Despite their microscopic size, human protozoan parasites are among the most dangerous microorganisms that can cause serious diseases.
General information about representatives of protozoa
The kingdom of protozoa has a large number of representatives (about 15,000 species), many of which are human parasites.
Another name for this kingdom accepted in medicine and biology is unicellular organisms.
These living things consist of a 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 pseudopodia.
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 cause death.
The elimination of unicellular organisms is complicated by the fact that they cover themselves with a protective shell (cyst) and can wait for conditions unfavorable for their existence.
Classification of the simplest inhabitants of the human body
Single-celled parasites are divided into 4 classes depending on their cell structure and lifestyle.
Table “Classes and representatives of protozoan parasites”
| Class | Short description | Representative |
| Flagellates | The cells are oval in shape, have a flagellum for movement, move forward with a cord and can therefore penetrate deeply into the liquid medium.Flagellate colonies can reach 10,000 individuals.Most species live in tropical and subtropical climates. | Leishmania, Giardia, Trichomonas, Trypanosoma. |
| Sardcodae (rhizopods) | Movements are carried out with the help of pseudopodia and have a variable body shape. | Dysenteric amoeba |
| Sporozoa | 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. | Piroplasma, Babesia, Coccidia, Plasmodium falciparum. |
| Ciliates | If you move with the help of cilia, you can live attached or swim freely | Balantidium |
Depending on the place of localization, unicellular parasites are divided into two types:
- endogenous (live in internal organs and systems);
- exogenous (choose the skin as a place of residence).
Human protozoan parasites can move through 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 manifesting itself as constantly rotting ulcers on the body and the second causing 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, attacks the mucous tissue of the intestines or gallbladder.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 greatest 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), the cerebrospinal fluid, the blood and the spleen, as a result of which the function of the spleen and liver is disrupted, the patient suffers from drowsiness and may die.
Class of ciliates
Balantidia is the causative agent of balantidiasis and affects 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 sporozoa?
Class of Sporozoa
- The malaria plasmodium enters the blood and liver and causes malaria.Symptoms of the disease include fever, chills or fever, central nervous system disorders, 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 has no symptoms, then functional disorders of certain organs are observed.
Class sard code
Dysentery amoeba is the causative agent of amebiasis and affects the mucous membrane of the large intestine and, more rarely, the bladder and skin.It can be asymptomatic or manifest itself as vomiting, bloody diarrhea and low-grade fever (up to 37.5 degrees).Symptoms appear 7-10 days after the amoebas enter the body.
Extraintestinal forms of the disease that affect the liver, lungs or other organs are rarer.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 routes (pathways) of human infection with a parasitic disease:
- the contact-household route opens in unsanitary conditions and non-compliance with the rules of personal hygiene (when shaking hands or using household items, when bathing in dirty water, cysts enter the human body and begin to develop), trypanosomes and trichomonas are transmitted through this route;
- products contaminated with parasites (meat, especially wild animals, fish, dairy products) can be disinfected by 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 in children: contact with animals, eating unwashed fruits, playing in a dirty sandbox);
- Transmissible (Malaria) – Transmission of protozoan parasites through bites along with the carrier's saliva.
Much less often, parasites enter the body in the following ways:
- From mother to fetus during pregnancy, this route is called transplacental because parasites penetrate through the placenta.
- together with contaminated blood (blood transfusions and other medical procedures, injections, including anesthetics, during intimacy) – blood contact;
- during sexual intercourse - sexual tract.
Infection prevention
To prevent infection with single-celled organisms, a person must follow a number of simple rules:
- proper heat treatment of fish and meat, milk control;
- You can only eat products that have passed hygiene control;
- It is not enough to wash the fruit before eating and simply immerse it in water.You need to wash them thoroughly and, if possible, pour boiling water over them;
- avoiding casual sexual contact;
- Prevention of insect bites (use of special creams, mosquito nets);
- regular medical examinations if infection is suspected and for prevention;
- Strengthening immunity, including by consuming garlic, oranges, carrots, green tea, dried fruits, rice porridge;
- 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 of where single-celled parasites live, help to choose the priority among the mentioned preventive measures.
With proper prevention and surgical treatment in the event of illness, parasites do not harm your body.