Helminths

Helminthiasis, or diseases caused by helminths, are among the most common in humans. According to rough estimates by experts from the World Health Organization, one in four people on the planet is infected with one or another of the helminths. And this is not surprising, because you can get this infection almost anywhere in the world. Doctors equate the incidence of helminthiasis with the spread of influenza and ARVIs.

Doctors estimate the extent of infection with worms in our country at 270 cases per 100, 000 inhabitants, but the actual incidence, according to experts, is several times higher. This is due to the fact that often a person does not even notice that an uninvited guest has settled in his body. If helminths do not manifest themselves in any way, the disease can go undiagnosed for decades.

Everything about helminths

Parasites, helminths or worms?

This vast group of living beings has several names at once. First of all, we are talking about parasites, that is, living organisms that live at the expense of others. In addition, we are talking about endoparasites, that is, living inside another organism - in its tissues and organs. Finally, we are talking about worm-like creatures, which are ideally suited to live for a long time in the body of an infected animal and reproduce efficiently.

As a result, helminths are parasitic worms. The very term "helminth" was once introduced by Hippocrates. Among the people, these nasty creatures are also called worms - from the ancient Greek word, simply meaning a parasitic worm.

So, speaking of helminths, we won't go wrong in calling them worms or worms parasites. And if we are talking about helminthiasis, these diseases can also be called "parasitic infections".

A variety of helminths in humans

In total, scientists know about 287 types of helminths that can parasitize humans. In our country, only 65 species have been identified, and only 24 species are among the most common.

Helminths in humans live throughout the body, and each species has its own preferences.

Basically, worms prefer the gastrointestinal tract and mainly the small intestine, in which you can find roundworms, pinworms, three varieties of tapeworms, broad tapeworms, hookworms, etc. Vlasoglav alone occupies the large intestine.

In the liver, more precisely in its bile ducts, as well as in the gallbladder, we can find fluids, opisthorchis, etc. . The lung fluke settles in the lungs. Trichinella affects the muscles. The adult pig tapeworm lives in the small intestine and its larvae (cysticerci) can be found in the eyes and central nervous system. Schistosomes (tropical helminths) prefer the veins of the gastrointestinal tract and genitourinary system.

Heartworms are usually ubiquitous - they can be found in the lymphatic system and in closed body cavities - in the retroperitoneal space, in the pericardial sac, and their larvae are usually found in the blood or in the skin.

Types of helminths that live in humans

Helminths, the types of which are most interesting to doctors, are divided into two main types: flat and round (nematodes). The classification is based on the cross section of the body of the worm: in roundworms it has the shape of a circle, and in tapeworms it is flattened in the direction of the conditional back to the conditional abdomen. Tapeworms are divided into two classes: fluke (trematodes) and tapeworm (cestodes).

• Nematodes. Most nematodes are inhabitants of the human intestine. This group includes roundworms, pinworms, Trichinella, whipworms, etc. , very different in size from each other - from a few millimeters to 1. 5 meters. They all have their own well-developed digestive systems. Nematodes have both males and females. It is not difficult to distinguish them in adults: females are usually twice the size, and besides, in males, the "tail" is twisted towards "the abdomen".
• Trematodes. The body of trematodes resembles a leaf or a lancet and cannot be compared in size to other helminths: they are small worms, from a few millimeters to 3. 5-5. 5 cm long. Unlike roundworms, trematodes have a pair of suction cups in the mouth and abdomen. Their digestive system is in its infancy. A significant part of the species in this group are hermaphrodites, that is, they combine the characteristics of both sexes. The exception is schistosomes, which have both males and females.
• Cestodes. Cestodes are worms, which are a long strip fragmented into short segments, at one end of which is a head with hooks and suckers. These worms live exclusively in the small intestine - their whole body does not fit into any other organ. And this is not surprising, because the length of tapeworms can reach 10-11 meters. They don't need a digestive system at all because they absorb everything they need from the food a person eats. All tapeworms are hermaphrodites.

The organism in which the helminths in the larval stage live is called the intermediate host (these can be animals, fish, molluscs and, of course, humans), and the carrier of the adult forms is called the final host. .

Depending on whether or not a given type of worm has a stage of development in the body of an intermediate host, we also speak of bio- and soil-transmitted helminthiasis.

• Soil-transmitted helminths do not have such a scene. The eggs of the worms fall into the ground, where they wait until, by the will of fate, they are introduced into the body of the future owner. Soil-transmitted helminths include whipworms, roundworms, hookworms, etc.
• Biohelminths have such a stage and there can be several hosts. Examples include Trichinella, tapeworms, schistosomes, all tapeworms, etc.

