One of the major sections of protozoology is devoted 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 ways and causes of diseases, their symptoms (one of the individual signs, the frequent manifestation of a disease, pathological condition or disturbance of any life process) and methods of treatment, protozoa occupy a leading position. They are followed by helminthology aimed at getting rid of helminthic invasions and arachnoentomology - systemic methods in medicine that eliminate parasites of arthropods.
The animal world is represented in abundance by single-celled microorganisms that live everywhere, from the seabed to the upper atmosphere. All belong to the sub-kingdom of the protozoa, or protozoa, which has more than 15 thousand representatives of unicellular creatures.
Among the free-living single-celled 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 living 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 life process) amoebiasis. 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 the 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 the cytoplasm. It is lined with a cytoplasmic membrane containing organelles: the endoplasmic reticulum, ribosomes, Golgi apparatus and mitochondria. All of them provide the processes of nutrition, respiration, movement, metabolic processes and excretion.
The body of a single-celled organism has both a constant and a changing shape (it 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 some have an asymmetrical body shape. Representatives of flagellated parasites in appearance resemble a spindle. The rhizomes of the shape (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, fertilization occurs sexually with the formation of a zygote. Almost all simpler organisms are heterotrophic, but among them are autotrophic species of unicellular parasites.
The motor function is produced in the amoeba due to the pseudopodia, it seems to overflow, expelling the pseudopodia. Ciliates move due to the often shortened lashes that 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 pseudopods, wrapping food with pseudopods and absorbing it. Some forms feed using a cellular mouth. Digestion is carried out by phagocytosis - an internal process, as well as pinocytosis - the process of external absorption of food by the entire surface of the body.
The main feature of protozoa at the onset of adverse conditions is the formation of cysts. Particularly characteristic is the process of formation of cysts for the dysenteric amoeba. It allows the parasite (\ one of the types of coexistence 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 single-celled 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 them) are assigned to four main classes:
Sarcode class
The sarcode class includes one of the most common, dangerous to humans, single-celled parasite - the 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 freshly passed stool confirms a disappointing diagnosis, the symptoms of which speak for themselves.
- Tissue, or pathogenic form of the parasite, which leads a parasitic lifestyle in the lumen of the colon. The defeat of the amoeba of the intestinal mucosa is produced specifically.
- Translucent, or the main form of the dysenteric amoeba that lives in the lumen of the large intestine. This form causes symptoms characteristic for this disease. They are observed in the patient's remission process or in the transport phase. The presence of the parasite has not been ascertained in the faeces of any nature.
- The precystic form of the amoeba is fixed in the semi-formed stool 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 acute pains in the lower abdomen, frequent bowel movements of brown stool due to the blood content and streaks of mucus. Body temperature remains within normal limits. A similar picture can periodically accompany the patient for several years and leads to exhaustion, as well as to the development of anemia. With complications caused by the tissue shape of the amoeba and without proper treatment, the patient can die.
Class flagellated or flagellated
A feature is the equipping of the body with the simplest organs of movement - one or more flagella. The 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 of the vaginal form;
- Giardia is a protozoan that causes giardiasis.
class of sporozoa
Typical representatives of sporozoa are malarial plasmodium, which causes symptoms of valaria and toxoplasma, causing noxoplasmosis.
ciliate class
For microorganisms of this class, a feature is the presence of cilia throughout the body of the microorganism. They perform a motor function, thanks to which ciliates have the ability to move quickly. The representative of the class is balantidia, the largest human parasite of the protozoan family. It provokes a severe and severe disease balantidiasis against the background of the ulcerative process. The disease proceeds in an acute subclinical form and can be fatal.