Human parasites are represented by different groups, one of which is the protozoa. They can cause diseases of varying severity, and these microorganisms are not as easy to diagnose as more complex groups. For convenience, the article presents a table with key features.
It is typical
The simplest include organisms with primitive organisms that merge into the protozoan strain. There are more than 15, 000 species, and some of them lead parasitic lifestyles in the human body. All are small in size, only visible under a microscope and not noticeable to the naked eye.
Many of the simplest parasites have an extremely primitive structure. Once in the host, they begin to reproduce. This is sometimes done by dividing it into two parts, and sometimes by multiple divisions. In the latter case, the disease develops rapidly, with symptoms appearing quickly that can sometimes lead to the death of one person.
Characteristics of biology
The body of the protozoan human parasite consists of two main parts: the nucleus and the cytoplasm, which contains all the other organelles. The core may be one or more.
Protozoa are able to form a cyst if environmental conditions become unfavorable. As a result, they are able to remain viable for a long time, remain immobile and remain nutrient-free. As conditions return to normal, the cyst shell is destroyed and the microorganism resumes normal function. Encystation also allows parasites to successfully spread from organism to organism.
Each protozoan can be divided into several categories depending on anatomy, mode of movement, and other characteristics:
- flagella;
- sarcode
- sporozoa
- chilli.
Within each group, there are species of which man is the intermediate or final host.
Main types
Protozoa-type parasites cause a number of diseases and parasitize various organs. For convenience, these are shown in the table.
| Name | Infected parts of the body | Method of infection | Symptoms |
|---|---|---|---|
| Balantidia | lower intestines | Consumption of raw pork or cystic water | Balantidiasis is often associated with diarrhea. White mucus and bloody secretions appear in the stool. The mucous membranes of the colon become ulcerated and bleeding may increase in such cases. As the disease progresses, the person becomes exhausted and in rare cases can lead to death. |
| mouth amoeba | Oral cavity, gingival pockets, plaque | A person becomes infected by kissing a carrier, using dirty dishes, and eating contaminated food. | It rarely affects people who do not have a pathological change in the oral cavity. In inflammation, the oral amoeba feeds on epithelium, microbes, leukocytes, and erythrocytes. May cause periodontal disease. |
| dysentery amoeba | It penetrates the lungs, liver, heart, genitals and kidneys through the bloodstream. It settles in the lumen of the intestine | Ingestion with food or water | In some cases, the disease is asymptomatic. If the dysentery amoeba attacks the intestinal wall, the pathogenic stage begins. Colitis, tissue necrosis, liver damage, abscesses may occur. The very serious consequences cause metastases in the brain and other organs. Possible fatal outcome. Sometimes the disease has a relapsing course. Self-healing is rare |
| Intestinal Giardia | Duodenum and bile ducts. | orally | Giardia adheres to the mucous membranes of the mucosa and impairs the absorption of nutrients. Inflammation of the mucous membranes, permanent diarrhea. If the infection covers the bile ducts, yellowing of the skin will appear. Some people develop immunity to intestinal Giardia, especially in countries with tropical climates. |
| Trichomonas vaginalis | In women - on the vaginal mucosa, in men - in the epidermis of the prostate and in the urethra | During sexual intercourse and during childbirth from mother to child | Trichomoniasis is caused by foamy discharge, itching and burning of the mucous membranes of the genitals, pain during sex, bloody discharge from the urethra, and so on. Is manifested. Complications of trichomoniasis include inflammation of the vulva due to protozoan activity, cystitis, inflammation of the prostate, and infertility |
| Trypanosoma brussei | The cerebrospinal fluid and the brain | After being bitten by a whale fly, which is an intermediate farmer | It begins with fever and swelling of the lymph nodes, and continues with apathy, irresistible cravings, muscle paralysis, and exhaustion. If left untreated, coma and death can occur. |
| Skin leishmania | Contact with a sick person or animal | On the skin, most often on the face or hands | The incubation period lasts from 2 months to 5 years, after which a brown, dense lump appears at the site of the insect bite. It grows and then a purulent ulcer opens in place. The disease lasts for several years, after which the final scarring of the wounds occurs. Complications include heart, kidney, and adrenal dysfunction. |
| Toxoplasma | Infected pets, especially cats, sometimes become infected when they eat protozoan food | Liver, heart, eyes, brain | In congenital form - multiple pathology of fetal development, infant death, mental retardation, multiple infection. Acquired toxoplasmosis causes high fever, liver enlargement, headache, vomiting, convulsions. Often chronic, with increased fatigue and eye damage. It rarely occurs in a latent form |
| Isospora | From an infected person with faecal-oral transmission | small intestinal epithelium | The incubation period is about 10 days. Then the body temperature rises, vomiting and diarrhea occur. The disease is acute for a week or two, followed by recovery |
| Crypto sporidia | orally | Epithelial tissues of the intestine | The incubation lasts for about a week, after which diarrhea begins, possibly with spotted inclusions. Stomach pain, fever and signs of dehydration may occur. In case of insufficient immune status of the patient, the infection may affect other organs: lungs, pancreas, stomach, etc. |
Worms are the simplest
Sometimes you can hear the saying that the patient is infected with the simplest worms. It is to be understood that protozoa are exclusively unicellular microorganisms, in extreme cases colonies. But they are never multicellular like worms and helminths.
In protozoa, all processes take place in the cytoplasm and nuclei of the cell, while in worms, the anatomical organization is much more complex: they have differentiated organs that perform special physiological functions. Therefore, it is fundamentally incorrect to classify worms as protozoa.
Helminths are sometimes called the simplest parasites compared to insects: bugs, lice, and so on. Because the latter are much higher up the evolutionary ladder. In this interpretation, the name of the worm is allowed as a protozoan.