Some scientists now distinguish, by the mechanism of transmission, a third group of worms - contagious helminths, which include pinworms (soil-transmitted helminths) and dwarf tapeworms (biohelminths). These parasites are spread through contact with an infected person.

In addition, according to the hosts that play a key role in the life of helminths, anthroponoses and zoonoses are isolated.

• The first category includes helminthiasis, in which a person is an obligatory stage of his life cycle: ascariasis, enterobiasis, etc.
• Zoonoses include helminthiasis, the causative agents of which can successfully exist without anyone, but at the same time our species is also susceptible to it, and if infection occurs, the worms will not interfere with life and prosperity. This category includes opisthorchiasis, diphyllobothriasis, etc.

How does helminth infection occur?

Most often people get infected with worms, so to speak, orally, that is, by swallowing helminth eggs. The most prominent example is pinworm, the eggs of which a child can collect in a sandbox (a means of spreading infection through household contact). The alimentary pathway (through food) is characteristic of roundworms - through contaminated vegetables or fruits and trematodes that enter the body when consuming contaminated but poorly heat-treated seafood or meat, etc.

However, food is not the only route of infection with helminths. Eggs can enter the human body by inhaling dust. And hookworms and schistosomes enter the body through the skin - and they're called contagious worms, and the route of infection is percutaneous. And since schistosoma can be caught while swimming in a pond, this route of infection is also called aquatic.

In the tropics, the filamentous plant lives, it is also the wuchereria, which is propagated with the help of a mosquito bite. And it is a route of transmission of vector-borne infection.

Helminth infection can also occur through contact with infected animals - cats and dogs. Usually people catch roundworms (toxocar, etc. ) and animal tapeworms. Pets, in the process of licking each other, carry helminth eggs through their fur. A person who petted such an animal and did not wash their hands immediately afterwards, risks injecting an infection into their mouth. Another option for worm infestations is to clean the litter box without gloves.

How do helminths affect the body?

Mechanical impact

This category includes all actions of helminths in which the integrity of the host's tissues is violated. For example, adult helminths with hooks and suction cups attach themselves with their help, while damaging the gastrointestinal mucosa. As a result, erosion of tissues develops in the area of localization of the worm, ulcers are formed, and the nutritional processes of the mucous membrane are disturbed, which can even lead to its death (necrosis).

As they move around the body, the so-called migratory larvae can also cause hemorrhages and inflammation in damaged areas, making it easier for them to enter tissues. And helminths in the intestines often provoke the development of appendicitis, intestinal obstruction and even its rupture.

Finally, the cysticercus, which has entered the brain and is actively developing there, compresses the tissue, which can lead to the death of a person.

Host malnutrition

First, the helminths themselves "steal" from their host, consuming the food they have eaten. Secondly, some human helminths feed themselves on blood - this is what hookworms and whipworms do, or they take the substances necessary for hematopoiesis. Therefore, against the background of a parasitic infection, anemia can develop.

With prolonged chronic infection with helminths, which absorb metabolically valuable nutrients, protein-calorie deficiency is diagnosed.

Poisoning of the human body with helminth toxins

Metabolic products of whipworm and tapeworm destroy erythrocytes, and roundworm secretions cause capillary expansion and, as a result, hemorrhages.

Some parasitic worms begin to represent an increased danger after death, releasing substances with necrotic and hemotoxic properties.

Allergy to helminth proteins

Helminths are foreign organisms for us, therefore our body perceives many proteins secreted by them (during vital activity or after death) as a potential danger and may regard them as antigens. During sensitization to these antigens, antibodies are formed - immunoglobulins IgE and IgG-4. These antibodies, in contact with mast cells, basophils and eosinophils, cause their destruction. At the same time, there is a release of substances that trigger allergic reactions (allergy mediators) - histamine, serotonin, heparin, etc.

Suppression of the body's defenses

The negative effect of helminths on the body can be indirect. Tapeworms, located, as mentioned above, in the small intestine, can cause a decrease in gastric acidity. And this significantly reduces the protection against the ingress of pathogenic bacteria into the body.

Many helminths have immunosuppressive abilities, that is, they suppress the body's defenses, thereby ensuring a comfortable existence for a long time. It is an evolutionary adaptation acquired by them during adaptation to a tightly defined host circle. But suppression of the human immune system leads to increased vulnerability to other infections and diseases.

Cancer risks

Some chronic helminthiasis dramatically increase the risk of cancer. Parasites in the course of their vital activity destroy tissues and organs and thus cause the development of malignant tumors in this place. Cancer often develops against the background of opisthorchiasis, schistosomiasis, clonorchiasis, etc.

