What parasites can live in the human body and how to properly fight them?

Parasitology is the science that studies parasitic phenomena. The main task of this type of science is to study the relationship between parasite and host and their mutual influence, which also depends on environmental factors.The role of parasitology in healthcare in the modern world has increased several times due to the increase in population migration (the development of tourism, due to the increase in the number of people coming from different countries). Next let's consider which parasites can survive in the human body and what symptoms various infections can cause.The number of immunocompromised patients has increased, including those living with HIV, also due to medical advances related to the use of chemotherapy and transplantation.All of this leads to the fact that most diseases (infections) caused by parasites usually have no complications or no symptoms at all, but can be fatal in people with weakened immune systems.The response of these patients to the introduction of parasites differs significantly from the usual response, leading to the development of an acute, atypical form of the disease.In addition, population activities cause changes in global climate conditions and natural landscapes, leading to the spread of infectious agents from endemic areas to other areas and regions.Medical parasitology is divided into several parts according to the different groups to which the parasitic organisms belong: protozoan parasites, helminthic parasites, parasitic arthropods, etc. Therefore, science is divided into:

1. Medical protozoology (study of parasitic protozoa, symptoms and treatment of protozoa);
2. Medical helminthology (the study of parasitic helminths, symptoms and treatment of helminth infections);
3. Parasitic entomology (the study of parasitic arthropods).

relationships between organisms

Parasitism is a special relationship between organisms of different species in which one (the parasite) uses another (the host) as a permanent or temporary place to live and as a source of food.The parasite does not kill the host immediately; first it must feed on the host repeatedly. During the course of evolution, parasites have developed special mechanisms for interacting with their hosts, ensuring the life activities of all parasitic species.External natural conditions do not directly affect the parasite, but indirectly through the host.Parasitism is quite common on Earth. Parasites can belong to any phylogroup of all biological kingdoms. Any type of organism except viruses can become a "home" for parasites.In this case, the parasitic individual itself becomes a host for parasites from other taxonomic groups of animals.Parasite extinction is the total number of absolutely all parasites living in a host at the same time. The causative agents of the disease are parasites specific to different host species. Parasites that live in their hosts not only feed but also cause various diseases that can lead to death in infected people. This phenomenon is called pathogenicity.Parasites in the human body negatively impact the body through a variety of mechanisms:

1. Cell and tissue damage;
2. Impact on host immune defense mechanisms and antibody production;
3. Hypersensitivity (hypersensitivity) to the host organism;
4. Toxic effects of parasite metabolites.

The developmental cycle of a parasite is the total number of morphological stages of an organism's development, along with an indication of habitat, infection, and transmission routes for each stage.For example, the development of a parasite can be divided into the following stages: Invasive stage – entry into the host; Larval formation stage; Adult, sexually mature individual stage.Invasive diseases (infestations) are diseases caused by parasitic organisms. Invasive diseases in humans are divided into protozoa (caused by protozoa), helminthiasis (parasitic diseases) and diseases caused by arthropod parasitism.The symptoms of parasites in the human body are so diverse that it makes no sense to consider them as a whole. Therefore, next we will consider the symptoms caused by the invasion of major protozoa, helminthiasis, and other animal organisms.Due to the need to persist in a parasitic lifestyle, there are three types of parasitism:

1. Pseudoparasitism. A free-living individual accidentally enters the body of a host, which may survive for a period of time and be able to disrupt its normal life processes. Pseudoparasites are quickly released into the environment (e. g. , in feces) or die within a short period of time. Some leeches are pseudoparasitic, and they accidentally enter the nasal cavity of people's lives and cause bleeding; mites and their eggs enter the stomach and are then excreted in the form of feces; there are also some amoeba.
2. Facultative parasitism is the ability of an organism to survive with or without a host. The viability of the parasite lasts longer than in the first case. This type is characteristic of fly larvae, which are capable of developing outside the organism and when accidentally entering the organism (the causative agent of myiasis).
3. True parasitism. Such parasites include worms, fleas, lice, etc.

