Worms in humans: photos, symptoms, treatment
- Ways of human infection with helminths
- Factors affecting the manifestation of helminthiases
- Worms in humans: symptoms
- Types of helminths parasitizing in the human body
- Diagnosis of helminthiases
- Worms in humans: treatment
- Prevention of helminthiases
To date, science knows about 280 species of worms that can develop and live in the human body, parasitizing in various organs and tissues. The frequency of infection with human worms depends on the climatic and socio-economic conditions of specific areas (in the underdeveloped countries, especially those located in the tropical and subtropical zone, the level of parasitic infections is much higher than in economically developed countries). According to statistics, only in Russia, which is the habitat of 20 species of worms capable of parasitizing humans, about 15 million people are infected each year, of which 80% are children.
Ways of human infection with helminths
- Biohelminthiases (infection from animals).
- Contagious helminthiases (transmitted from person to person).
- Geohelminthoses (diseases caused by parasites that conduct one of the life cycles in the earth).
Factors affecting the manifestation of helminthiases
- Method of penetration of the parasite into the body;
- The degree of adaptation of helminth to the human body;
- Population density (number) of parasitizing individuals;
- The habitat of the worm (tissue parasites live in the thickness of soft tissues, and lumens live in the gaps of hollow organs). Some helminths in different phases have both luminal and tissue forms. Larval and developing stages of worms, as a rule, cause more pronounced pathological changes.
In the absence of repeated infection, the number of adult parasites in the human body does not increase. This feature significantly distinguishes worm 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 helminthiosis
The first signs of the disease can occur at different times (usually 2-3 weeks, with ascariasis - after 2-3 days, and with filariasis, the incubation period can last 6-18 months).
In the acute stage of parasitic infestation, the most characteristic symptom is an allergic reaction (antibodies develop to antigens of migrating parasitic larvae). Often, people infected with worms have itchy rashes on the skin, prone to recurrent course, regional lymph nodes increase, generalized or local edema, muscle and joint pain may occur. Also, migratory parasite larvae can cause pain in the chest, cough, asthma attacks, stool disorders, nausea and vomiting.
At the same time, the acute phase of helminthiosis may be accompanied by more serious disorders (severe forms of pneumonia, hepatitis, allergic myocarditis, hepatosplenomegaly (enlargement of the liver and spleen), meningoencephalitis).
The amount of eosinophils (eosinophilia) increases in the blood and the normal quantitative ratio between protein fractions (dysproteinemia) is disrupted.
Symptoms of chronic helminthiasis
The symptomatology of the chronic phase directly depends on which organ is "populated" by parasites, and their size and quantity play an important role.
Thus, with parasitization in the intestine of individual individuals, the disease can be asymptomatic (except for cases of infection with very large parasites). Characteristic signs of the chronic phase of intestinal helminthiases are dyspeptic disorders. Children are more pronounced asthenoneurotic and painful syndrome. With massive invasion of ascarids, it is possible to develop intestinal obstruction, mechanical jaundice and pancreatitis .
Consuming all the substances necessary for its vital activity from the host's body, helminths cause digestive disorders, impaired absorption of vitamins, minerals, carbohydrates, proteins and fats. At the same time, the products of the vital activity of the worms inhibit the normal intestinal microflora and reduce the body's immune forces.
In people suffering from helminthiasis, due to weakened immunity and the enhanced process of cell division (the effects of the permanent restoration of parasite-damaged tissues), the risk of malignant tumors increases significantly.
Types of helminths parasitizing in the human body
The causative agents of human helminthiasis are 2 types of worms: round (nematodes) and flat (tape and fluke).
Parasites that cause enterobiosis are small (up to 10 mm) thin cavitary worms that have a grayish-white color. Infection occurs by alimentary route (through the mouth). The reason is dirty hands. Eggs of the parasite can be found in the ground, on the wool of infected animals, unwashed vegetables and fruits, etc. At the same time, when enterobiosis, cases of self-infection (especially in children) that occur as a result of scratching the itching areas and subsequent ingestion of eggs are not uncommon. The larva of the pinworm develops for two weeks in the digestive tract. Turned into an adult, the worm parasitizes the lower parts of the small and upper parts of the large intestine.
Even in the larval stage, the pinworm starts to damage the host organism, producing enzymes that irritate the intestinal walls and lead to the development of the inflammatory process. Adult parasites, suck or penetrate deeper layers of the intestinal mucosa, disrupting its integrity and facilitating the attachment of a secondary bacterial infection. If the pinworms perforate the small intestine wall, peritonitis may develop. Also, due to irritation of the intestinal receptors, the motor and secretory functions of the gastrointestinal tract, leading to the formation of gastroduodenitis, enteritis, etc., are disturbed. In childhood, the long-term current enterobiosis can cause nervous breakdowns and a backlog in physical development.
