Human parasites are represented by different groups, one of which is the protozoa. They are capable of causing diseases of varying severity, and these microorganisms are not as easy to diagnose as groups with more complex organization. For convenience in the article, they are presented in a table with the main characteristics.
Characteristic
The simplest include organisms with primitive organization, which are united in the type Protozoa. There are more than 15, 000 species, some of which lead a parasitic lifestyle in the human body. All of them are small in size, can only be seen with a microscope and it is impossible to see 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 happens by dividing in two halves, and sometimes by multiple divisions. In the latter case, the disease develops rapidly, the symptoms appear rapidly, sometimes capable of eventually even causing the death of a person.
Characteristics 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. Therefore, they are able to remain viable for a long time, remaining immobile and without nutrients. As soon as the conditions return to normal, the cyst sheath is destroyed and the microorganism continues to function normally. Encystation also allows parasites to spread successfully from organism to organism.
All protozoa are divided into several categories depending on the anatomy, mode of movement and other characteristics:
- flagella;
- sarcode
- sporozoites
- eyelashes.
In each group there are species for which humans are intermediate or final hosts.
Basic species
Protozoa parasites cause many diseases and parasitize various organs. For convenience, they are presented in the table.
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| name |
Infected parts of the body |
Method of infection |
Symptoms |
|---|
| Balantidia |
lower intestine |
Eating raw pork or water with cysts |
Balantidiasis is often accompanied by diarrhea. White mucus and bloody discharge appear in the stool. The lining of the colon ulcers and in such cases the bleeding may increase. As the disease progresses, a person becomes exhausted, in rare cases it can lead to death. |
| amoeba in the mouth |
Oral cavity, gum pockets, dental 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 feeds on epithelium, microbes, leukocytes and erythrocytes. May cause periodontitis. |
| dysenteric amoeba |
Through the bloodstream it penetrates the lungs, liver, heart, genitals, kidneys. It is established in the intestinal lumen |
Ingestion of food or water |
In some cases, the disease is asymptomatic. If the dysenteric amoeba attacks the walls of the intestine, then the pathogenic stage begins. It is characterized by colitis, tissue necrosis, liver damage, abscesses may occur. Very severe consequences cause metastases in the brain and other organs. Possible fatal outcome. Sometimes the disease has a recurrent course. Self-medication is rare |
| Intestinal Giardia |
The duodenum and bile ducts. |
oral route |
Giardia adhere to the epithelium of the mucosa and impair the absorption of nutrients. Inflammation of the mucous membranes and persistent diarrhea develop. If the infection affects 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 - on the vaginal mucosa, in men - in the epidermis of the prostate and urethra |
During sexual intercourse, as well as during childbirth from mother to child |
Trichomoniasis is manifested by frothy secretions, itching and burning on the mucous membranes of the genitals, pain during sex, the appearance of bloody discharge from the urethra and others. 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 starts with fever and swollen lymph nodes, continues with apathy, overwhelming desire for sleep, muscle paralysis and exhaustion. If left untreated, coma and death occur. |
| Skin 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 brownish dense nodule appears at the site of the insect bite. It increases and then a purulent ulcer opens in its place. The disease lasts up to several years, and then the final scarring occurs. Complications can be disorders of the heart, kidneys and adrenal glands. |
| toxoplasmosis |
Infected pets, mainly cats, sometimes infection occurs when eating food with protozoa |
Liver, heart, eyes, brain |
In congenital form - many pathologies of fetal development, death in early childhood, mental retardation, many infections. Acquired toxoplasmosis provokes fever, enlarged liver, headache, vomiting, convulsions. There is often a chronic course with increased fatigue and eye damage. It is rarely found in latent form |
| Isospora |
From an infected person with faecal-oral transmission |
epithelium of the small intestine |
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, after which recovery occurs |
| Cryptosporidium |
oral route |
Epithelial tissues of the intestine |
Incubation lasts about a week, after which diarrhea begins, probably with inclusions of spots. Stomach pain, fever, signs of dehydration may occur. In case of insufficient immune status of the patient, the infection can affect other organs: lungs, pancreas, stomach and others. |
Worms are the simplest
Sometimes you can hear the phrase that the patient is infected with the simplest worms. It should be understood that protozoa are exclusively unicellular microorganisms, in extreme cases, organizing colonies. But they are never multicellular like worms and helminths.
In protozoa, all processes take place in the cell cytoplasm and cell nuclei, while in worms the anatomical organization is much more complex: they have differentiated organs that perform special physiological functions. It is therefore fundamentally wrong to classify worms as protozoa.
Helminths are sometimes called the simplest parasites compared to insects: bedbugs, lice and others. as the latter are much higher in the evolutionary ladder. In this interpretation, the name worms is allowed as protozoa.