Phases of the evolution of helminthiasis

What are the signs of helminthiasis? Once the worms have entered the body, the symptoms of infection depend on the phase of the disease.

During helminthiasis, there are 4 main phases:

• Acute (early) phase of helminthiasis. At this point, the causative agent of infection enters the human body, which leads to sensitization of the body to the proteins of the helminth. The first symptoms of helminths appear 2-4 weeks after infection. Usually during this period allergic-type reactions develop - itchy rashes, conjunctivitis, cough, swollen lymph nodes, inflammatory processes in the joints, analyzes show an increased concentration of eosinophils, etc.
• Latent phase (latent). At this stage, the helminth develops to an adult state and is finally determined with a permanent place of dwelling, after which the helminthiasis passes to a chronic stage.
• Chronic (late) phase. At this stage, adult helminths actively reproduce, producing tens and hundreds of thousands of eggs and larvae, which enter the external environment or spread to other organs of the body. Helminths in children can cause muscle cramps, seizures - epileptics, hysterics, etc. Doctors note that all of these signs of helminthiasis are nonspecific and resemble the symptoms of dozens of other diseases, so it is impossible to diagnose them. More precisely, there are several helminths, the symptoms of which are very characteristic, but even they should be checked with the help of several tests.
• Exodus phase. This term refers to either the complete recovery of the patient or his disability against the background of complications of helminthiasis. These include malignant tumors in opisthorchiasis and schistosomiasis, cirrhosis of the liver, etc.

Helminths: symptoms of infection

How the helminth invasion (the invasion of helminths in one's body) will affect the human body is determined by many factors: the method of penetration, the extent of the infection, the duration of the disease andthe lifespan of the helminth, the characteristics of its cycle of nutrition and development.

In general, doctors distinguish the following symptoms of helminth infection, in the presence of which you need to see a doctor and undergo an examination:

• periodic frequent nausea and vomiting, abdominal pain;
• frequent allergies;
• sleep disturbances, chronic fatigue, irritability;
• itching in the anal area;
• frequent urinary tract infections;
• chronic gastrointestinal diseases, dysbiosis;
• symptoms of chronic intoxication of the body: frequent colds, blue circles under the eyes, pallor, enlarged lymph nodes;
• vulvovaginitis;
• an increased level of eosinophils in the results of a blood test;
• stunted growth and weight.

The question arises: if the helminths have settled in the body, will the symptoms of the infection be visible immediately or only after some time? Are there helminths that are difficult to detect for signs of infection? Doctors point out that with a non-intensive invasion, the first symptoms of helminthiasis can appear within a month, or two, and after a few years. That is, during this time, no signs of helminth infection will be visible.

Manifestations of helminthic infection in children

Helminths are more common in children than in adults. This is due to a lack of hygiene skills, as well as close contact with the environment, which can be a source of helminth eggs. Such an environment can be a sandbox in a playground, beds in a grandmother's dacha, someone else's toy played by an infected child, etc.

What complaints are most often recorded when children are infected with intestinal nematodes:

• dysfunction of the gastrointestinal tract - 75% of children;
• allergic reactions - 71%;
• sleep disturbances - 54%;
• appetite disorders - 44%;
• pain in the abdomen - 40%;
• itching in the anal area - 36%.

Less often, against the background of helminth infection, children developed immune disorders (19%) and bruxism, that is, grinding of teeth (16%). It is a paradox, but these two symptoms are generally regarded by the population as signs of helminths.

Diagnosis of helminthiasis

What are the tests for helminths?

It should be understood that the analysis of helminths alone is not enough. None of the existing methods of detecting parasitic worms can in itself serve as a basis for a definitive diagnosis. According to doctors, in some cases a positive result can only be obtained for the 8th to 10th time! The reasons can be multiple: the females lay eggs at different intervals which do not coincide with the times of collection, the samples of biomaterials turned out to be empty, because taken in the wrong place, the disease was in such a phase that it wasdetermined by which methods were selected almost impossible, etc.

The most common types of analysis for helminths are the study of feces for helminth eggs, perianal scraping, analysis of duodenal contents, analysis of biomaterials of the patient's lungs, blood test forhelminths, etc.

Less often, urine is required for diagnosis (schistosomiasis of the genitourinary system, enterobiasis), a study is carried out for helminths of the patient's muscles (trichinosis) with a sample of material by a method of biopsy.

How is feces tested for helminth eggs?

For the analysis of helminths, 50 g of feces from the patient is sufficient (approximately 1 tbsp). Today in the pharmacy you can buy a special clean container for testing, where you will need to collect the feces for helminth eggs. It is best to return the sample to the laboratory on the same day (for strongylosis and hookworm infection - no later than 4 hours after collection). If necessary, you can store a stool sample for helminths no more than a day at a temperature of 0-4 ° C, it is absolutely impossible to freeze it. In principle, it is possible to use special preservatives which allow the samples to be preserved for up to several months.

