Parasites in biology are considered to be those organisms that carry out their vital activity at the expense of another organism of a different biological species.
Such vital activity of the parasite does not bring any 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 death of the host. In this case, either the parasite escapes into the environment or co-death.
Human parasitic diseases have been known practically since the primitive era of human existence. This fact was established in the process of observing the behavior of the immediate ancestors of man - the apes. The parasites that inhabit the wool are detected by monkeys and removed from each other. This process has a very important character of social interaction.
Human intolerance to the appearance of pimples and holes in the skin also dates back to the early era of human existence. Some insect parasites in the tropics can lay their larvae on the skin. This leads to a reflex desire to squeeze them out of the skin.
Various helminths affecting 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 in medical practice, scientists established the causes and modes of transmission of parasites that can cause specific diseases in humans.
- The beginning of the 20th century and the discovery of antiparasitic agents allowed humanity to deal with most parasitic diseases.
In this way, humanity has coexisted very closely with various parasites throughout most of its history. However, modern medical science makes it possible to diagnose the full range of parasites quickly and accurately, which allows doctors to treat such diseases in the shortest possible time and with minimal risk to patients.
A general practitioner will help you identify parasites in the human body, symptoms and treatment. Sometimes specialists in infectious diseases with a narrower specialization - parasitologists - can be involved.
What are parasitic diseases?
Parasitic diseases are nosologies that occur after the introduction (invasion) of biological agents into the body. The latter belong to the group of human parasites. The symptomatology of such diseases is extremely diverse and depends exactly on the agent that has penetrated and carried out its vital activity in the body.
According to the way parasites affect the human body, they are usually divided into the following groups:
- Exoparasites that affect human skin and hair.
- The toxic effect of waste products from the parasite on the body.
- Damage to the mucous membranes of the gastrointestinal tract and lungs by a parasite.
- Formation of cysts and cysts in human organs. Increasing the size 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 intussusception (more common in children) or the development of intestinal obstruction.
- Parasites that live in humans can cause sensitization and the appearance of non-specific allergic reactions.
- Microparasites can disrupt blood cell function, causing fever and intoxication.
- The effect 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 variety of negative effects of parasites that occur in the body is due to different species that are introduced into human organs. Such a biological diversity of parasites living in the human body allows doctors to identify specific signs of parasitic diseases.
Parasites living in the human body
The main ways of infecting humans with parasites depend on the life cycle of the biological organism that causes the parasitic disease.
Doctors have identified ways for the parasite to enter humans such as:
- Contact path.It is characteristic of exoparasitic insects, as well as some helminths, which live mainly in water, whose larvae penetrate under human skin. You can be infected in this way by a sick person, as well as by soiled linen, bed linen, personal or public hygiene items, etc.
- Fecal-oral routeof infection. Occurs when cysts of the pathogen enter the food after contact with infected feces, mainly from animals. Autoinvasion can also be observed - self-infection of a person if personal hygiene is not observed, etc.
- Pollution.The pathogen enters the bloodstream when infected insects are crushed.
- Transmissible infection.The parasite enters the bloodstream when bitten by an insect that carries the disease. Most often, this route of transmission is characteristic of the simplest parasites, such as malaria.
- Sexually transmitted infection.It is characteristic of both sexually transmitted diseases caused by parasites and some helminths that can affect the human urinary tract and genitals.
Protozoa, helminths (round and flatworms), insects, and some species of fungi are among the causes of parasitic diseases.
The appearance of people with these species depends on the geographical and climatic zone. Therefore, the medicine of each country keeps its own records and a list of parasites that are characteristic of it.
The biological organisms that enter the human body have been studied in detail 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, babeosis, Chagas disease, leishmaniasis, malaria, giardiasis, trypanosomiasis, toxoplasmosis, trichomoniasis).
- Helminths. The term worms is sometimes used (ascariasis, dicroceliosis, diphyllobotriasis, dranculosis, clonorchiasis, opisthorchiasis, strongyloidiasis, teniasis, fascioliasis, schistosomiasis, enterobiasis, echinococcosis).
- Exoparasites (lice (pubic, heads, clothes), demodicosis, fleas, bugs, scabies).
