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Helminthiasis

worms in the human body

Helminthiasis- helminthic diseases caused by helminths - round and flat, less often ring and spiny parasitic worms.Helminthiasis is characterized by a chronic course and systemic effect on the body with the development of abdominal, allergic, anemic syndromes and chronic toxicosis;damage to the lungs, liver, bile ducts, brain and organs of vision.In the diagnosis of helminthic infections, laboratory (helminth-ovoscopic, helminth-larvoscopic, serological) and instrumental (x-ray, endoscopy, ultrasound, etc.) methods are used.Treatment of helminthic infection depends on the type of parasite and includes specific (anthelmintic) and pathogenetic therapy.

General information

Helminth infections are helminthic infestations caused by various types of lower parasitic worms - helminths.Helminthiasis has a chronic course, accompanied by exhaustion of the organism and reduction of its natural defenses.Enterobiosis, ascariasis, hookworm, trichuriasis and toxocariasis occupy leading positions in the structure of helminthiasis.

According to official statistics, the rate of infestation of the population of our country with helminthiasis is 1-2%, but in some regions it reaches 10% or more.The problem of increasing incidence of helminthiasis is relevant not only for infectious diseases, but also for pediatrics, therapy, surgery, gastroenterology, dermatology, allergology, urology and other practical medical fields.

Causes of helminthiasis

To date, more than 250 causative agents of helminthiasis in humans are known;The most common of them are about 50 species.Helminths that parasitize the human body are mainly represented by roundworms (class Nematoda) and flatworms (class flukes - Trematoda and tapeworms - Cestoidea);Less commonly, human infections occur with annelids (Annelida) and acanthocephala (Acanthocephala).Representatives of roundworms include pinworms, roundworms, trichinella, whipworms;tapeworms - beef, pig and dwarf tapeworms, echinococci, broad tapeworms;flukes - cat flukes and liver flukes.

The life cycle of helminths includes egg, larval and mature stages.Depending on the characteristics of the development of parasitic worms and the ways of infection, helminthic diseases are divided into biohelminthiasis, geohelminthosis and infectious (contact) helminthosis.

  1. Geohelminthsare most roundworms (nematodes).The stages of development of eggs and larvae of geohelminths take place in the soil under certain temperature and moisture conditions.Infection with geohelminthosis is caused by failure to maintain personal hygiene, consumption of water, fruit, vegetables contaminated with parasites or contact with soil contaminated with excrement.Geohelminthiasis includes helminthic diseases such as ascariasis, hookworm, trichuriasis, strongyloidiasis.
  2. To the numberbiohelminthsthey belong to flukes (trematodes) and tapeworms (cestodes), as well as some types of nematodes.To reach the invasive stage, they need to change one or two intermediate hosts, which can be fish, crustaceans, molluscs and insects.The causative agents of biohelminthiasis enter the human body by consuming meat or fish that has not been sufficiently thermally processed, or by drinking raw water.Representatives of biohelminthiasis are diphyllobothriasis, clonorchiasis, opisthorchiasis, taenia, taeniarhynchiasis, trichinosis, fascioliasis, echinococcosis.
  3. Kinfectious helminth infectionsbelong to invasions transmitted from person to person by personal contact, shared toiletries, dishes, underwear or self-infection.These are enterobiasis, hymenolepiiasis, strongyloidiasis, cysticercosis.

Classification

Helminth infections are classified depending on the biological characteristics of the helminths, the way they exist in the external environment, the routes of infection and the habitat in the human body.Taking into account the biological characteristics of pathogens, the following are distinguished:

  • nematodes(ascariasis, enterobiasis, trichuriasis, hookworm, nekatoriosis, etc.)
  • cestodiaze(taenia, cysticercosis, hymenolepiiasis, taeniarhynchiasis, echinococcosis)
  • trematodes(opisthorchiasis, clonorchiasis, schistosomiasis, fascioliasis).

Based on the mode of existence of parasitic worms in the environment, geohelminthosis, biohelminthosis and contact helminthosis are distinguished.Helminth infection can occur through food, water or percutaneously.Depending on the localization of the pathogen in the human body, helminth infections are divided into:

  • Intestinal.Human intestines are parasitized by causative agents of ascariasis, enterobiasis, hookworm, trichuriasis, strongyloidiasis, trichostrongyloidiasis, diphyllobothriasis, taenia, taeniarhynchosis, hymenolepiiasis, etc.
  • Extraintestinal.Extraintestinal helminths can live in the liver, gallbladder, blood vessels and subcutaneous tissue.Extraintestinal parasitosis includes filariasis, dracunculiasis, opisthorchiasis, schistosomiasis, fascioliasis, clonorchiasis, paragonimiasis, trichinosis, cystocercosis, etc.

In addition, according to the principle of localization, luminal (including intestinal) and tissue (skin and visceral) helminthiases are distinguished.