Perianal scraping - analysis of helminth eggs

Perianal scraping is used to diagnose helminthiasis such as enterobiasis, tapeworm, tapeworm, etc. Unlike the stool test for helminths, the scraping material is collected from the skin around the anus using a cotton swab, wooden spatula, glass sticks or tape. adhesive. The procedure for collecting material for the analysis of helminth eggs is carried out in the early morning, and the patient should not wash in the evening or in the morning.

An important point: even repeated analysis of helminths in this way does not guarantee the reliability of the result in case of enterobiasis. Female pinworms lay eggs at regular intervals and if you don't catch the "right time" you can rest assured that there are no eggs - there are no worms.

Analysis of duodenal content (bile)

Bile collection is performed using an empty gastric tube. As this method is invasive (unlike methods such as faeces for helminth eggs, urine collection, and perianal scratching), it is only prescribed for strict indications when there is a reasonable suspicion ofspecific helminthiasis. The bile is examined for strongyloids and hookworm larvae, and individual portions of bile are also analyzed for the presence of helminth eggs that live in the pancreas and hepatic ducts.

Blood test for helminths

In addition to the above methods, there are also so-called serological methods for the diagnosis of helminthiasis. In this case, a blood test is carried out for helminths, more precisely for antibodies to them.

The main serological method today is enzyme-linked immunosorbent assay (ELISA), which is distinguished by high specificity and the highest sensitivity (90%) among all other methods. That is, it allows you to determine with enough accuracy what type of helminths a person is infected with, and allows you to detect them, even if there are very few. ELISA reliability is 60%. ELISA is extremely relevant for the detection of tissue helminthiasis, in which the worms parasitize the interior of the patient's organs and tissues (trichinosis, toxocariasis).

Instrumental methods of diagnosing helminths

It is far from always possible to detect helminths using the above laboratory diagnostic methods, including using immunoassay methods. Some parasitic worms have a dense capsule that is resistant to outside influences. They can also hide in tissues that are to some extent protected from inflammatory reactions in the body - such as the spinal cord. Some types of worms have their own means of protection - antienzymes. These sexually reproducing worms exchange genetic information. Given the rapidity of their reproduction and the renewal of generations, it is not surprising that these helminths over time become less vulnerable to the means of detecting and treating parasitic infections.

If the analysis of feces for helminths, blood and other methods did not give an effect, in this case, these parasites can be detected with the help of instrumental diagnostic methods - X-rays, ultrasound, computed tomography, etc. tissues of the liver and spleen, enlarged lymph nodes in them, well, in some cases - echinococci, large clusters-tangles of intestinal worms - you can see the parasites themselves.

Treatment of helminthiasis

Traditional medicine, through trial and error, has discovered a number of plants with deworming properties: aspen, pumpkin, chamomile, tansy, male fern, etc. effect:

• cucurbitin (pumpkin seeds);
• annual artemisinin wormwood);
• ascaridol (ragweed);
• santonin (citrine wormwood);
• thymol (thyme);
• pelletierine (pomegranate root);
• carvacrol (oregano, thyme, bergamot);
• diospirol (persimmon);
• arecoline (areca palm);
• pyrethrins (Dalmatian chamomile);
• tremulacin (aspen);
• nicotine (tobacco) and its isomer anabazine (tobacco and leafless barnyard);
• emetine (emetic root).

And today, a considerable part of anthelmintic drugs contain the same active substances that once provided the anthelmintic effect in decoctions and tinctures.

conclusions

• Helminthiasis is one of the most common diseases in the world. Anyone in their environment with a 100% probability has people and animals infected with helminths.
• But if the number of individuals in the body is small, and the body itself is generally healthy, the disease can be asymptomatic for many years, without manifesting itself in any way.
• Even a regular medical exam every 3 years or tests once a year does not guarantee that a person really does not have helminths.
• The signs of worms in the body can be very similar to the symptoms of other diseases. Therefore, if the treatment of intestinal diseases and other similar pathologies for some reason does not help you persistently, you should consider taking tests for helminths.
• According to the results of an analysis for helminths, the diagnosis of helminthiasis is not made, since false positive and false negative results are possible. You should not try to independently submit to a random examination - it is better to consult a doctor: based on the totality of symptoms, nutritional data and travel data, he will select tests that will allow you tofind out exactly whether a person has helminths or not.
• You cannot independently prescribe helminth pills. A remedy for worms can have contraindications for a particular patient and cause serious harm if misused.