Human parasites are represented by several groups, one of which is that of 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, in the article they are presented in a table with the main characteristics.
Characteristic
The simplest include organisms with a primitive organization, which are combined in the protozoan phylum. 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 size, they can only be seen under a microscope and it is impossible to notice them with the naked eye.
Many of the simpler parasites have an extremely primitive structure. Once in the host's body, they begin to multiply. Sometimes this happens by dividing into two halves and sometimes by multiple division. In the latter case, the disease develops rapidly, symptoms appear quickly, sometimes capable of causing even the death of a person.
Characteristics of biology
The organism of human parasitic protozoa 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. For this reason, they are able to remain viable for a long time, remaining still and without nutrients. As soon as the conditions return to normal, the shell of the cyst is destroyed and the microorganism continues its normal functioning. Encystation also allows parasites to successfully spread from one organism to another.
All protozoa are divided into several categories depending on the anatomy, mode of movement and other characteristics:
- flagella;
- sarcode
- sporozoa
- ciliates.
Within each group, there are species for which humans are the intermediate or final host.
Main types
Parasites of the Protozoa type cause many diseases and parasitize in different organs. For convenience, they are presented in the table.
| First name | Infected body parts | Method of infection | Symptoms |
|---|---|---|---|
| Balantidia | lower intestine | Eat raw pork or water with cysts | Balantidiasis is often accompanied by diarrhea. White mucus and bloody secretions appear in the stool. The mucous membrane of the colon ulcerates and, in these cases, bleeding may increase. As the disease progresses, a person's exhaustion occurs, in rare cases it can lead to death. |
| amoeba of the mouth | Oral cavity, gum pockets, dental plaque | A person becomes infected by kissing a courier, 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 feeds on epithelium, microbes, leukocytes and erythrocyte cells. It can cause periodontal disease. |
| dysenteric amoeba | Through the bloodstream it enters the lungs, liver, heart, genitals, kidneys. It settles in the intestinal lumen | 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 appear. Very serious consequences cause metastases to the brain and other organs. Possible fatal outcome. Sometimes the disease has a relapsing course. Self-healing rarely occurs |
| Intestinal giardia | Duodenum and bile ducts. | orally | Giardia attaches itself to the mucous epithelium and impairs the absorption of nutrients. Mucosal inflammation and constant diarrhea develop. If the infection covers the bile ducts, yellowness of the skin appears. Some people develop immunity to intestinal giardia, especially in countries with a tropical climate. |
| Vaginal trichomonas | 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 membrane of the genital organs, pain during sex, the appearance of bloody secretions 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 brain | After being bitten by a tsetse fly, which is an intermediate host | It begins with fever and swollen lymph nodes, continues with apathy, an irresistible desire to sleep, muscle paralysis and exhaustion. If left untreated, coma and death occur. |
| Cutaneous 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 lump appears at the site of the insect bite. It increases and a purulent ulcer opens in its place. The disease lasts up to several years, then final wound healing occurs. Complications can be heart, kidney and adrenal gland disorders. |
| Toxoplasma | Infected pets, mainly cats, sometimes an infection occurs when eating food with protozoa | Liver, heart, eyes, brain | In the congenital form - multiple pathologies of fetal development, death in childhood, mental retardation, multiple infections. Acquired toxoplasmosis causes high fever, enlarged liver, headache, vomiting, seizures. It often takes a chronic course with increased fatigue and eye damage. It rarely occurs in a latent form |
| Isospore | From infected person with fecal-oral transmission | epithelium of the small intestine | The incubation period lasts approximately 10 days. Then the body temperature rises, vomiting and diarrhea appear. The disease is acute for one to two weeks, then healing occurs |
| cryptosporidia | orally | Epithelial tissues of the intestine | Incubation lasts about a week, then diarrhea begins, possibly with spotting inclusions. The stomach can hurt, fever appears, signs of dehydration are possible. With an insufficient immune status of the patient, the infection can affect other organs: lungs, pancreas, stomach, etc. |
Worms are the simplest
Sometimes you can hear the phrase that the patient is infected with the simplest worms. It must be understood that protozoa are exclusively single-celled microorganisms, in extreme cases, which organize colonies. But they are never multicellular like worms and helminths.
In protozoa all processes take place within the cell cytoplasm and cell nuclei, while in worms the anatomical organization is much more complicated: they have differentiated organs that perform particular physiological functions. Therefore, it is fundamentally wrong to classify worms as protozoa.
Sometimes helminths are called the simplest parasites than insects - bedbugs, lice, etc. , as the latter are much higher on the evolutionary ladder. In this interpretation, the name worms is admitted as protozoa.