Human parasites are represented by different groups, one of which is protozoa. They are capable of causing diseases of varying severity, and these microorganisms are not as easy to diagnose as groups with a more complex organization. For convenience, they are presented in the article in a table with the most important features.
Characteristic
The simplest include organisms with a primitive organization, which are combined in Protozoa phylum. It has more than 15 thousand species and some of them lead a parasitic lifestyle in the human body. All are characterized by small sizes, they can only be seen with a microscope, and it is impossible to notice them with the naked eye.
Many of the simplest parasites have an extremely primitive structure. Once in the host's body, they begin to multiply. Sometimes this is done by dividing into two halves, and sometimes by multiple division. In the latter case, the disease develops rapidly, symptoms occur rapidly, sometimes capable of eventually causing a person's death.
Functions of biology
The organism of protozoan human parasites consists of two main parts: the nucleus and the cytoplasm, in which all other organelles are located. The core can be one or more.
Protozoa have the ability to form a cyst if environmental conditions become unfavorable. Because of this, they are able to remain viable for a long time, remain immobile and survive without nutrients. As soon as conditions return to normal, the cyst shell is destroyed and the microorganism continues its normal function. Encystation also allows parasites to spread from organism to organism.
All protozoa are divided into several categories depending on the anatomy, movement and other characteristics:
- flagella;
- sarcode
- sporozoer
- ciliates.
Within each group there are species for which humans are the intermediate or final host.
Main types
Protozoan parasites cause many diseases and parasites in various organs. For convenience, they are presented in the table.
| Name | Infected body parts | Method of infection | Symptoms |
|---|---|---|---|
| Balantidia | lower intestines | Eat uncooked pork or water with cysts | Balantidiasis is often accompanied by diarrhea. White mucus and bloody discharge appear in the stool. The intestinal mucosa forms ulcers, and in such cases the bleeding may increase. With the development of the disease occurs exhaustion of a person, in rare cases it can lead to death. |
| mouth amoeba | Oral cavity, gum 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 pathological lesions in the oral cavity. In inflammation, the oral amoeba lives off epithelium, microbes, leukocytes and erythrocyte cells. May cause periodontitis. |
| dysenteric amoeba | Through the bloodstream, it penetrates the lungs, liver, heart, genitals, kidneys. Lies in the lumen of the intestine | Ingestion with food or water | In some cases, the disease is asymptomatic. If the dysenteric amoeba attacks the intestinal walls, the pathogenic stage begins. It is characterized by colitis, tissue necrosis, liver damage, abscesses may occur. Very serious consequences cause metastases to the brain and other organs. Possible fatal outcome. Sometimes the disease takes a relapse. Rarely does self-healing occur |
| Intestinal Giardia | Duodenum and bile ducts. | oral route | Giardia adheres to the mucosal epithelium and damages the absorption of nutrients. Inflammation of the mucous membrane and constant diarrhea develop. If the infection covers the bile ducts, yellowing of the skin appears. Some people develop immunity to intestinal Giardia, especially in countries with a tropical climate. |
| Trichomonas vaginalis | In women - on the vaginal mucosa, in men - in the epidermis of the prostate and in the urethra | During intercourse, as well as during childbirth from mother to child | Trichomoniasis is manifested by frothy discharge, itching and burning of the mucous membranes of the genitals, pain during sex, the appearance of bloody discharge from the urethra, etc. A complication of trichomoniasis is inflammation of the vulva due to the activity of protozoa, cystitis, prostatitis and infertility. |
| Trypanosoma brussei | Cerebrospinal fluid and the brain | After being bitten by a tsetse fly, which is an intermediate host | Begins with fever and swelling of the lymph nodes, continues with apathy, an irresistible desire to sleep, muscle paralysis and fatigue. If left untreated, coma and death occur. |
| Kutan 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 brownish dense nodule appears at the site of insect bites. It increases and then a purulent wound opens instead. The disease lasts up to several years, and then the final scarring of the wounds occurs. Complications can be disorders of the heart, kidneys and adrenal glands. |
| Toxoplasma | Infected domestic animals, mainly cats, sometimes get infection when eating food with protozoa | Liver, heart, eyes, brain | In the congenital form - several pathologies of fetal development, death in infants, mental retardation, several infections. Acquired toxoplasmosis causes high fever, enlarged liver, headache, vomiting, cramps. Often takes a chronic course with increased fatigue and eye damage. Rarely occurs in latent form |
| Isospora | From an infected person with fecal-oral transmission | small intestinal epithelium | The incubation period lasts about 10 days. Then the body temperature rises, vomiting and diarrhea come. The disease is acute for a week or two, then improvement occurs |
| Crypto sporidia | oral route | Epithelial tissue in the intestine | The incubation lasts about a week, after which diarrhea begins, possibly with inclusions of spotting. Stomach may hurt, fever appears, signs of dehydration are possible. With insufficient immune status in the patient, infection can affect other organs: lungs, pancreas, stomach, etc. |
Worms are the simplest
Sometimes one can hear the phrase that the patient is infected with the simplest worms. It should be understood that protozoa are exclusively single-celled microorganisms, in extreme cases organizing colonies. But they are never multicellular like worms and helminths.
In protozoa, all processes occur in the cytoplasm and cell nuclei of the cell, while the anatomical organization of worms is much more complicated: they have differentiated organs that perform special physiological functions. Therefore, it is fundamentally wrong to classify worms as protozoa.
Sometimes helminths are called the simplest parasites in comparison with insects: bed bugs, lice, etc. , as the latter are much higher up on the evolutionary ladder. In this interpretation, the names of worms are allowed as protozoa.