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related to the owner’s body
ectoparasites	They live on the surface of the body's skin and feed on blood cells and the upper layers of skin.
internal parasites	They live within the tissues, cells, and cavities of their hosts. They can only be located in one of the organs, but can move to nearby organs and also cause damage
According to the length of contact
temporary parasitism	Most often, they are ectoparasites; their exposure is usually short-lived
Fixed parasites	For such parasites, the host is also a kind of "home". This parasitic lifestyle is divided into two types: cyclic (where the parasite spends part of its time inside the host) and permanent
by specificity
multispecific	Able to alter different types of hosts as they feed on blood, epidermis and other tissues native to a variety of organisms
monospecific	Can only parasitize hosts of certain species (species)

Owner's philosophy

A host is a living organism that the parasite uses as a source of nutrition and a place for survival. Most individual parasites can change hosts due to the multiple stages the parasite has during its life.The definitive host (or primary, final, final) is the organism in which the parasite lives in its adult stage and can reproduce sexually.The intermediate host is the host in which the larval stage of the parasite lives or the stage in which it reproduces only asexually.Reservoir host - in which the parasite survives, increases in number, but does not mature further.Parasitic diseases can be anthropogenic diseases (the source and host of the disease are humans), zoonotic diseases (the source and host are humans and animals), and zoonotic diseases (the source and host are animals).Many infections are known as natural focus infections when pathogens move among wildlife in an area.

Diagnostic methods for parasitic infections

You cannot use "magic pills" or home remedies to eliminate "internal parasites", but will cause greater harm to yourself. First, you need to understand what kind of intrusion a person has. To diagnose invasive disease, macroscopic, microscopic, and immunological methods can be used.Macroscopic techniques make it possible to identify the source of infection on the external surface of an infected person or in the feces.Microscopic methods can also identify parasites in blood smears, tissue fluids, muscle tissue biopsies, and in sputum, stool, gastric and duodenal contents.In parasitological research, light and electron microscopy methods of light and electron microscopy are used. Here, diagnosis is first based on an in-depth knowledge of the morphological structure of the infectious agent, preparation of smear preparations, fixation and staining methods.The results of microscopic examination depend on the choice of pathological material, its nature, the time of collection from the onset of symptoms and the time of examination from the moment of receipt of the material. Immunological diagnostic methods include serology and anaphylaxis. Serology tests are used for:

1. Use immunodiagnostic sera to determine the type of organism, toxin, and antigen;
2. Diagnostic antigens are used to determine the nature of the antibodies in the serum.

Basic serological reactions include agglutination, precipitation, lysis, complement fixation, neutralization and other reactions. Methods using labeled antibodies are also known: immunofluorescence reaction, enzyme-linked immunosorbent assay, western blot, radioimmunoassay.Nucleic acid hybridization and polymerase chain reaction methods have been widely used for diagnosis.

Problems with prevention and anti-epidemic measures

Preventive measures for all parasitic diseases can be summarized as follows:

1. There is a need to protect soil and water sources from contamination from human and animal waste.
2. There is a need to improve densely populated areas and toilets.
3. Implement health supervision over land, water supply, and food production, transportation, and sales in densely populated areas.
4. It is very important to carry out veterinary health supervision in slaughterhouses, meat processing plants, markets, livestock farms, etc.
5. It is necessary to identify and treat infection carriers.
6. It is necessary to protect people from arthropods and promote personal knowledge to prevent parasitic diseases.

Anti-epidemic measures include proactively discovering infected people and carriers, registering and treating infected people, hospitalization and medical examination when necessary, and neutralizing or destroying sources of infection. Personal prevention is very important: hygienic measures, annual physical examinations, proper preparation for tourist trips, addressing drug prophylaxis.Chemoprophylaxis, the use of anthelmintic drugs 1 to 2 times a year in high-risk populations and endemic areas, was developed by the World Health Organization for disadvantaged and developing countries.

General properties of protozoa

Protozoa are single-celled organisms (eukaryotes) that have a nucleus.They are no larger than a millimeter in size and are found in every corner of the earth. Forms of protozoan parasitism are also divided into ectoparasites and endoparasites.Characteristics of protozoa:

1. The body is composed of a cell, which performs the functions of the cell and the organism as a whole. Body shapes can vary: variable, elongated, or spindle-shaped.
2. Some protozoa are covered only by a cell membrane, while others have an elastic membrane called a lamina.
3. The cytoplasm of a cell is divided into: ectoplasm (outer plasm) and endoplasm (endoplasm). The cytoplasm may contain one or more nuclei.
4. Nutrients enter in many ways: via pinocytosis (absorption), phagocytosis (active feeding), osmosis (uptake of substances due to differences in concentration), active transfer across membranes.
5. Gas exchange occurs throughout the cell due to osmotic components. Waste products are also released from the entire surface of the cell with the help of digestive vacuoles.
6. Single-celled organisms reproduce sexually and asexually.
7. Single-celled organisms have a variety of locomotion devices: pseudopods, flagella, and cilia. They can respond to stimuli through phototaxis, chemotaxis, thermotaxis, and other mechanisms.
8. Under adverse conditions, parasitic protozoa become cysts, that is, they are covered with a dense membrane. In the cystic state, vital processes cease.

