Parasites in biology are considered to be those organisms that carry out their vital activity at the expense of another organism of another biological species.
Such vital activity of the parasite does not bring any benefit to the host organism and, at best, 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, the parasite escapes to the external environment or joint death.
Parasitic diseases of humans have been known practically since the primitive era of human existence. This fact was established in the process of observing the behavior of man's immediate ancestors - monkeys. The parasites that inhabit the wool are detected by the monkeys and moved away from each other. This process has a very important character in social interaction.
Human intolerance to the appearance of acne and holes in the skin also has its origins in the first era of human existence. Some insect parasites in tropical areas can lay their larvae in the skin. This leads to a reflex need to squeeze them out of the skin.
Various worms affecting the eyes, skin and gastrointestinal tract have been described by ancient scientists. In the 18-19th century, with the development and introduction of microscopy into medical practice, scientists established the causes and modes of transmission of parasites that can cause specific diseases in humans.
- The beginning of the twentieth century and the discovery of anti-parasitic agents have enabled humanity to cope with most parasitic diseases.
Hence, humanity coexists very closely with various parasites for most of its history. However, modern medical science makes it possible to diagnose the entire 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 for patients.
The primary care physician will help identify parasites in the human body, symptoms and treatment. Sometimes infectious disease specialists from a narrower specialty may be involved - parasitologists.
What are parasitic diseases?
Parasitic diseases are nosologies that arise after the introduction (invasion) of biological agents into the body. The latter are referred to the group of human parasites. The symptomatology of such diseases is extremely diverse and depends precisely on the agent that has taken root and carries 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 the parasite's waste products 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. An increase in 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 intestinal intussusceptions (more often in children) or the development of a bowel obstruction.
- Parasites living inside a person can cause sensitization and non-specific allergic reactions.
- Microparasites can disrupt the functioning of blood cells, causing fever and intoxication.
- 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 variety of negative effects of parasites that arise in the body is due to different biological species that are introduced into human organs. However, such a biological diversity of parasites living in the human body has allowed doctors to identify specific signs of parasitic diseases.
Parasites living in the human body
The main routes of human parasite infection depend on the life cycle of the biological organism, which is the causative agent of the parasitic disease.
Doctors identify the ways the parasite penetrates a person as:
- Path of the contact.It is characteristic of insect exoparasites, as well as some helminths that live mainly in water, the larvae of which penetrate under the human skin. You can get infected in this way both from a sick person and through contaminated linen, bedding, personal or public hygiene items, and so on.
- Fecal-oral routeof infection. It occurs when cysts of the pathogen enter food after contact with infected feces, mainly from animals. Self-invasion can also be observed - self-infection of a person if personal hygiene is not observed, and so on.
- Contamination.The pathogen enters the bloodstream when infected insects are crushed.
- Transmissive infection.The parasite enters the bloodstream when bitten by an insect carrying the disease. Most often, this route of transmission is typical of the simplest parasites, for example, malaria.
- Sexually transmitted infection.It is characteristic for both venereal diseases caused by parasites and for some helminths that can affect the urinary tract and genitals of a person.
Protozoa, helminths (round and flat worms), insects and some types of fungi are attributed to the causes of parasitic diseases.
The presence of man with these species depends on the geographical and climatic area. Therefore, each country's medicine keeps its own registries and a list of parasites specific to it.
The biological organisms that enter the human body have been studied in detail by both medical biologists and doctors, which made it possible to clearly classify all biological species that can cause parasitic diseases:
- The simplest organisms (amoebiasis, balantidiasis, babeosis, Chagas disease, leishmaniasis, malaria, giardiasis, trypanosomiasis, toxoplasmosis, trichomoniasis).
- Helminths. The term worms is sometimes used (ascariasis, dichroceliosis, diphyllobothriasis, dranculosis, clonorchiasis, opisthorchiasis, strongyloidiasis, teniasis, fascioliasis, schistosomiasis, enterobiasis, echinococcosis).
