One of the major sections of protozoology is devoted to unicellular microorganisms and considers the unicellular human parasite to be one of the modes 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 disruption of a life process) and methods of treatment, protozoa occupy a leading position. This is followed by helminthology, aimed at eliminating helminthic invasions, and arachnoentomology - systemic methods in medicine that eliminate arthropod parasites.
Wildlife is represented in abundance by single-celled microorganisms that live everywhere - from the sea floor to the upper atmosphere. They all belong to the subkingdom of protozoa, or protozoa, which has more than 15 thousand representatives of unicellular creatures.
Among the free-living unicellular species there are parasitic forms, which are classified as a separate category and cause a number of serious diseases - protozoonoses and the corresponding symptoms, says a senior researcher at the medical center.
The simplest have several dozen types of parasites that live at the expense of the human body. Amoebas are localized in the intestinal tract and cause symptoms (one of the individual signs, a common manifestation of a disease, pathological condition or disruption of a vital process) amoebiasis. If this is a dysenteric form of the parasite, then it provokes the development of dysentery, as well as giardia, which causes giardiasis. The soft tissues of the internal organs can be attacked by Plasmodium and Toxoplasma, leading to unpleasant symptoms of toxoplasmosis and requiring special treatment.
The structure of unicellular organisms
The body of a microorganism is just a cell that includes the nucleus and cytoplasm. It is lined with a cytoplasmic membrane that contains organelles - the endoplasmic reticulum, ribosomes, the Golgi apparatus, and mitochondria. They all take care of the processes of nutrition, respiration, movement, metabolic processes and excretion.
The body of a unicellular 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, others have an asymmetrical body shape. Representatives of flagellated parasites resemble a spindle in appearance. The rhizomes of the form (it can mean: the form 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.
Cells divide by simple mitosis, but in some species fertilization occurs sexually in the reproductive process with the formation of a zygote. Almost all of the simplest organisms are heterotrophs, but among them there are autotrophic species of unicellular parasites.
Motor function is generated in the amoeba due to the pseudopodia, it seems to overflow and eject pseudopodia. Ciliates move because of the often shortening cilia that cover their bodies 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 pseudopodia, with food being encased and absorbed with pseudopodia. Some forms feed with a cellular mouth. Digestion occurs by phagocytosis - an internal process - as well as pinocytosis - the process of external absorption of food throughout the body surface.
The main feature of protozoa at the onset of unfavorable conditions is the formation of cysts. The process of cyst formation in dysentery moeba is particularly characteristic. It allows the parasite (one of the types of coexistence of organisms) to maintain its vital abilities 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 number of properties that distinguish it from inanimate matter, including metabolism, self-preservation 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 unicellular parasites dangerous to humans - the dysenteric amoeba, which exists in the form of 4 different forms:
- The vegetative form is the largest, reaching 20 microns in size. The finding of a parasite in the freshly passed stool 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 large intestine. The defeat of the amoeba of the intestinal mucosa is produced in a specific way.
- Translucent, or the main form of dysenteric amoeba, living in the lumen of the large intestine. This form causes characteristic symptoms for this disease. They are observed in the course of the patient's remission or at the stage of promotion. The presence of the parasite was not detected in the stools of any kind.
- The precystic form of the amoeba is fixed in the semi-formed feces of a human carrier of the disease or in a patient at the stage of recovery.
The main symptoms of diseases caused by amoebic forms are manifested by constant severe pain 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 picture can periodically accompany the patient for several years, leading 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 can die.
Class Flagellates or Flagellates
A characteristic feature is the equipment of the body with the simplest organs of movement - one or more flagella. Pathogenic widespread microorganisms of this class are:
- trypanosomes that cause African sleeping sickness;
- Leshmania, causing urban or rural leishmaniasis;
- trichomonas - causative agent of trichomoniasis, mainly the vaginal form;
- Giardia is a protozoan that causes giardiasis.
Class of Sporozoa
Typical representatives of the sporozoa are malaria Plasmodium, which causes valaria symptoms, and Toxoplasma, which causes noxoplasmosis.
ciliates 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 ciliates can move quickly. The representative of the class is Balantidia - the largest human parasite from the family of protozoa. Causes a serious and serious disease balantidiasis against the background of the ulcerative process. The disease proceeds in an acute subclinical form and can be fatal.