Under favorable conditions, the cyst sheds its outer shell and transforms into a vegetative body, continuing active life.There is little difficulty in detecting parasitic protozoa in patient material. A smear and a drop of thick blood are usually examined.Fresh stool is usually examined using a heated table. To detect amebic cysts, Lugol's solution is added to the stool to stain the internal structures.By this time, all protozoa had been classified into the kingdom Protozoa, which included seven types, only three of which were of medical importance.

Sarcoid subtype

Sarcoid cells change shape; the cell membrane forms protrusions that can then return to their original shape, called pseudopodia.Because of them, cells move. Carnivores live almost everywhere: soil, freshwater bodies, oceans. Infectious diseases caused by the family Nodosauridae are common throughout the world, but are more common in tropical and subtropical regions.Pathogenic amoebae most commonly affect the human digestive system; these are intestinal parasites. Free-living amoeba species from other orders can also cause serious infections if accidentally ingested and deposited in the human body.To diagnose amebiasis, a microscopic examination of stool is required. They contain shreds of meat in the form of vegetative bodies or vesicles. When stool preparations are examined using a special heating stage, the pseudopodia of the amoeba and its forward movement can be detected.To treat amoebiasis, the drugs used are divided into several categories: contact agents, which act on the amoeba in the intestinal lumen; systemic tissue amebicides, which act on the amoeba that has penetrated the intestinal tract and other organ tissues. Pallasmatozoa.In addition to treatment, liver abscess aspiration may be performed if chemotherapy is ineffective or there is a threat of abscess rupture. The following table describes the major parasitic protozoa of the Carnosidae subtypes.

Flagellate subphylum

Representatives of the flagellar subtype, in addition to the cytoplasmic membrane, also have a tegument (such a shell provides a constant shape) and flagella (one or more). Flagella contain contractile fibrils that allow them to move. Some representatives of flagellates have an undulating membrane, within which the flagella / flagella are located without exceeding their limits.Flagella begin as energy-storing bodies. Some flagellates have a sheath—a dense cord within the body that provides support.The main signs and symptoms of infections represented by Giardia subtypes are shown in the table below.<头>

Representation/Localization	symptom	diagnosis
Giardia (Intestinal Giardia or Giardia)/Duodenum and Small Intestine	Nausea, heartburn, abdominal pain, bloating, heartburn, diarrhea, body intoxication, fatigue	Microscopy of duodenal contents, fecal examination, Giardia antibody ELISA
Intestinal Trichomonas (Trichomonas hominis/intestine)/lower small intestine, large intestine	Colitis, enterocolitis, cholecystitis, diarrhea	Detection of vegetative bodies and cysts in patient's liquid stool
Trichomonas vaginalis/vagina, cervical canal, urethra - females. Urethra, prostate, testicles - men	Female vaginitis, urethritis, itching and burning sensation in the vulva, and yellow foamy discharge from the vagina. Asymptomatic carriers, urethritis, prostatitis in men	Female vaginal secretions, male urethral secretions and prostate secretions, PCR, culture
Trichomonas tenax/oral cavity, respiratory tract, tonsils, gums	Dental caries, periodontal disease, ENT disease	imprint smear, culture
African trypanosomatids (Trypanosoma brucei gambiae and Trypanosoma brucei rhodesiense)/penetration site skin, lymph nodes in neck and back of head, blood	Fever, lymphadenopathy, rash, headache, drowsiness, trembling limbs, paralysis, slurred speech, coma, convulsions, fatigue, acute heart failure, death	Examine the bite site and biopsy the lymph nodes. Concentrated drop method and blood smear method, Wright's or Romanowski-Giemsa staining, cerebrospinal fluid examination. Experimental animal infection, RSK, RIF, ELISA
American Trypanosomiasis (Trypanosoma cruzi)/blood	The skin at the penetration site is swollen, nearby lymph nodes are swollen, the eyelids are swollen, and the parotid gland lymph nodes are swollen. The acute form in newborns can cause damage to the heart and brain, leading to fatal consequences. Chronic form of the disease in adults in childhood - cardiac arrhythmias, extrasystoles, hypertrophic dilation of the colon wall, esophageal enlargement, myxedema, paralysis	Microscopy of blood smears, biopsy samples of lymph nodes, spleen and other organs - for the acute form. Serological studies, xenodiagnosis (feeding uninfected bacteria from patients and testing their feces for trypanosomes), infections in laboratory animals - chronic phase
Cutaneous Leishmaniasis (Leishmania tropicalis)/Skin	Skin nodules, regional lymphadenopathy, lymph node ulceration with the formation of "dry" or "wet" painless ulcers, sublesions, scars on the skin after healing	Microscopic examination of tissue at ulcer base using Romanowski-Giemsa stain, RIF, RSK, ELISA
Mucocutaneous Leishmaniasis (Leishmania braziliensis)/Skin and Mucosa	Skin nodules, local lymphadenopathy, skin ulcers, and scar formation. On the mucosa - painless deforming lesions of the mouth and nose, ulcers on the tongue, mucous membranes of the cheeks and nose, disruption of the nasal septum, hard palate, pharynx, fever, weight loss, increased bacterial infections	Microscopic examination of ulcer secretions, biopsy of damaged organs, RSK, RNGA
Visceral leishmaniasis (Leishmania donovani)/spleen cells, liver cells, bone marrow cells, lymph node cells	Enlarged liver and spleen, anemia, fatigue, poisoning, intestinal bleeding, diarrhea, gray spots on face and head, death	Spleen, lymph node, bone marrow biopsy smear, RIA, ELISA, RSK test