Symptoms of helminthiasis

The clinical picture of helminthiasis is very diverse and consists of a general reaction of the immune system as a response to parasite invasion and organ-specific lesions.During helminthiasis, there are acute or early phases (from 2-3 weeks to 2 months) and chronic phases (up to several years).The main pathological effects of helminths on the human body are toxic-allergic reactions, mechanical damage to organs and tissues, lack of nutrition and vitamins, and reduced immune capacity.

Acute phase

In the acute period of helminthiasis, the main manifestations are caused by the toxic-allergic effect of parasitic worms on the body.Patients present with fever, skin rash, muscle pain, and lymphadenopathy.Abdominal syndrome (dyspepsia, abdominal pain), pulmonary syndrome (dry cough, bronchospasm, difficulty breathing), hepatolienal syndrome (enlarged liver and spleen), asthenovegetative syndrome (apathy, fatigue, sleep disorders, irritability) often develop.

Chronic phase

In the chronic phase of helminthiasis, organ-specific lesions prevail, caused mainly by mechanical trauma at the site of helminth parasitism.Thus, the decisive factors in the course of intestinal helminthosis are dyspeptic disorders and abdominal pain.Violation of the absorption process in the intestines is accompanied by polyhypovitaminosis and progressive weight loss.Anemia due to iron deficiency is a frequent companion of intestinal helminthiasis.With a massive helminthic infestation, rectal prolapse, development of hemorrhagic colitis and intestinal obstruction are possible.

In the chronic phase of helminthosis, which occurs with primary damage to the hepatobiliary system, obstructive jaundice, hepatitis, cholecystitis, cholangitis and pancreatitis can occur.In the case of migration of pinworms during enterobiasis, the development of persistent vaginitis, endometritis and salpingitis is possible.

The chronic stage of strongyloidiasis occurs with the formation of ulcers on the stomach and duodenum.Trichinosis can affect the cardiovascular system (myocarditis, heart failure), respiratory organs (bronchitis, bronchopneumonia) and the central nervous system (meningoencephalitis, encephalomyelitis).Due to the invasion of lymphatic vessels by filariasis, filariasis often develops lymphangitis, lymphedema of the extremities with swelling of the mammary glands and genitals.With echonococcosis, liver and lung cysts form, and when they suppurate, complications in the form of purulent peritonitis or pleurisy are possible.

Against the background of helminthiasis in children and adults, the effectiveness of preventive vaccination and revaccination decreases, which is why the necessary protective level of immunity is not achieved.In the presence of accompanying diseases, helminthiases modify and worsen their course.The outcome of helminthiasis can be recovery (by natural death or expulsion of the helminth) or residual phenomena, often with disabling consequences.

Diagnostics

Based on clinical and epidemiological data, helminth infections are mostly diagnosed in the chronic stage.To identify the causative agent of helminthiasis, special laboratory methods are used: microhelminthoscopy (scraping for enterobiasis), helminth-ovoscopic (examination of feces for worm eggs), helminth-larvoscopic, serological (ELISA, RIF, RSK, RNGA), his st.Test material for detecting eggs, larvae or fragments of mature helminths can be feces, vomit, duodenal contents, sputum, urine, blood, skin biopsies, etc.

For intestinal helminthiasis, skin allergy tests with helminth antigens can be informative.In order to identify and assess the severity of organ-specific lesions, instrumental diagnostics are widely used: ultrasound of the liver, pancreas, FGDS, colonoscopy, endoscopic biopsy, radiography and CT of internal organs, liver scintigraphy.

intestinal worms

Treatment of helminthiasis

A holistic approach to the treatment of helminth infections consists of etiotropic and syndromic therapy.Specific treatment includes the prescription of anthelmintic drugs, taking into account the type of helminth and the stage of invasion.The effectiveness of deworming is evaluated based on the results of a repeated parasitological examination.The following groups of drugs are used for etiotropic therapy of helminthiasis:

  • antinematode
  • anticestodiasis
  • anti-trematode
  • broad-spectrum drugs.

Antibacterial drugs, enterosorbents, enzymes, probiotics, etc. are added to the main treatment for intestinal helminthosis.Symptomatic therapy for helminthosis may include prescribing antihistamines, intravenous infusions, vitamins, cardiac glycosides, NSAIDs, and glucocorticoids.For echinococcosis, the main method of treating patients is surgery (cyst/liver abscess surgery, echinococcotomy).

Prevention

Prevention of geohelminthiasis is carried out through hygiene education of the population, protection of the environment from fecal pollution and instilling in children the rules of personal hygiene.In the prevention of the spread of biohelminthosis, an important role is played by the deworming of domestic animals, veterinary-sanitary supervision over the sale of meat products, and careful heat treatment of meat and fish.In the prevention of contact helminthiasis, the main importance is breaking the mechanism of transmission of pathogens in organized, mostly children's, groups.It is recommended to carry out seasonal medicinal prevention of helminthosis in families (for example, albendazole), regular parasitological examinations of children and risk groups.