- Exoparasites (louse (pubic, head, clothes), demodicosis, fleas, insects, scabies).
Signs of parasites in the human body
Unfortunately, there are no exact signs of parasites in the human body and no symptoms that indicate this or that type of parasitic infection. This leads to the fact that for an accurate diagnosis, for example, helminthiasis, specific tests are required.
On the other hand, almost all exo-infections are diagnosed very simply, based on the clinical picture and the presence of a certain type of insect on the skin.
In general terms, 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 and others). An itchy, acne-like rash is often associated with a condition such as demodicosis (a special type of tick).
- 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.
- Pain in the lungs, cough with phlegm (this situation may be typical for the migration of ascaris larvae into the lungs, as well as with echinococcal cysts of the lungs, and so on)
- Nausea, vomiting and diarrhea are very common symptoms of most helminths that parasitize in the digestive tract.
- Jaundice, liver and biliary tract disorders, liver failure. These symptoms occur with helminths affecting the liver and biliary tract, as well as with malaria at the height of the disease.
- Stomach pain.
- Intestinal obstruction due to the closure of the intestinal lumen with a large number of nematodes or large representatives of flatworms.
All these symptoms of the presence of parasites in the human body, in the absence of data for another pathology, should lead the doctor to think about a parasitic human disease and serve as a basis for diagnostic and laboratory studies.
Diagnosis of parasites in humans
Depending on the type of parasite that has invaded the human body, one or another research is performed. If we talk about external exoparasites, which are mainly insects, the diagnosis of the disease is usually limited to a general examination and microscopy of the insects.
General examination usually provides an accurate diagnosis and appropriate treatment or sanitation of the scalp or skin. In case of demodicosis or scabies, the diagnosis can be easily established based on the location of the rash and the presence of itching.
The fragments taken for microscopy in this case confirm the diagnosis of intradermal parasites.
For gastrointestinal parasites, the main screening study (a diagnostic procedure that allows you to quickly and relatively informatively evaluate data on the presence or absence of the disease in a large number of people) is the analysis of stool.
- With a special microscopic examination of feces, the laboratory assistant evaluates the presence of worm eggs, dead helminths, cyst capsules, and so on.
Based on the morphology of helminth eggs, you can almost accurately determine the type of worm that parasitizes in the body. Sometimes in the stool, the segments of the tapeworm are determined macroscopically. They are then examined under a microscope to establish the appearance of a flat worm that parasites in the gastrointestinal tract.
In some cases, for example, when the diagnosis of parasites in the body is impossible by analyzing the feces or is not informative, immunological studies are used. They allow you to assess the presence of antibodies against a particular type of helminth. Unfortunately, due to the special immunological relationship between the human immune system and the parasite, the level of antibodies in some cases may not reflect the true picture of the disease.
In case of malaria, a thick drop of blood is tested to detect Plasmodium malaria. In addition, the general blood count, leukocyte levels and all biochemical parameters of the blood, especially the liver, are evaluated.
The presence of an increase in the level of eosinophils in the blood is a frequent 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 X-rays with contrast media, cystoscopy, FGDS, colonoscopy.
How to get rid of parasites in the human body?
Treatment of parasitic infections should only be carried out by a doctor, subject to certain rules.
Self-medication and traditional medicine in these cases do not lead to improvement and can sometimes be fatal.
It is also important to provide preventive treatment to 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 enough to kill the exoparasites.
When it comes to types of skin parasites (scabies, demodectic mange), special ointments containing insecticides against such organisms are used.
Anthelmintics are used against round and flat worms, which act in the main lumen of the gastrointestinal tract specifically on helminths. Depending on the biological type of helminths, various treatment regimens are used (from one tablet to a series of courses).
Such drugs should be used strictly under the supervision of a physician in order to promptly recognize the negative effects and side effects of drugs.
No other methods of treatment, detoxification program, and so on can lead to the complete death of parasites in the body and, consequently, to the cure of a person.