To date, science knows about 280 species of worms that can develop and live in the human body, parasitizing on various organs and tissues. The frequency of human worm infection depends on the climatic and socio-economic conditions of specific territories (in underdeveloped countries, especially those in tropical and subtropical areas, the level of parasitic infections is much higher than in economically developed countries).
Ways of human infection with helminths
- Biohelminthiaza (infection from animals).
- Contagious helminthiasis (transmitted from person to person).
- Geohelminthiasis (diseases caused by parasites that carry out one of their life cycles on earth).
- The way the parasite enters the body;
- The degree of adaptation of the helminth to the human body;
- Population density (number) of parasitic individuals;
- Worm habitat (tissue parasites live in the soft tissue thickness, and luminal parasites live in the lumens of empty organs). Some helminths in different stages have luminal and tissue forms. The larval and developing stages of worms, as a rule, cause more pronounced pathological changes.
In the absence of re-infection, the number of adult parasites in the human body does not increase. This feature significantly distinguishes helminthic infestations from diseases caused by bacteria, viruses, fungi and protozoa.
Worms in humans: symptoms
Helminthiasis is a disease characterized by 2 stages of the course (acute, from two weeks to two months) and chronic (from several months to several years).
Symptoms of the acute phase of helminthiasis
The first signs of the disease can appear at different times (most often after 2-3 weeks, with ascariasis - after 2-3 days and with filariasis, the incubation period can last 6-18 months).
In the acute phase of parasitic invasion, the most characteristic symptom is an allergic reaction (antibodies are produced to the antigen of the larvae of migratory parasites). Often in people infected with worms, itchy rashes appear on the skin, prone to a recurrent course, regional lymph nodes, generalized or local edema, muscle and joint pain may occur. Also, the larvae of migratory parasites can cause chest pain, coughing, choking attacks, bowel movements, nausea and vomiting.
At the same time, the acute phase of helminthiasis can be associated with more serious disorders (severe forms of pneumonia, hepatitis, allergic myocarditis, hepatosplenomegaly (enlarged liver and spleen), meningoencephalitis).
The number of eosinophils in the blood increases (eosinophilia) and the normal quantitative ratio between protein fractions is disrupted (dysproteinemia).
Signs of chronic helminthiasisThe symptomatology of the chronic phase depends directly on which organ is "inhabited" by the parasites, as well as their size and number play an important role.
So when it parasitizes the intestines of single individuals, the disease can be asymptomatic (except in cases of infection with very large parasites). The characteristic signs of the chronic phase of intestinal helminthiasis are dyspeptic disorders. In children, asthenoneurotic and pain syndrome is more pronounced. With the massive invasion of roundworms, the development of intestinal blockage, obstructive jaundice and pancreatitis is possible.
By consuming all the substances necessary for their vital activity by the host body, the toxins cause digestive disorders, impaired absorption of vitamins, minerals, carbohydrates, proteins and fats. At the same time, the products of worm debris inhibit the normal intestinal microflora and reduce the body's immune forces.
In people suffering from helminthiases, due to a weakened immune system and an enhanced cell division process (as a result of continuous restoration of parasite-damaged tissue), the risk of malignant tumors increases significantly.
Types of helminths that parasitize the human body
The causative agents of human helminthiasis are 2 types of worms: roundworms (nematodes) and flatworms (tapeworms and lightning worms).
Round worms
Stake worm
The parasites that cause enterobiasis are small worms (up to 10 mm) with a thin cavity with a white-gray color. Infection occurs edible (through the mouth). The reason for this is dirty hands. The eggs of the parasite can be in the soil, in the fur of infected animals, unwashed vegetables and fruits, etc. At the same time, with enterobiasis, cases of self-infection are frequent (especially in children), resulting from scratching of the itchy areas and subsequent swallowing of eggs.
The worm larva develops within two weeks in the digestive tract. Once it has turned into an adult, the worm parasitizes the lower parts of the small and upper parts of the colon.
Even in the larval stage, the worm begins to damage the body of its host, producing enzymes that irritate the intestinal walls and lead to the development of an inflammatory process. Adult parasites attach to or penetrate the deeper layers of the intestinal mucosa, disrupting its integrity and contributing to the binding of a secondary bacterial infection. In the case of perforation of the small intestinal wall worms, peritonitis may develop. Also, due to irritation of intestinal receptors, motor and secretory functions of the gastrointestinal tract are disrupted, leading to the formation of gastroduodenitis, enteritis, etc. In childhood, long-term enterobiasis can cause nervous disorders and delayed physical development.
Ascaris
Ascaris is a large tail-shaped parasite, reddish-yellow in color, reaching 40 cm (female) and 15-25 cm (male) in adulthood. Without suction cups or other fixing devices, the roundworm is able to move independently towards food masses. Eggs laid by the female parasite are excreted along with the feces.
