Parasites in biology are considered to be organisms that carry out their vital activity at the expense of another organism of another biological species.
Such vital activity of the parasite is of no benefit to the host organism, and in the best case the interaction does not lead to the development of negative effects.
In the worst case, the parasite causes the host's death. In this case, either the parasite escapes into the external environment or the common death.
Human parasitic diseases have been known practically since the primitive era of human existence. This fact was found in observing the behavior of the great apes' immediate ancestors. The parasites living in the wool are discovered by monkeys and separated from each other. This process has a very important character of social interaction.
The intolerance of humans to the appearance of acne and skin holes also has its origin in the early era of human existence. Some insect parasites in tropical areas can lay their larvae in the skin. This creates a reflex urge to push them out of the skin.
Various helminths that affected the eyes, skin and gastrointestinal tract have been described by ancient scientists. In the 18th and 19th centuries, with the development and introduction of microscopy into medical practice, scientists established the causes and routes of transmission of parasites that can cause certain diseases in humans.
- The beginning of the 20th century and the discovery of antiparasitic drugs made it possible for mankind to cope with most parasitic diseases.
Thus, humanity has existed very closely with various parasites for almost all of its history. However, modern medicine makes it possible to diagnose the full spectrum of parasites quickly and fairly accurately, which gives doctors the opportunity to treat such diseases in the shortest possible time and with minimal risk to patients.
The general practitioner helps identify parasites in the human body, symptoms and treatment. Sometimes infectious disease specialists with a narrower specialization - parasitologists - can be involved.
What are parasitic diseases?
Parasitic diseases are nosologies that occur after the introduction (penetration) of biological agents into the body. The latter are known as the group of human parasites. The symptoms of such diseases are extremely diverse and depend precisely on the active ingredient that has taken root and carries out its life activity in the body.
Depending on how parasites affect the human body, they are usually divided into the following groups:
- Exoparasites that affect human skin and hair.
- The toxic effect of the parasite's waste products on the body.
- Damage to the mucous membranes of the gastrointestinal tract and the lungs by a parasite.
- Formation of cysts and cysts in human organs. Enlargement of such cysts and cysts leads to specific symptoms of organ compression.
- Disruption of the normal passage of food through the gastrointestinal tract. This can lead to intestinal intussusception (more common in children) or the development of intestinal obstruction.
- Parasites living in a person can cause sensitization and the occurrence of non-specific allergic reactions.
- Microparasites can disrupt the function of blood cells and cause fever and poisoning.
- The influence of certain types of parasites on the body not only leads to severe symptoms, but can also lead to organ failure or death.
Such a wide variety of negative effects of parasites that appear in the body is due to various biological species that are introduced into human organs. However, such a biodiversity of the parasites living in the human body allowed doctors to identify specific signs of parasitic diseases.
Parasites living in the human body
The main routes of human infection with parasites depend on the life cycle of the biological organism that is the causative agent of the parasitic disease.
Doctors identify such ways for the parasite to invade a person as:
- contact path.It is characteristic of insect exoparasites, as well as some helminths that live mainly in water and whose larvae penetrate under human skin. They can be infected in this way from a sick person as well as from contaminated laundry, bedding, personal or public hygiene items, etc.
- Faecal-oral route of infection. Occurs when the pathogen's cysts enter food after contact with infected feces, mainly from animals. Autoinvasion can also be observed - self-infection of a person when personal hygiene is not observed, and so on.
- contamination.The pathogen enters the bloodstream when infected insects are crushed.
- Permeable infection.The parasite enters the bloodstream when it is bitten by an insect that carries the disease. This transmission route is mostly characteristic of the simplest parasites, for example malaria.
- Sexually transmitted infection.It is typical of STDs caused by parasites and some helminths that can affect a person's urinary and genital tracts.
Protozoa, helminths (roundworms and flatworms), insects and some types of fungi are attributed to the causes of parasitic diseases.
The incidence of humans with these species depends on the geographical and climatic zone. Therefore, medicine in each country keeps its own record and list of parasites specific to it.
Biological organisms that enter the human body have been extensively studied by both medical biologists and doctors, which has made it possible to clearly classify all biological species that can cause parasitic diseases:
- The simplest organisms (amebiasis, balantidiasis, babeose, Chagas disease, leishmaniasis, malaria, giardiasis, trypanosomiasis, toxoplasmosis, trichomoniasis).