Signs of parasites in the human body
Unfortunately, there are no exact signs of parasites in the human body and symptoms that indicate this or that type of parasitic infection. This leads to the fact that specific tests are needed for an accurate diagnosis, such as helminthiasis.
On the other hand, almost all exoinfections are diagnosed quite simply - 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 grouped into the following groups:
- Itching and skin discomfort caused by external hair and skin parasites (fleas, lice, etc. ). An acne-like itchy skin rash is often associated with a condition such as demodicosis (a special type of mite).
- Pain in various parts of the body caused by the introduction of a parasite into the skin and muscles (certain types of worms that live in water).
- Eye pain, blurred vision.
- Lung pain, sputum cough (this situation may be typical of the migration of roundworm larvae into the lungs, as well as echinococcal cysts of the lungs, etc. ).
- Nausea, vomiting, diarrhea are very common symptoms of most helminths that parasitize the digestive tract.
- Jaundice, liver and bile duct disorders, liver failure. These symptoms occur in helminths that affect the liver and bile ducts, as well as in malaria in the midst of the disease.
- Stomach pain.
- Intestinal obstruction due to closure of the intestinal lumen by a large number of roundworms or large flatworms.
All these symptoms of the presence of parasites in the human body, in the absence of data on other pathology, should prompt the doctor to consider a parasitic human disease and serve as a basis for diagnostic and laboratory tests.
Diagnosis of parasites in humans
Depending on the type of parasite that has invaded the human body, one or another test is performed. If we talk about external exoparasites, which are mainly insects, then the diagnosis of the disease is usually limited to a general examination, as well as microscopy of insects.
The general examination usually provides an accurate diagnosis and appropriate treatment or sanitation of the scalp or skin. In the case of demodicosis or scabies, the diagnosis can be easily established based on the location of the rash and the presence of itching.
In this case, scrapings made for microscopy confirm the diagnosis of intradermal parasites.
For gastrointestinal parasites, the main screening study (a diagnostic procedure that allows you to quickly and relatively informatively assess the presence or absence of the disease in a large number of people) is stool analysis.
- With a special microscopic examination of the stool, the laboratory assistant evaluates the presence of worm eggs, dead worms, cyst capsules and so on.
Through the morphology of helminth eggs, you can almost accurately determine the type of worm that parasitizes the body. Sometimes tapeworm segments are determined macroscopically in the faeces. They are then examined under a microscope to detect the appearance of a flatworm parasitizing the gastrointestinal tract.
In some cases, for example, when the diagnosis of parasites in the body is impossible by stool analysis or is not informative, immunological tests are used. They allow you to assess the presence of antibodies to a particular type of helminth. Unfortunately, due to the special immunological link between the human immune system and the parasite, the level of antibodies in some cases may not reflect the real picture of the disease.
In the case of malaria, a thick drop of blood is tested to detect Plasmodium malaria. The general blood picture, leukocyte levels, as well as all biochemical parameters of the blood, especially the liver, are also assessed.
The presence of elevated levels of eosinophils in the blood 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 radiographs, cystoscopy, FGDS, colonoscopy.
How to get rid of parasites in the human body?
The treatment of parasitic infections should be performed only by a doctor, following certain rules.
Self-medication and traditional medicine in such cases do not lead to improvement and can sometimes be fatal.
It is also important to provide preventative treatment for all family members and contacts.
Human exoparasites, which parasitize on hairy areas of the body, are destroyed with special disinfectants. Usually a single treatment followed by a hygienic wash is sufficient to kill the exoparasites.
When it comes to skin types of parasites (scabies, demodicosis), use special ointments containing insecticides against such organisms.
Anthelmintics are used against roundworms and flatworms, which act in the main lumen of the gastrointestinal tract specifically on helminths. Depending on the biological type of helminths, different treatment regimens are used (from one tablet to a series of courses).
Such drugs should be used strictly under the supervision of a physician to identify in a timely manner the negative effects and side effects of drugs.
No other treatment methods, detoxification programs, etc. can lead to the complete death of parasites in the body and as a result to cure a person.