Ascariidae is a large parasite of spindle-shaped red-yellow color, reaching in its adult state 40 cm (females) and 15-25 cm (males). Not having suckers or other attachments, the ascarid is able to move independently towards the food masses. Eggs, laid by a female parasite, are excreted together with feces.
Infection with ascariasis occurs in the case of ingestion of mature eggs with water or unwashed vegetables and fruits on which there are soil particles. After penetration of eggs into the intestine, ripened larvae emerge from them. Then, penetrating into the wall of the intestine, they reach the heart by the bloodstream, and from there they enter the lungs. Through the pulmonary alveoli, the larva of the ascaris along the respiratory tract again penetrates into the oral cavity. After repeated swallowing, 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 intestine of one host, one or several hundred individuals can live.
In the intestinal phase of its existence, ascarids, endowed with the ability to spiral movements, can penetrate even the narrowest openings. This feature of the parasite often leads to the development of quite serious complications (mechanical jaundice or pancreatitis). Allergens released by ascarids can provoke severe allergic reactions. A large number of adults can cause intestinal obstruction, and worms that enter the respiratory tract sometimes cause suffocation.
Vlasoglav, the causative agent of trichocephalosis, is a white helminth parasite in the initial section of the large intestine and reaches a size of 4-5 cm. The parasite feeds on blood and tissues of the rectal mucosa.
The eggs of the vagal head, laid by the female on the walls of the intestine, go out together with the feces. Their development occurs in the environment (optimally - in the soil). Eggs with parasite larvae matured in them penetrate into the body alimentary way, through dirty hands, with water or unwashed vegetables and fruits.
With small amounts of worms, trichocephalus is asymptomatic. In a severe stage (with massive invasion), the patient has abdominal pain, develops severe diarrhea, sometimes accompanied by prolapse of the rectum. This condition is most often observed in weakened children. At an average phase of a trichocephalosis the delay of growth of the child is possible.
The causative agent of trichinosis is a small round helminth, reaching 2-5 mm in length. Infection occurs when eating poorly roasted meat (pork, bear, boar). Penetrating into the intestine, the larva of the parasite ripens to the state of the sexually mature individual within 3-4 days. The life span of the worm is 40 days, after which the parasite dies. By probing 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 flexor muscles of the limbs, are most often affected.
In the first days after the invasion, patients complain of abdominal pain. Then, after about 2 weeks, the body temperature rises to 39-40 C, the skin appears itchy rashes, muscle pain develops, the face swells. In this period, in case of massive infection, there is a significant risk of death. Approximately one month later, recovery comes. The parasite is encapsulated in a spiral form, after which it dies within two years.
Ankylostoma and nectar
These two parasites are similar among themselves on biological grounds, as well as on the caused diseases. Due to this, they are usually united under a common name (hookworm). Worms reaching a length of 10-15 mm, parasitize in 12-p. Gut. It should be noted that this is one of the most common, but at the same time, rarely detected parasites. Larvae of worms penetrate the human body through the skin on contact with infected soil. Further, getting into the bloodstream, they, just like roundworms, migrate into the lungs, and then, through the bronchi together with expectorating sputum - into the digestive tract. Ankylostoma parasitizes in the intestine, attaching to the intestinal wall. The parasite, which feeds exclusively on blood, bites the blood vessels through the mucous membrane, injecting an anticoagulant component into it. Over the course of a day, an adult can on average absorb 0.05-0.35 ml of blood. Therefore, the most characteristic symptom of this helminthiasis is iron deficiency anemia, as well as a change in the ratio of protein fractions (dysproteinemia).
This is one of the largest helminths, reaching a length of 10-20 meters. The disease caused by this parasite is called diphyllobothriasis. The cycle of development of the worm begins with freshwater fish or crustaceans. In the human body, which is the final owner of a wide ribbon, the larvae enter with caviar or infected fish fillets. Reaching the small intestine, the parasite attaches to its wall and within 20-25 days grows to a mature individual.
Diphyllobothriasis occurs against the background of disturbances in the digestive tract and B12 deficiency anemia.
The parasite that causes opisthorchiasis is a flat worm, reaching a length of 7-20 mm. It should be noted that more than 50% of cases of infection with the hepatic trematode (also called a cat's fluke) are among the inhabitants of Russia. The larvae of the parasite begin to develop after the eggs get into the fresh water (from the snails that swallowed them). Further they penetrate into the body of the fish (carp, crucian carp, bream, roach). Infection occurs when eating contaminated fish meat, which has not undergone sufficient heat treatment. The larva of the hepatic trematode from the small intestine penetrates into the bile ducts and into the gallbladder, being fixed there with the help of two suckers.
