One of the great sections of protozoology is dedicated to unicellular microorganisms, and considers human parasitic protozoa as one of the forms of existence of organisms.
From the point of view of medical parasitology, which studies the forms and causes of diseases, their symptoms (one of the individual signs, the frequent manifestation of a disease, pathological condition or disturbance of any vital process) and methods of treatment, protozoa occupy a leading position. They are followed by helminthology aimed at eliminating helminthic invasions and arachnoentomology, systemic methods in medicine that eliminate arthropod parasites.
The animal world is abundantly represented by single-celled microorganisms that live everywhere, from the bottom of the sea to the upper atmosphere. All of them belong to the sub-kingdom of protozoa, or protozoa, which has more than 15 thousand representatives of single-celled creatures.
Among free-living unicellular species, there are parasitic forms classified as a separate category that cause a number of serious diseases - protozoonoses and their corresponding symptoms, says a senior researcher at the medical center.
The simplest have several dozen species of parasites that live at the expense of the human body. Amoebas are localized in the intestinal tract, causing symptoms (one of the individual signs, a frequent manifestation of any disease, pathological condition or disturbance of any vital processes) amebiasis. If this is a dysenteric form of the parasite, it provokes the development of dysentery, as well as Giardia, which causes giardiasis. The soft tissues of internal organs can be affected by Plasmodium and Toxoplasma, causing unpleasant symptoms of toxoplasmosis, which require specific treatment.
The structure of unicellular organisms.
The body of a microorganism is just a cell, which includes the nucleus and cytoplasm. It is lined with a cytoplasmic membrane that contains organelles: the endoplasmic reticulum, ribosomes, the Golgi apparatus, and mitochondria. All of them provide the processes of nutrition, respiration, movement, metabolic processes and excretion.
The body of a unicellular organism has a constant and changing shape (can mean: the shape of an object - the relative position of the boundaries (contours) of the object, the object, as well as the relative position of the points of the line). Some representatives of the protozoa have symmetrical bodies, and others have an asymmetrical body shape. Representatives of flagellate parasites in appearance resemble a spindle. The rhizomes of the form (can mean: the shape of the object, the mutual arrangement of the boundaries (contours) of the object, the object, as well as the relative position of the points of the line) have no body at all.
The cells divide by simple mitosis, but in some species, in the process of reproduction, sexual fertilization occurs with the formation of a zygote. Almost all the simplest organisms are heterotrophs, but among them there are autotrophic species of unicellular parasites.
The motor function is produced in the amoeba by the pseudopods, it seems to overflow, throwing off pseudopods. Ciliates move due to cilia, which are often shortened and which cover their body in abundance. The movement of the flagella is due to the movement of the flagella themselves, from which they got their unpretentious name.
The amoeba feeding process is also associated with the pseudopods, which wrap food around pseudopods and absorb it. Some forms feed using a cellular mouth. Digestion is carried out by phagocytosis, an internal process, as well as by pinocytosis, the process of external absorption of food by the entire surface of the body.
The main characteristic of protozoa in the presence of adverse conditions is the formation of cysts. The process of cyst formation for dysenteric amoeba is especially characteristic. It allows the parasite (\one of the coexisting types of organisms) to maintain its vital capacities during a period of prolonged anabiosis.
The main classes of protozoan parasites (one of the types of coexistence of organisms)
Representatives of unicellular organisms (a living body that has a set of properties that distinguish it from inanimate matter, including metabolism, self-maintenance of its structure and organization, and the ability to reproduce) are assigned to four main classes:
sarcode class
The sarcode class includes one of the most common and dangerous unicellular parasites for humans - dysenteric amoeba, which exists in the form of 4 different forms:
- The vegetative form is the largest, reaching 20 microns in size. Finding a parasite in the freshly passed feces confirms a disappointing diagnosis, the symptoms of which speak for themselves.
- Tissue, or pathogenic form of the parasite, that leads a parasitic lifestyle in the lumen of the colon. The defeat of the amoeba of the intestinal mucosa occurs specifically.
- Translucent, or the main form of the dysenteric amoeba that lives in the lumen of the large intestine. This form causes characteristic symptoms of this disease. They are observed in the process of patient referral or at the stage of transportation. In feces of any nature, the presence of the parasite was not established.
- The precystic form of the amoeba is fixed in the semiformed feces of a human carrier of the disease, or in a recovering patient.
The main symptoms of diseases caused by amoebic forms are manifested by permanent sharp pains in the lower abdomen, frequent bowel movements of brown stools due to blood content, and streaks of mucus. Body temperature remains within normal limits. A similar image can periodically accompany the patient for several years and leads to exhaustion, as well as the development of anemia. With complications caused by the tissue form of the amoeba and without proper treatment, the patient may die.
Class flagellates, or flagellates
A characteristic feature is the equipment of the body with the simplest organs of movement - one or more flagella. Widespread pathogenic microorganisms of this class are:
- trypanosomes, which cause African sleeping sickness;
- leshmania causing urban or rural leishmaniasis;
- trichomonas - causative agents of trichomoniasis, mainly vaginally;
- Giardia is a protozoan that causes giardiasis.
class of sporozoa
Typical representatives of the sporozoa are the malaria plasmodium, which causes symptoms of Valaria, and toxoplasma, which causes noxoplasmosis.
ciliate class
For microorganisms of this class, a characteristic feature is the presence of cilia throughout the body of the microorganism. They perform a motor function, thanks to which the ciliates have the ability to move quickly. The representative of the class is balantidia, the largest human parasite of the family of protozoa. Causes a serious and severe disease balantidiasis on the background of the ulcerative process. The disease proceeds in an acute subclinical form and can be fatal.