Infection with ascariasis occurs when ripe eggs are swallowed with water or unwashed vegetables and fruits. Once the eggs enter the intestine, the mature larvae emerge from them. Then, penetrating the intestinal wall, they reach the heart through the bloodstream, and from there enter the lungs. Through the pulmonary alveoli, the worm larva through the respiratory tract again enters the oral cavity. After repeated ingestion, the parasite reaches the small intestine, where it develops into an adult. The worm lives for 12 months, then dies and is excreted along with the feces. In the intestines of a host, one and several hundred individuals can live.
In the intestinal phase of their existence, roundworms, endowed with the ability to spiral motion, can penetrate even the narrowest openings. This characteristic of the parasite often leads to the development of quite serious complications (obstructive jaundice or pancreatitis). Allergens secreted by roundworms can provoke severe allergic reactions. A large number of adults can cause intestinal obstruction, and worms entering the respiratory tract sometimes cause choking.
Vlasoglav
Vlasoglav, the causative agent of trichocephalosis, is a white helminth that parasitizes in the initial part of the colon and reaches a size of 4-5 cm. The parasite feeds on blood and tissues of the rectal mucosa.Worm eggs laid by females on the intestinal wall come out along with the feces. Their development takes place in the environment (optimally in the soil). Eggs with parasite larvae mature in them enter the body through food, through dirty hands, with water or unwashed vegetables and fruits.
With a small number of worms, trichocephalosis is asymptomatic. In a severe stage (with massive invasion), the patient develops abdominal pain, develops severe diarrhea, sometimes accompanied by rectal prolapse. This condition is more common in debilitated children. With a moderate stage of trichocephaly, delayed child growth is possible.
Trichinella
The causative agent of trichinosis is a small round helminth that reaches 2-5 mm in length. Infection occurs when you eat poorly cooked meat (pork, bear, wild boar).
Penetrating into the intestines, the parasite larva matures in 3-4 days in the state of a sexually mature individual. The lifespan of the worm is 40 days, after which the parasite dies. By piercing the intestinal wall, the larvae enter the bloodstream and are carried to all organs of the human body, settling in the muscles. In this case, the respiratory and facial muscles, as well as the flexor muscles of the limbs, are affected more often.
In the first days after the invasion, patients complain of colic. Then, after about 2 weeks, the body temperature rises to 39-40 C, itchy rashes appear on the skin, muscle pain develops and the face swells. During this period, in case of mass infection, there is a considerable risk of death. After about a month, the patient recovers. The parasite encapsulates in a spiral shape, after which it dies within two years.
Circles and nectar
These two parasites are similar in biological characteristics as well as in diseases caused. In this regard, it is common to combine them under a common name (angworm). Worms, reaching a length of 10-15 mm, parasitize at 12-p. intestineIt should be noted that this is one of the most common parasites, but, at the same time, very rare. Worm larvae enter the human body through the skin after contact with contaminated soil. Further, entering the bloodstream, they, like roundworms, migrate to the lungs and then, through the bronchi, along with the expectorant saliva, to the digestive tract. Ankilostoma parasitizes in the intestine, attaching to the intestinal wall. The parasite, which feeds exclusively on blood, bites through blood vessels that penetrate the mucosa, injecting there an anticoagulant compound. On average, an adult can suck 0, 05-0, 35 ml of blood per day. Therefore, the most characteristic symptom of this helminthiasis is iron deficiency anemia, as well as a change in the ratio of protein fractions (dysproteinemia).
Flatworms
Wide bar
This is one of the largest helminths, reaching a length of 10-20 meters. The disease caused by this parasite is called difilobotriasis. The worm development cycle begins with freshwater fish or crustaceans. The larva enters the human body, which is the ultimate owner of the broadband, along with the infected fish eggs or fillets. Reaching the small intestine, the parasite clings to its wall and grows in a mature individual within 20-25 days.
Diphyllobothriasis occurs against the background of digestive tract disorders and B12 deficiency anemia.
Liver bundle
The parasite that causes opisthorchiasis is a flatworm that reaches a length of 7-20 mm. It should be noted that more than 50% of cases of hepatitis B infection (otherwise called cat) occur in residents of Russia. The parasite larvae begin to develop after the eggs enter the fresh water (from the snails that have swallowed them). Then they penetrate into the body of the fish (carp, carp, carp, roach). Human infection occurs when you eat contaminated fish meat that has not undergone sufficient heat treatment. The larva of hepatic fat from the small intestine penetrates the bile ducts and the gallbladder, being fixed there with the help of two suction cups.
