Trypanosomes are dangerous parasites

Trypanosomes are one of the families of protists - unicellular organisms such as Euglenozoa (euglenozoa).

Trypanosomes belong to pathogenic microorganisms and pose a health hazard, causing severe damage to human systems and organs.

The structure of trypanosome

The structure of trypanosome, that is, its morphological structure, has the form of tripomastigota during the adult, trypanosomal stage of development. The body of the trypanosome, 12 to 40-70 microns in length, has the longitudinal shape of a strongly elongated oval with pointed ends (resembling a spindle).

It consists of a single cell - mitochondria with cytoplasm and a single nucleus; the cell has a dense glycoprotein membrane (periplast). Also in the trypanosome cell there is a discoid organelle, kinetonucleus (or kinetoplast) containing DNA, and a smaller body (kinetosome or blepharoplast), from which the outer cell proliferation of the flapellopodium trypanosome begins. This organoid of movement of a parasite is simply called a flagella. It stretches along the body of the cell and lifts the periplust-formed lamellar membrane, which is also located along the entire cell (on the one hand). Specialists call it the undulating membrane (from the Latin undulatus - undulating), and its function - wriggling, to push the trypanosome in the right direction. Such a structure of trypanosome is inherent in the parasite, when it is in the body of the final host.

In addition, while there, trypanosome can be in the form of amastigota (oval shape, smaller and without flagella). But at the critical stage, staying in the body of an insect-carrier, the morphological structure of the cell acquires the form of epimastigota: the cell is elongated, but the flagellum is short and the undulating membrane is very underdeveloped.

By the way, trypanosome kruzi has a C- or S-shaped body, as well as a longer flagellum and a narrowed undulating membrane.

Life cycle and reproduction of trypanosome

Trypanosomes are obligatory parasites, that is, their existence outside the foreign organism is impossible: the host provides nutrition and a comfortable habitat for the parasite. Therefore, the entire life cycle of the trypanosome passes either in the body of an insect, or in the body of a person (or animal). So the life cycle of this parasite is two-stage.

The main (final) host for trypanosomes, according to most biologists, is a man, and an insect-bloodsucker that carries a parasite has received the status of an intermediate host.

African trypanosome develops in the anterior parts of the intestine of a tsetse fly after it is sucked by the blood of an infected vertebrate. As a result, Trypanosoma brucei or Trypanosoma gambiense trypomastigotii, which begin to multiply and become epimastigotes, are found in her body. Having reached the salivary glands of the insect, epimastigots continue to be intensively divided. The life cycle of trypanosome in the body of a fly takes about three weeks. Directly into the saliva, the parasite penetrates only when it develops to the stage of metacyclic tripomastigoth, which enter the proboscis. Now the bloodthirsty insect remains only to bite the victim of its insatiable appetite, and is ready - mature trypanosomes migrate to the new owner.

First, trypomastigots remain in the skin cells for some time (up to ten days), from there they move to the lymphatic system, and then pass into the blood, adhering to red blood cells and leukocytes. But in the blood they can not reproduce and with blood "travel" throughout the body in search of a suitable "place of residence" - in cerebrospinal fluid, lymph and in various organs. And there begins the reproduction of trypanosome, which leads to the poisoning of the body with metabolites of its vital activity and damage to tissues of internal organs.

Propagation of trypanosome is asexual, carried out by longitudinal binary mitosis, during which the mitochondria and nucleus are divided into two parts - replicating two copies of each chromatid.

The multiple process of division of the American trypanosome (with the formation of an epimastigot) takes place in the intestines of bedbugs. When the parasite cell becomes a tripomastigot, that is, it acquires a metacyclic form, it is ready to change the host. Exit out of the intestine alone - with excrement, which animals lick off from themselves when bitten by an insect and become infected. And people scratch the bitten place, and the infectious feces of the bug fall into the skin cells through the hole from the bite and microscopic damage to the integrity of the skin when combing.

Where dwells and what does trypanosome feed on?

So, where does trypanosome live? The environment of their habitat parasites of trypanosome brucia and trypanosome gambiensse selected blood, lymph, lymph nodes, cerebrospinal fluid (spinal fluid), protein-rich serous fluids, as well as tissues of the spinal cord and brain. American trypanosome in the human body most often settles in cells of lymph nodes and blood vessels, liver and spleen, bone and brain, as well as muscle tissues (including myocardium).

What do trypanosomes eat? What they need to maintain their existence and reproduction - the glycoproteins and carbohydrates of the blood plasma of their host. Holes for ingestion of food inside (cytostoma) in trypanosomatides are not present, therefore they satisfy hunger with the help of endosmosis - absorption of liquid nutrients by the whole cell membrane. It should be noted that trypanosomes refer to anaerobes, that is, they do not need oxygen to get energy and they have a cytochrome respiration system.