Sporaria

Sporozoites have no moving organs. They consume nutrients throughout the body and often exhibit intracellular parasitism. Sporozoans include the causative agents of malaria and Toxoplasma gondii. Toxoplasmosis is more dangerous for pregnant women and people with proven immunodeficiency (for example, in the context of HIV infection).Pregnant women with toxoplasmosis need to take 3 million units of spiramycin three times a day for 14 to 20 days.

parasitic ciliate

Ciliates do not change the shape of their bodies and have membranes. Movement manipulation occurs due to the large number of cilia covering the entire cell.Ciliates have two nuclei: a large nucleus responsible for cell metabolism, and a smaller nucleus that transmits genetic information.Ciliates have an organized digestive system: the cytoostome is the mouth of the cell and the cytopharynx is the pharynx of the cell. Digestive enzymes are gradually released from the vacuoles, ensuring complete digestion of nutrients. The undigested portion of food is expelled through powder, a special structure at the end of the body. Symptoms that may occur when these parasites are present in the intestines are listed in the table below.<头>

pathogen	localization	symptom	diagnosis
E. coli	colon	Fever, poisoning, abdominal pain, diarrhea with mucus and blood, nausea, vomiting. Asymptomatic, cyst carrier	Testing in stool and colon biopsies

Treatment of ballantiasis involves prescribing antibacterial and antiprotozoal drugs according to one of the following regimens.

General characteristics of worms

Helminthology is the science that studies the worms that live in other animals, the diseases they cause, and methods of diagnosis, prevention, and treatment.The helminth fauna is the sum total of all worms discovered by humans. Unlike diseases caused by protozoa, helminthiasis is uncommon.Most worms inhabit the human digestive tract, and others can attack parenchymal organs, blood, and the genitourinary system.The spread of worms depends on the labor activity of the population, the dietary habits of different groups of people, and the economic status of the country. The following helminth diseases are the most common in our country.Helminthiasis is divided into soil helminthiasis and biological helminthiasis. For soilworm eggs or larvae to develop, they need to mature in the external environment and acquire pathogenic properties. These are roundworms, whipworms, hookworms, etc.The life cycle of biological worms requires alternative hosts, and in order to acquire pathogenic properties, their eggs need to enter intermediate hosts and sometimes additional hosts. These are cattle, pork tapeworms, opisthorchis, Fasciolopsis, etc.The localization of parasites or their larval forms in the human body is very diverse: small and large intestine (intestinal helminthiasis), biliary tract and liver, blood, central nervous system and eyes, skin, muscles, etc. Intestinal parasites occur more commonly in humans than in fabrics.In the pathogenesis of helminthiasis, the occurrence of allergic reactions and severe degenerative processes is of great importance. They arise due to the large number of antigens that the worms possess.Other factors in the pathogenesis include the direct influence of enzymes that form the larval form and adult individuals. During later stages of worm development, mechanical factors and direct trauma to immobilized organs play an important role.Diagnosis is usually confirmed by interview, clinical manifestations of disease, and detection of eggs, larvae, fragments, or adult worms in stool, sputum, and duodenal fluid.Serological reactions, X-rays, and ultrasonography also play an important role in the diagnosis of helminthiasis.Generally speaking, there are about 300 species of pathogenic helminths found in humans, of which 28 are the most widely distributed: 12 species of flukes, 8 species of tapeworms, and 8 species of nematodes.