In the acute stage of helminthiasis, the patient has soreness in the upper abdomen, body temperature rises, nausea develops, muscle aches, diarrhea and skin rashes are possible. The chronic course of opisthorchiasis is manifested by symptoms of hepatitis, inflammation of the bile ducts, cholecystitis, disorders of the digestive tract, nervous disorders, weakness and increased fatigue. The parasite leads to the development of irreversible changes, and even after its expulsion, the patient does not undergo chronic inflammatory processes and functional disorders.
Beef and pork ribs
These parasites, almost identical in structure, reach a length of 5-6 meters. Infection with teniarinosis and teniasis occurs due to consumption of meat from cattle or pork infected by the Finns (one of the intermediate forms of helminthiasis). Stable Finns, presented in the form of white bubbles reaching the size of 0, 5 cm, attach to the wall of the human small intestine and turn into an adult in 3 months. The tapeworm, consisting of more than 2000 segments, is constantly growing. In this case, the end segments, which contain eggs, break down and move independently along the colon to the anus, and then crawl out of the anus, or are released into the external environment along with the stool. The most characteristic symptoms of helminthiasis are disruption of the digestive tract.
Ekinokoku
For this parasite, a person is an intermediate host. The worm parasitizes the human body in the form of Finns. The ultimate owner of the echinococcus is a wolf, dog or cat. 
Infection occurs through contact with animals and environmental objects planted with Echinococcus eggs. Once inside the intestine, oncospheres (six-hook larvae) develop. From the intestines, they enter the bloodstream and are carried throughout the body.
The "favorite" parasitic sites of the worm are the liver and lungs. By settling on these organs, the larva turns into a Finn (echinococcal cyst), which, gradually increasing in size, begins to destroy nearby tissues. Often, echinococcosis in the diagnostic process is mistaken for a tumor of benign or malignant origin. In addition to mechanical impact (squeezing of organs and blood vessels), rupture of the echinococcal cyst sometimes occurs. This condition can cause toxic shock or the formation of numerous new cysts.
Alveokoku
This parasite, considered a type of echinococcus, is the cause of one of the most dangerous helminthiases (alveococcosis), which is similar in severity to cirrhosis and liver cancer. Infection occurs when oncospheres (eggs with mature larvae) enter the gut. There, the embryo leaves the egg and, penetrating the intestinal wall, enters the bloodstream. Further, with blood flow, the parasite spreads to all tissues and organs of the body (most often localized in the liver). Slowly where the main stage of development begins in the larvae (a multi-chamber bubble forms, laurocyst is formed). Each room contains the embryonic head of the parasite, which continues to develop gradually. Laurocysts are very aggressive formations that grow constantly due to the enlargement of bubbles, and also have the ability to grow in the liver, like cancer metastases. Necrotic changes due to disturbances in the functioning of blood vessels undergo necrotic changes in nearby tissues. Propagated in nearby structures, alveococcus forms fibrous nodules involving multi-chambered bubbles. This condition can last for several years, so it requires mandatory surgical intervention.
Diagnosis of helminthiasis
Diagnosing helminth infestations includes the following activities:
- a complete history taken, helping to discover possible causes of infection;
- laboratory tests of feces, blood, intestinal contents 12p, rectal and perianal mucus, muscle tissue, pulmonary saliva, bile. The analysis can detect eggs, segments or fragments of parasites. At the same time, an increased content of eosinophils in the blood is also a signal of the presence of helminthiasis.
- when diagnosing diseases caused by larval stages or tissue parasites, serological studies are performed (ELISA, RSK, indirect agglutination reaction, immunofluorescence analysis, etc. ). Ultrasound, CT and endoscopic examinations are prescribed to detect helminths affecting liver tissue.
Human worms: treatment
In the acute phase of a parasitic infection, the patient is prescribed detoxification and desensitization therapy. In severe cases of the disease (liver trematodes, trichinosis), glucocorticoids are used according to medical indications.
Specific anthelmintic chemotherapeutic agents are prescribed as specific therapy drugs, taking into account the nature of the pathogen.
In parallel, the patient is recommended to take antihistamines and enterosorbents. The final stage of treatment involves the use of probiotics that normalize the intestinal microflora.A special frugal diet is also prescribed (food should be digestible and low in fat).
During the period of antihelminthic therapy, the patient is required to strictly observe personal hygiene (to avoid re-infection). At the same time, for many helminths, all family members and persons who are in constant contact with the infected should undergo treatment.
Prevention of helminthiasis
- Maintaining personal and public hygiene;
- Strict adherence to cooking technology;
- Regular examination and preventive treatment of pets;
- Thorough washing of fresh vegetables, fruits and herbs;
- Proper treatment of river fish;
- Avoid eating raw, slightly salted and dry fish.