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 easily diagnosed as groups with more complex organizations. For convenience, in the article they are presented in a table with the main features.
Features
The simplest include organisms with primitive organizations, which are incorporated into the phylum Protozoa. It has more than 15 thousand species, and some of them live a parasitic lifestyle in the human body. All of them are characterized by small size, they can only be seen with a microscope, and it is impossible to see them with the naked eye.
Most of the simplest parasites have very primitive structures. Once inside the host body, they begin to reproduce. Sometimes this happens by dividing into two parts, and sometimes by multiple parts. In the latter case, the disease progresses rapidly, symptoms appear quickly, sometimes capable of eventually leading to a person's death.
Biological characteristics
The human parasitic organism of protozoa consists of two main parts: the nucleus and the cytoplasm, where all the other organelles are located. The core can be one or more.
Protozoa have the ability to form cysts if environmental conditions become unfavorable. Because of this, they are able to remain viable for a long time, remain immobile and perform without nutrients. Once the condition returns to normal, the cyst shell is destroyed, and the microorganism resumes its normal function. Encystation also allows parasites to successfully spread from organism to organism.
All protozoa are divided into several categories depending on their anatomy, mode of movement and other characteristics:
- flagella;
- sarcode
- sporozoa
- ciliates.
Within each group, there are species of which humans are intermediate or ultimate hosts.
The main type
Protozoa type parasites cause many diseases and parasitize in different organs. For convenience, they are presented in a table.
| name | Infected body parts | Methods of infection | symptoms |
|---|---|---|---|
| Balantidia | lower intestine | Eat uncooked pork or water with cysts | Balantidiasis is often accompanied by diarrhea. White mucus appears and blood comes out in the stool. The mucosa of the colon is ulcerated, and in such cases, bleeding may increase. With the progression of the disease, fatigue of a person occurs, in rare cases it can lead to death. |
| amuba mouth | Oral cavity, gum pockets, dental plaque | A person is 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, oral amoeba feed on epithelium, microbes, leukocytes and erythrocyte cells. May cause periodontal disease. |
| amoebic dysentery | Through the bloodstream it permeates into the lungs, liver, heart, genitals, kidneys. Settled in the intestinal lumen | Swallowed with food or water | In some cases, the disease is asymptomatic. If the dysentery amoeba invades the intestinal wall, then the pathogenic stage begins. It is characterized by colitis, tissue necrosis, liver damage, abscesses may appear. Very severe consequences cause metastasis to the brain and other organs. Possible fatal outcome. Sometimes the disease takes a recurrent course. Rarely does self -healing occur |
| Giardia usus | Duodenum and bile ducts. | oral route | Giardia attaches to the mucous epithelium and impairs nutrient absorption. Inflammation of the mucosa and diarrhea continue to develop. If the infection covers the bile ducts, yellowing of the skin appears. 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, as well as during childbirth from mother to child | Trichomoniasis is manifested by foamy discharge, itching and burning on the mucous membranes of the genitals, pain during intercourse, the appearance of bloody discharge from the urethra, etc. Complications of trichomoniasis are inflammation of the vulva due to protozoal activity, cystitis, prostatitis and infertility. |
| Trypanosoma brussei | Cerebrospinal fluid and brain | After being bitten by a tsetse fly, which is an intermediate host | It starts with fever and swelling of the lymph nodes, continues with apathy, irresistible desire for sleep, muscle paralysis and fatigue. If left untreated, coma and death ensue. |
| Skin leishmania | Contact with sick people or animals | On the skin, most often on the face or hands | The incubation period lasts from 2 months to 5 years, after which dense brown nodules appear at the site of the insect bite. It increased, and then the purulent ulcer opened in its place. The disease lasts up to several years, and then the last scar of the wound occurs. Complications can be disorders of the heart, kidneys and adrenal glands. |
| Toxoplasm | Infected pets, especially cats, sometimes the infection occurs when eating food with protozoa | Liver, liver, eyes, brain | In the congenital form - various pathologies of fetal development, death in infancy, mental retardation, various infections. Acquired toxoplasmosis causes high fever, enlargement of the liver, headache, vomiting, seizures. Often take a chronic course with increased fatigue and eye damage. Rarely in latent form |
| Isospora | From people infected with fecal-oral transmission | small intestinal epithelium | The incubation period lasts about 10 days. Then the body temperature rises, vomiting and diarrhea appear. The disease is acute for a week or two, then recovery occurs |
| Crypto sporidia | oral route | Intestinal epithelial tissue | The incubation lasts about a week, then diarrhea begins, possibly with the inclusion of spots. Stomach may ache, fever may appear, signs of dehydration may be. With an inadequate immune status of the patient, the infection can affect other organs: lungs, pancreas, stomach, etc. |
Is the simplest worm
Sometimes you can hear the phrase that patients are infected with worms most easily. It should be understood that protozoa are unicellular microorganisms that exclusively, in extreme cases, organize colonies. But they were never multi -celled like worms and helminths.
In protozoa, all processes take place in the cell cytoplasm and cell nucleus, while in worms, the anatomical organization is more complicated: they have different organs that perform special physiological functions. Therefore, it is basically wrong to classify worms as protozoa.
Sometimes helminths are called the simplest parasites compared to insects: bedbugs, fleas, etc. , because the latter are much higher than the evolutionary ladder. In this interpretation, the name of the worm is allowed as protozoa.