Human protozoan parasites, despite their microscopic size, are one of the most dangerous microorganisms that can cause severe diseases.
General information about representatives of protozoa
The kingdom of Protozoa has a large number of representatives (about 15 thousand species), many of which are human parasites.
Another name for this kingdom, accepted in medicine and biology, is single-celled organisms.
These creatures consist of one cell of a certain shape, some can change it, the cell has organelles that maintain viability.Single-celled microorganisms have adapted to locomotion using cilia, flagella or pseudopods.
Due to their small size and structural features, protozoa can live even in the most protected tissues of the body.Parasites of the protozoan kingdom are causative agents of diseases of varying severity, some of them can even lead to death.
Getting rid of single-celled organisms is complicated by the fact that they are able to become covered with a protective shell (cyst) and wait out conditions unfavorable for their existence.
Classification of the simplest inhabitants of the human body
Single-celled parasites are divided into 4 classes, depending on the structure of the cell and the way of life.
Table “Classes and representatives of protozoan parasites”
| Class | Brief description | Representatives |
| Flagellates | The cells are oval in shape, have a flagellum for movement, move forward with a cord, thus being able to penetrate deeply into the liquid medium.Flagellate colonies can reach 10 thousand individuals.Most species live in tropical and subtropical climates. | Leishmania, Giardia, Trichomonas, Trypanosoma. |
| Sardcodae (rhizopods) | Movements are carried out with the help of pseudopods and have a variable body shape. | Dysenteric amoeba |
| Sporozoans | They got their name due to the presence of a spore stage in their development.Localized in tissues and cells, they can cause hepatitis or anemia. | Piroplasmas, Babesia, Coccidia, Plasmodium falciparum. |
| Ciliates | Move with the help of cilia, can live attached or swim freely | Balantidium |
Depending on the location of localization, single-celled parasites are divided into 2 types:
- endogenous (live in internal organs and systems);
- exogenous (choose the skin as their place of residence).
Human protozoan parasites can move throughout the body and infect various organs and tissues.
What diseases are caused by flagellates and ciliates?
Class Flagellates
- Leishmania causes cutaneous leishmaniasis (Pendinsky ulcer) and visceral leishmaniasis, the first manifests itself as constantly rotting ulcers on the body, and the second causes inflammation and bleeding.Leishmania enters the body through warm-blooded animals or a mosquito bite and affects the skin, heart, kidneys, blood, and bone marrow.
- Giardia, the causative agent of giardiasis, affects the mucous tissues of the intestines or gall bladder.After the defeat, people begin to suffer from asthma, mental disorders (most often depression), and the skin becomes dry.Giardia is common in countries with hot climates.
- Trichomonas (depending on the habitat - oral, intestinal and genital or urogenital), causes trichomoniasis.After infection, a person feels itching in the area of the reproductive system, and pathological discharge from the genitals is observed.The biggest danger of this disease is the high risk of developing infertility.
- Trypanosoma causes African or American trypanosomiasis (the first is sleeping sickness, the second is Chags disease).It affects the lymph nodes (they enlarge), cerebrospinal fluid, blood and spleen, as a result of which the functioning of the spleen and liver is disrupted, the patient suffers from drowsiness and may die.
Ciliate class
Balantidia is the causative agent of balantidiasis, affecting the mucous membrane of the large intestine.A clear sign of this parasite is diarrhea with mucus and blood.This disease often ends in death.
What diseases are caused by rhizomes and sporozoans?
Sporozoan class
- The malarial plasmodium enters the blood and liver and causes malaria.Symptoms of the disease are fever, chills or fever, disorders of the central nervous system, and death is possible.It is transmitted through the bites of malaria mosquitoes and is transmitted by humans.
- The causative agent of toxoplasmosis is toxoplasma, which affects the central nervous system, digestive organs, muscle tissue and eyes.At first it occurs without symptoms, then disturbances in the functioning of certain organs are observed.
Class sardcode
Dysenteric amoeba is the causative agent of amoebiasis, affecting the mucous membrane of the large intestine, and less commonly, the bladder and skin.It may be asymptomatic, or it may signal itself with vomiting, diarrhea mixed with blood, and low-grade fever (up to 37.5 degrees).Symptoms appear 7-10 days after amoebas enter the body.
Less common are extraintestinal forms of the disease, which affect the liver, lungs or other organs.This disease is common in Asian and tropical countries.
Routes of infection
Single-celled parasites enter our body in different ways - through the skin or natural openings in the human body.
There are four main ways (paths) of human infection with a parasitic disease:
- the contact-household route opens in case of unsanitary conditions and non-compliance with the rules of personal hygiene (during handshakes or using household items, bathing in dirty water, cysts enter the human body and begin to develop), trypanosomes and trichomonas are transmitted through this route;
- through products contaminated with parasites (meat, especially wild animals, fish, dairy products), they can be disinfected using heat treatment; an example of a disease transmitted in this way is toxoplasmosis;
- fecal-oral route: parasites leave the body with feces or vomit, then enter water, food, household items, the owner’s hands, and through them into the body of a new carrier (this route of infection is especially common among children: contact with animals, eating unwashed fruit, playing in a dirty sandbox);
- transmissible (malaria) – transmission of protozoan parasites through bites along with the saliva of the carrier.
Much less often, parasites enter the body in the following ways:
- from mother to fetus during pregnancy, this path is called transplacental, as parasites penetrate through the placenta;
- together with contaminated blood (blood transfusion and other medical procedures, injections, including narcotic ones, during intimacy) - blood contact;
- during sexual intercourse - sexual tract.
Prevention of infection
To prevent infection with unicellular organisms, a person must follow a number of simple rules:
- proper heat treatment of fish and meat, milk control;
- You can eat only those products that have passed sanitary inspection;
- washing fruits before eating, and simply dipping them in water is not enough; you need to wash them thoroughly and, if possible, pour boiling water over them;
- avoidance of casual sexual contacts;
- prevention of insect bites (use of special creams, mosquito nets);
- regular medical examinations for suspected infection and for prevention;
- increasing immunity, including through the consumption of garlic, oranges, carrots, green tea, dried fruits, rice porridges;
- basic knowledge of which protozoa parasitize the human body and how they get there.
It’s easy to follow these rules, the main thing is regularity.
Information about groups of parasites, examples where single-celled parasites live, helps to choose priority among the named preventive measures.
With proper prevention, and in case of illness - surgical treatment, parasites will not harm your body.