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, the article presents a table with the main features.
Characteristic
The simplest include organisms with primitive organization, which are combined in the genus Protozoa. It has more than 15 thousand species, and some of them lead a parasitic lifestyle in the human body. All of them are characterized by small sizes, can only be seen under a microscope and it is impossible to observe them with the naked eye.
Many of the simplest parasites have an extremely primitive structure. Once they enter the host's body, they begin to multiply. Sometimes this happens with a split in two, and sometimes with a multiple split. In the latter case, the disease develops rapidly, the symptoms appear quickly, sometimes capable of eventually causing even the death of a person.
Characteristics of biology
The body of protozoan human parasites consists of two main parts: the nucleus and the cytoplasm, in which all other organelles are located. The kernel may be one or more.
Protozoa have the ability to form cysts if environmental conditions become unfavorable. Because of this, they can remain viable for a long time, remaining immobile and without nutrients. Once the conditions return to normal, the bladder shell is destroyed and the microorganism continues to function normally. Inoculation also allows parasites to spread successfully from organism to organism.
All protozoa are divided into different categories depending on the anatomy, the way they move and other characteristics:
- whips?
- flesh
- spores
- eyelashes.
Within each group, there are species for which man is the intermediate or definitive host.
Main types
Protozoan parasites cause many diseases and parasitize various organs. For convenience, they are presented in the table.
| Name | Infected parts of the body | Method of infection | Symptoms |
|---|---|---|---|
| Ballads | lower intestines | Eating uncooked pork or water with cysts | Valadiasis is often accompanied by diarrhea. White mucus and bloody secretions appear in the stool. The mucosa of the colon is ulcerated and in such cases, the bleeding may increase. As the disease progresses, a person becomes exhausted, in rare cases it can lead to death. |
| oral amoeba | Oral cavity, gum pockets, dental plaque | A person becomes infected by kissing a player, using dirty dishes and eating contaminated food. | Rarely affects people who do not have pathological lesions in the oral cavity. In inflammation, the oral amoeba feeds on epithelium, germs, leukocytes and erythrocytes. May cause periodontal disease. |
| dysenteric amoeba | Through the bloodstream it penetrates the lungs, liver, heart, genitals, kidneys. It is installed in the intestinal tract | Ingestion with food or water | In some cases, the disease is asymptomatic. If the dysenteric amoeba invades the intestinal walls, then 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 recurrent course. Self-medication is rare |
| Intestinal Giardia | Duodenum and bile ducts. | oral route | Giardia sticks to the mucous epithelium and impairs the absorption of nutrients. Inflammation of the mucosa develops and persistent diarrhea. If the infection covers the bile ducts, yellowing of the skin occurs. Some people develop immunity to intestinal Giardia, especially in countries with tropical climates. |
| Trichomonas vaginalis | In women - in the vaginal mucosa, in men - in the skin of the prostate and in the urethra | During sexual intercourse, as well as during childbirth from mother to child | Trichomoniasis is manifested by foamy discharge, itching and burning in the mucous membrane of the genitals, pain during sexual intercourse, appearance of bloody secretions from the urethra, etc. cystitis, prostatitis and infertility |
| Trypanosoma brussei | Cerebrospinal fluid and brain | After being bitten by a cheetah fly, which is an intermediate host | It starts with fever and swollen lymph nodes, continues with apathy, irresistible desire for sleep, muscle paralysis and exhaustion. If left untreated, coma and death occur. |
| Cutaneous leishmaniasis | 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 dense brown nodule appears at the site of the insect bite. It grows, and then a purulent ulcer opens in its place. The disease lasts up to several years and then the final scar appears. Complications can be disorders of the heart, kidneys and adrenal glands. |
| Toxoplasma | Infected domestic animals, especially cats, sometimes become infected when eating protozoan food | Liver, heart, eyes, brain | In congenital form - multiple pathologies of fetal development, death in infancy, mental retardation, multiple infections. Acquired toxoplasmosis causes high fever, swollen liver, headaches, vomiting, convulsions. It often follows a chronic course with increased fatigue and damage to the eyes. 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 occur. The disease is acute for a week or two, and then recovery occurs |
| Crypto sporidia | oral route | Epithelial tissues of the intestine | The incubation lasts about a week, after which the diarrhea begins, possibly with spots. Stomach ache, fever may occur, signs of dehydration are possible. With an insufficient immune status of the patient, the infection can affect other organs: lungs, pancreas, stomach, etc. |
They are the simplest worms
Sometimes you can hear the phrase that the patient is infected by the simplest worms. It should be understood that protozoa are exclusively unicellular microorganisms, in extreme cases, organizational colonies. But they are never multicellular like worms and helminths.
In protozoa, all processes take place within the cytoplasm and cell nuclei, while in worms, the anatomical organization is much more complex: they have differentiated organs that perform specific physiological functions. Therefore, it is fundamentally wrong to classify worms as protozoa.
Worms are sometimes called the simplest parasites compared to insects: bedbugs, lice, etc. , since the latter are much higher on the evolutionary ladder. In this interpretation, the name of the worms is allowed as protozoa.