In the acute phase of helminthiosis, the patient has soreness in the upper abdomen, body temperature rises, nausea, muscle pain, diarrhea, skin rashes. The chronic course of opisthorchiasis is manifested by symptoms of hepatitis, inflammation of the bile ducts, cholecystitis, digestive tract disorders, 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.
Bovine and Pork Chain
These parasites, almost identical in structure, reach a length of 5-6 meters. Infection with tenierhynchosis and shadows is due to the consumption of meat of cattle or pork, infected with Finns (one of the intermediate forms of helminthiosis). Viable Finns, represented in the form of whitish vesicles, reaching a size of 0.5 cm, attach to the wall of the small intestine of a person and for 3 months turn into an adult. The ribbon parasite, consisting of more than 2000 segments, is constantly growing. In this case, the terminal segments containing eggs are torn off and move independently along the colon to the anus, and then creep out of the anus, or are excreted into the external environment along with feces. The most characteristic symptoms of helminthiasis are disruption of the digestive tract.
For a given parasite, a person is an intermediate host. The worm parasitizes in the human body in the form of a Finn. The ultimate owner of echinococcus is a wolf, a dog or a cat. Infection occurs alimentary in contact with animals and with environmental objects, seeded echinococcus eggs. After entering the intestine, they develop oncospheres (six-larva). From the intestine they penetrate into the bloodstream and are carried throughout the body.
The "favorite" places of worm parasitization are the liver and lungs. Settling in these organs, the larva turns into a Finn (echinococcal cyst), which, gradually increasing in size, begins to destroy nearby tissues. Often, echinococcosis during the diagnosis is mistaken for a tumor of benign or malignant origin. In addition to mechanical impact (squeezing organs and blood vessels), sometimes there is a rupture of the echinococcal cyst. This condition can cause toxic shock or the formation of multiple new cysts.
This parasite, considered a kind 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 penetrating oncospheres (eggs with matured larvae) into the intestine. There the fetus emerges from the egg and, penetrating into the intestinal walls, penetrates into the bloodstream. Further, with a blood stream, the parasite spreads across all tissues and organs of the body (most often localized in the liver). It is there that the larvae begin the main stage of development (a multi-chambered bubble, a bay-cyst) is formed. Each chamber contains the germinal head of the parasite, which continues to develop gradually. Lavrozists are very aggressive formations, constantly growing at the expense of increasing vesicles, and also having the ability to germinate into the liver, like cancer metastases. The nearby tissues due to disruption of the blood vessels are subjected to necrotic changes. Spreading on nearby structures, alveococcus forms fibrous nodes with inclusions of multi-chambered blisters. This condition can last for several years, in connection with which it requires mandatory surgical intervention.
Diagnosis of helminthiases
Diagnosis of helminthic invasions includes the following measures:
- Careful collection of anamnesis, which helps to find out possible causes of infection;
- Laboratory studies of feces, blood, contents of 12p intestine, rectal and perianal mucus, muscle tissue, pulmonary sputum, bile. Eggs, segments or fragments of parasites can be detected during the analysis. However, the increased content of eosinophils in the blood is also a signal about the presence of helminthiosis.
- In the diagnosis of diseases caused by larval stages or tissue parasites, serological tests are performed (ELISA, DSC, indirect agglutination reaction, immunofluorescence analysis, etc.).
- Ultrasonography, CT and endoscopic examinations are used to identify helminths that damage the liver tissue.
Worms in humans: treatment
In the acute phase of parasitic infection, the patient is prescribed detoxification and desensitizing therapy. In severe cases (liver trematodes, trichinosis), glucocorticoids are used for medical reasons.
As specific therapy drugs, taking into account the nature of the pathogen, special anthelmintic chemotherapeutic agents are prescribed.
In parallel, the patient is recommended taking antihistamines and enterosorbents. The final stage of treatment includes the use of probiotics, which normalize the intestinal microflora.
Also, a special gentle diet is prescribed (food should be easily digestible and contain few fats).
During anthelminthic therapy, the patient must strictly observe personal hygiene (to avoid re-infection). At the same time with many helminthiases, all members of the family and those who are with the infected person in constant contact must undergo treatment.
Prevention of helminthiases
- Compliance with personal and public hygiene;
- Strict adherence to the technology of cooking;
- Regular examination and preventive treatment of domestic animals;
- Careful washing of fresh vegetables, fruits and greens;
- Proper processing of river fish;
- Refuse to consume raw, slightly salted and dried fish.
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