Parasites in humans 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 more complex groups. For convenience, in the article they are presented in a table with the main characteristics.
Characteristic
The simplest consists of primitive organized organisms, which are combined into the Protozoa phylum. It has more than 15 thousand species, and some of them are parasites in the human body. All of them are characterized by their small size, which can only be seen with a microscope, not recognizable with the naked eye.
Many of the simplest parasites have extremely primitive structures. Once inside the host's body, they begin to multiply. Sometimes this happens by dividing into two halves and sometimes by multiple divisions. In the latter case, the disease develops rapidly, symptoms quickly appear, sometimes potentially even causing the death of a person.
Features of biology
The human parasitic unicellular organism consists of two main parts: the nucleus and the cytoplasm, which contains all the other organelles. The core can be one or more.
Protozoa are capable of forming cysts if environmental conditions are unfavorable. Therefore, they can survive for a long time, immobile and without nutrients. As soon as conditions return to normal, the capsule shell is destroyed and the microorganism resumes normal activity. Encystation also allows the parasite to spread successfully from one organism to another.
All protozoa are divided into several types depending on anatomy, mode of movement and other characteristics:
- rod;
- Fleer
- sporozoans
- branch.
Within each group, there are species for which humans are intermediate or final hosts.
Main types
Parasites belong to the category of Protozoa that cause many diseases and parasitize different organs. For convenience, they are presented in the table.
| Name | Infected body parts | Mode of infection | Symptom |
|---|---|---|---|
| Balantidia | lower intestine | Eat undercooked pork or water with cysts | Balantidiasis is often accompanied by diarrhea. The stool appears white and bloody mucus. The lining of the colon is ulcerated, and in these cases, bleeding may increase. With the progression of the disease, a person's exhaustion occurs, which in rare cases can lead to death. |
| oral amoeba | 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 without pathological lesions in the oral cavity. During inflammation, the amoeba feeds on the epithelium, bacteria, white blood cells, and red blood cells. May cause periodontal disease. |
| amoebic dysentery | Through the bloodstream, it enters the lungs, liver, heart, genitals, and kidneys. Deposited in the gut | Ingestion of food or water | In some cases, the disease has no symptoms. If the pathogenic amoeba attacks the intestinal wall, the pathogenic phase begins. It is characterized by colitis, tissue necrosis, liver damage, and possibly abscesses. Very serious consequences are metastases to the brain and other organs. The outcome can be fatal. Sometimes the disease has a relapse. Rarely occurs self-healing |
| Intestinal Giardia | The duodenum and biliary tract. | oral route | Giardia adheres to the mucosal epithelium and impairs nutrient absorption. Mucositis and diarrhea continuously develop. If the infection covers the biliary tree, the skin is yellow. Some people develop an 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 gland and in the urethra | When having sex, as well as when giving birth from mother to child | Trichomoniasis is manifested by foamy discharge, itching and burning on the genital mucosa, pain during sexual intercourse, blood secretion from the urethra, etc. Complications of trichomoniasis are yin infections. due to the activities of protozoa. , cystitis, prostatitis and infertility |
| Trypanosoma brussei | Cerebrospinal fluid and brain | After being bitten by a sawtooth fly, which is an intermediate host | It begins with fever and swollen lymph nodes, continues to be lethargic, too eager to sleep, to muscle paralysis, and to exhaustion. If left untreated, coma and death can occur. |
| Leishmania da | 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, then a dense brown nodule appears at the insect sting site. It rises, and then a purulent ulcer opens in its place. The disease lasts up to several years, then leaves the final scarring of the wounds. Complications can be heart, kidney, and adrenal disorders. |
| Toxoplasma | Infected domestic animals, mainly cats, sometimes become infected by eating food containing protozoa | Liver, heart, eyes, brain | In congenital form - many pathologies of fetal development, infant death, mental retardation, superinfection. Acquired toxoplasmosis causes high fever, hepatomegaly, headache, vomiting, and convulsions. Often take a chronic course with an increase in fatigue and eye damage. Rarely occurs in latent form |
| Isospora | From a person with a fecal-oral disease | epithelium of the small intestine | The incubation period is about 10 days. Then the body temperature rises, vomiting and diarrhea appear. Illness develops acutely for a week or two, then recovers |
| Crypto sporidia | oral route | The epithelial tissues of the intestine | The incubation period lasts about a week, after which diarrhea begins, which may be accompanied by spotty stools. Abdominal pain, fever, and signs of dehydration may appear. With the patient's immune status insufficient, the infection can affect other organs: lungs, pancreas, stomach, etc. v. |
Are worms the simplest?
Sometimes you may hear the simplest worm infection patient phrase. It must be understood that protozoa are single-celled microorganisms that, in severe cases, organize colonies. But they are never multicellular like worms and flukes.
In protozoa, all processes take place in the cytoplasm and nucleus, while in worms the anatomical organization is much more complex: they have differentiated organs to carry out their functions. special physiology. Therefore, it is fundamentally wrong to classify worms as protozoa.
Sometimes helminths are called the simplest of insects: aphids, lice, etc. v. , as they are much higher up the ladder of evolution. In this understanding, the name of the worm is allowed to be protozoa.