The mechanism of adaptation of trypanosomes to the host organism and the way of protection from it is recognized by microbiologists as unique. In order to "mislead" the human or animal immune system, the trypanosome gene is activated, which is engaged in changing the sequence (transcoding peptide bonds) of the amino acids that make up their protein shell. That is, the foreign agents (antigens) of the parasite to which the immune cells of the host organism react, change, and the process of their detection, identification and neutralization is delayed. And at this time trypanosomes have time to breed.

Types of trypanosomes

According to the parasitological systematization, the class of trypanosome is heterotrophic eukaryotic pathogenic endoparasites.

Trypanosome in Latin (borrowing from Greek): class Mastigophora (flagellates, from Greek mastig - flagella), subclass of animal flagellates (Zoomastigina), order Kinetoplastida (kinetoplastida). And according to the classification protist, class of trypanosomes - kinetoplastida, family - trypanosomatides, type - trypanoplasma. Several varieties of this endoparasite cause a very dangerous pathology in humans.

African trypanosome - the cause of development in humans and animals of African trypanosomiasis (sleeping sickness). The disease occurs after the entry into the body of such parasites as trypanosoma brucei (Trypanosoma brucei) and trypanosome gambiens or trypanosoma gambiens (Trypanosoma gambiense). In the first case, physicians define the pathogen as Trypanosoma brucei gambiense (Tbg), which affects the population in the countries of West and Central Africa and causes a chronic infection lasting for months and years. In the second case, the pathogen type has the refined name Trypanosoma brucei rhodesiense (Tbr), and it leads to an acute form of a sleeping sickness (with severe CNS lesions) mainly among the rural population of the eastern and southern part of the African continent.

The method of infecting trypanosomes of these species inoculum is through the bite of a specific insect-bloodsucker. Inhabitant in countless quantities, a tropical tsetse fly is a transporter of brucia trypanosomes and gambiens. The main types of tsetse flies (Glossina) that can infect humans with African trypanosomiasis include G. Palpalis, G. Tachinoides and G. Morsitans.

Trypanosoma cruzi (Trypanosoma cruzi) or American trypanosome is endemic for Central and South America. The result of her invasion of the body is Chagas' disease (named after the Brazilian bacteriologist, Carlos Chagas, who discovered it), accompanied by an inflammation of the heart muscle and the membranes of the brain. The method of contamination with trypanosomes of Krusi inoculum-contaminating: - bite of one of the species of triatomic bedbugs-hematophagous (Triatoma infestans, Rhodnius prolixus, etc.), as well as getting into the combed bite bite of its infected feces. The bug itself becomes infected by biting the walking and flying "depositaries" of the parasite - rodents, armadillos, opossums, bats, etc.

Trypanosoma horse (Trypanosoma eouipedum) causes the so-called horse sickness of horses, since the transmission of trypanosomes of this species occurs during their mating. Often, branzheim trypanosome appears as horse trypanosome, as horses are infected with it in the central regions of Africa, and the developing fatal Nagan (Ngana) disease affects many other domestic animals.

Prevention of trypanosomes

The main prevention of trypanosomes today is to fight their carriers - insects. All available means of protection are used for this: repellents, mosquito nets, screens and traps to prevent tsetse and bug flies from entering residential and public premises, and processing insecticides' habitats for their destruction. And, of course, monitoring the health status of the population in endemic areas - by regularly taking blood tests for Trypanosoma brucei gambiense (Tbg).

Human trypanosomiasis is endemic in 36 countries in sub-Saharan Africa, home to almost 70 million people. According to WHO, which has adopted and is implementing a program to combat sleeping sickness in African countries, an average of 25,000 people get sick every year. And, since it is a disease in the countryside, many patients undergo diagnostics, but do not heal and die in their villages ...

It is now recognized that the most effective prevention of trypanosomes is the clearing of certain areas (especially in places of high humidity) from those species of vegetation that serve as a refuge for flies.

The importance of trypanosome in nature

If protists, which include trypanosomes, are an integral part of the biosystem of our planet, and many of them make a positive contribution to its stabilization (producing oxygen, absorbing bacteria and processing organic residues), then the value of trypanosome in nature - such as malarial plasmodia , dysenteric amoeba or lamblia - difficult to determine.

Scientists regard parasitism as the principle of the existence of certain organisms at the expense of others. If such an existence harms one of its participants, causing dangerous diseases of the host of the parasite - the person, then the idea that 7 billion of the population of the Earth is nothing compared to the number of parasitic microorganisms living on the planet involuntarily suggests itself.

We consider them to be the class of the simplest, and they, having mitochondria and flagella, have adapted to such extreme conditions in which no one would have lived a few minutes.

Of course, the article on trypanosomes is clearly not an excuse for philosophizing, but perhaps the significance of trypanosome in nature is that a person still recognizes himself as part of this nature and begins to behave not as its conqueror or, even more, the king ...