- helminths. Sometimes the term worms is used (ascariasis, dicroceliosis, diphyllobothriasis, dranculosis, clonorchiasis, opisthorchiasis, strongyloidiasis, teniasis, fascioliasis, schistosomiasis, enterobiasis, echinococcosis).
- Exoparasites (louse (pubic, head, clothing), demodicosis, fleas, beetles, scabies).
Signs of parasites in the human body
Unfortunately, there are no precise signs of parasites in the human body and no symptoms that would indicate this or that type of parasitic infection. As a result, specific tests are required for an accurate diagnosis, such as helminthiasis.
On the other hand, almost all exoinfections are diagnosed very easily - based on the clinical picture and the presence of a certain type of insect on the skin.
In general, all symptoms of parasitic diseases can be divided into the following groups:
- Itching and discomfort of the skin from external hair and skin parasites (fleas, lice and others). An acne-like itchy rash is often associated with a condition such as demodectic mange (a special type of mite).
- Pain in various parts of the body caused by the introduction of a parasite into the skin and muscles (some types of worms that live in water).
- Eye pain, blurred vision.
- Lung pain, mucous cough (this situation can be typical of the migration of Ascaris larvae in the lungs, as well as with echinococcal cysts of the lungs, etc. ).
- Nausea, vomiting, and diarrhea are very common symptoms of most helminths that parasitize the digestive tract.
- Jaundice, diseases of the liver and biliary tract, liver failure. These symptoms occur with helminths that affect the liver and biliary tract, as well as with malaria at the height of the disease.
- stomach pain.
- Intestinal obstruction due to occlusion of the intestinal lumen with a large number of roundworms or large representatives of flatworms.
All these symptoms of the presence of parasites in the human body should prompt the doctor to think about a parasitic human disease and serve as a basis for diagnostic and laboratory studies, since there is no data on any other pathology.
Diagnosis of parasites in humans
Depending on the type of parasite that has entered the human body, one or another examination is carried out. When it comes to external exoparasites, which are mostly insects, diagnosis of the disease is usually limited to a general examination, as well as insect microscopy.
The general examination usually provides an accurate diagnosis and appropriate treatment or disinfection of the scalp or skin. In the case of demodicosis or scabies, the diagnosis is easily made based on the location of the rash and the presence of itching.
In this case, scratches removed for microscopy confirm the diagnosis of intradermal parasites.
For gastrointestinal parasites, the main screening study (a diagnostic tool that allows you to quickly and relatively informatively assess data about the presence or absence of the disease in a large number of people) is the analysis of feces.
- With a special microscopic examination of the feces, the laboratory assistant assesses the presence of eggs from worms, dead worms, cyst capsules, etc.
Using the morphology of worm eggs, you can almost accurately determine the type of worm that parasitizes in the body. Sometimes the tapeworm segments are macroscopically determined in the feces. They are then examined under a microscope to determine the appearance of a flatworm parasitizing the gastrointestinal tract.
In some cases, for example when the diagnosis of parasites in the body is not possible or meaningful by analyzing the feces, immunological studies are used. With them you can judge the presence of antibodies to a specific type of helminth. Due to the particular immunological relationship between the human immune system and the parasite, in some cases the level of antibodies may not reflect the true picture of the disease.
In malaria, a thick drop of blood is tested to detect Plasmodium malaria. In addition, the general blood count, the leukocyte values and all biochemical parameters of the blood, especially the liver, are evaluated.
The presence of an increased level of blood eosinophils is a common sign not only of allergic diseases, but also of helminthic invasions. This is the first "bell".
Sometimes helminths in the gastrointestinal tract are a diagnostic finding during contrast radiography, cystoscopy, FGDS, and colonoscopy.
How are parasites eliminated in the human body?
The treatment of parasitic infections should only be carried out by a doctor under certain rules.
Self-medication and traditional medicine do not lead to improvement in such cases and can sometimes be fatal.
It is also important to treat all family members and contacts preventively.
Human exoparasites that parasitize hairy areas of the body are destroyed with special disinfectants. Usually a single treatment followed by a hygienic wash is enough to kill exo parasites.
When it comes to skin types from parasites (scabies, demodicosis), special ointments are used that contain insecticides against such organisms.
Antihelminthics are used against roundworms and flatworms, which have a special effect on helminths in the main lumen of the gastrointestinal tract. Depending on the biological nature of the helminth, various treatment regimens are used (from a tablet to a series of courses).
Such drugs should only be used under medical supervision in order to recognize the negative effects and side effects of drugs in good time.
No other treatment methods, detoxification programs, etc. can lead to the complete death of parasites in the body and thus to the healing of a person.