexual stage of development. In the body of a mosquito, Plasmodium could not reach such a number. Having one host in the world of parasites increases the risk of extinction. However, too much interdependence of the final and intermediate hosts also increases the degree of risk. The best variant has long been invented by evolution - this is the transition from parasitism to symbiosis. However, in the malaria plasmodium, such a developmental path has not yet been observed.

Plasmodium Falciparum structure

The only way that Plasmodium malaria enters the human body is through a mosquito bite. And out of more than three thousand species of these dipterans that exist in nature, this parasite is transmitted only by the malaria mosquito of the genus Anopheles (Anopheles superpictus). Moreover, this mosquito must necessarily be a female, since it is she who needs blood as a source of proteins for hatching eggs.

At the time of the bite, the mosquito injects saliva into the human skin (so that the blood does not clot), and together with the saliva, the sporozoites of the malaria plasmodium enter the skin. Sporozoite is a reproductive form of only one stage in the life cycle of this protist. The structure of the malaria plasmodium at the sporozoite stage has the form of elongated and slightly curved cells no more than 15 microns in size.

The main host of the malarial plasmodium is the anopheles mosquito, since in its body the plasmodium is engaged in sporogony (sexual reproduction). And man is an intermediate host of malaria plasmodium, since he uses the organism of Homo sapiens for agamogenesis, that is, asexual reproduction. Biologists have found that in unicellular species of the genus Plasmodium, asexual reproduction has a special form of schizogony, when the original cell is divided not into two daughter cells, but into many at once. Thus, the reproduction of the malaria plasmodium is adapted to the mode of its spread - from one host to another.

Plasmodium Falciparum structure
Plasmodium Falciparum structure

Blood for malaria plasmodium

Blood for malaria plasmodium is taken from a finger on the hand in the usual way, and then a blood smear is made on a sterile slide, which is examined under a microscope.

Since the species of malaria plasmodia differ somewhat from each other in their structure, each species has clear diagnostic signs.

Experts include the structure of the malarial plasmodium and the nature of changes in the affected erythrocytes to such signs. As a rule, such red blood cells are enlarged, some change their shape and color, etc.

Prevention of malaria plasmodia

Until now, no one has managed to create a vaccine against malaria, which is why the prevention of malaria plasmodia is so important.

In malaria-endemic areas of the world, the prevention of malaria plasmodia is primarily aimed at killing Anopheles mosquitoes using insecticides.

For individual protection from the bites of malaria mosquitoes, various repellents (liquid, in the form of creams and aerosols) are used, closed clothes and mosquito nets are put on, which are also sprayed with repellents.

For example, the antimalarial drug Delagil (Chloroquine, Rezohin) in tablets is taken 0.5 g twice a week, and then 0.5 g once a week. The action of the drug is based on the ability of its active substance - a derivative of 4-aminoquinoline - to inhibit the synthesis of nucleic acids and thereby destroy the cells of the malaria plasmodium.

This remedy is contraindicated in case of impaired renal and liver function, severe heart failure, and decreased hematopoietic function of the bone marrow. It should also not be taken by pregnant women and preschool children. Doctors note that after leaving the malarially dangerous area, the drug must be continued for at least another month.

Who knows what else Alexander the Great would have conquered and what Oliver Cromwell would have done for England if they had not been bitten by a malaria mosquito and malaria plasmodium would not have caused a fatal disease.

Prevention of worms in adults
Prevention of worms in adults

Traditional treatment

In medical practice, for the treatment of malaria, etiotropic therapy is used, aimed at localizing and combating the causative agent of the disease. For its effectiveness, preliminary laboratory diagnostics and the correct selection of drugs are important. Depending on the type of plasmodium malaria and the stage of the disease, the patient may be prescribed various antimalarial drugs, as well as a combination of drugs.

Proguanil and Primaquin destroy parasites at the stage of their development in the liver, while Quinine and Atovaquone act similarly in erythrocytes. Chloroquine kills the germ cells of the plasmodium. Bigumal and Primaquine are used to prevent and prevent relapses.

In case of insufficient effectiveness of other drugs, antibiotics are used: Tetracycline and Doxycycline. Depending on the presence of other pathologies and complications against the background of malaria, Furosemide, Clemastine, Mannitol, etc. can also be used. In the tropical form of malaria, a combination of Pyrimethamine and Dapsone is used.

In combination with the main, etiotropic therapy, detoxification measures are also used (to quickly remove toxic waste products of parasites from the body) and pathogenetic treatment (to restore immune reactions and functions of individual organs, normalize metabolic processes in the body).

Interesting Facts

According to the researchers, the ancestor of the modern parasite, the malaria plasmodium, existed as an independent protozoan and was capable of photosynthesis. The spread of the infection supposedly began from Central and West Africa about 50,000 years ago. And the first written evidence of "swamp fever" (as malaria was called in antiquity) dates back to 2700 BC.

Genghis Khan, Dante, Lord Byron, Christopher Columbus and many famous personalities died from malaria fever.

The first known anti-malaria drug is the Kingao plant, which contains artemisinin. Artemisinin is now isolated from wormwood and is used to treat the three-day form of malaria.

Another "ancient" remedy for malaria is cinchona bark powder, which the Indians used to treat fevers of any etiology. They also shared with the Europeans the wonderful secret of healing.

Medical research centers in Texas and Washington are jointly testing a new-generation malaria drug. The drug is capable of stopping the development of the disease at any stage of the life cycle of the malaria plasmodium inside the human body. A single dose of a new medication is enough.

Modern species of Plasmodium malaria are capable of mutation and develop over time resistance to certain antimalarial drugs, in particular, to Chloroquine.

The discovery at the end of the 20th century of the "dormant" stage of development of malarial plasmodium in liver cells, the so-called hypnozoite, allowed scientists to explain the facts of relapses of the disease several months and years later in the human body.

Scientists in America and Australia have established the reason for the weak activity of the human immune system in relation to malaria. When cells are infected, the parasite leaves one of the types of its protein, of which there are about 50 species in its genetics! Before the human immune system recognizes and responds to the foreign protein, the parasite has already produced a new species. This evolutionary protection of the protozoan's DNA allows it to safely parasitize in the human body for a long time.

And scientists in England have found that sea inhabitants - trepangs synthesize a protein that blocks the reproduction of the malaria plasmodium. Researchers have tried to "graft" a useful gene of trepangs into mosquitoes - carriers of the disease, but have not yet achieved 100 percent in their experiments.

Scientific institutes in America, England and the Netherlands are actively developing and testing new vaccines against malaria. For money, volunteers are offered to participate in an experiment in which they will be exposed to this infection. The treatment process takes three days. During the entire experiment, the subjects are under the supervision of doctors.

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