Helminthiasis

Helminthiasis (helminthic infestation): causes, symptoms, diagnosis and methods of treatment.

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Helminthiasis are diseases of humans, animals and plants caused by parasitic worms (helminths).

Causes of helminthiasis

Currently, in our country there are more than 70 species out of the known 250 helminths that parasitize the human body.The most common are roundworms (roundworms, pinworms, trichinella, whipworm), tapeworms (pig, beef and dwarf tapeworm, broad tapeworm, echinococcus) and flukes (liver flukes and cat flukes).

Helminths are characterized by stages of development: eggs → larvae → sexually mature forms.

Infection with helminths most often occurs after their eggs and/or larvae enter the body.Depending on the mechanism of infection and transmission routes, helminth infections are divided into: geohelminth infections, biohelminth infections and contact helminth infections.Geohelminths develop without intermediate hosts, biohelminths develop with successive changes of one, two or three hosts, contact helminths are transmitted by contact.

Pig tapeworm, beef tapeworm, echinococcus and other types of worms develop by successively changing one, two or three hosts.Intermediate hosts can be fish, molluscs, crustaceans and insects.A person becomes infected with these helminths if he eats food that has not undergone complete heat treatment:

• beef infected with beef tapeworm larvae;
• pork affected by Finnish pork tapeworm;
• lightly salted and raw fish with opisthorchis or broad tapeworm larvae;
• raw water or vegetables and fruits treated with this water.

Whipworm, roundworm, hookworm and nekator develop without intermediate hosts.Eggs and larval forms of these parasites enter the soil with feces.If the rules of personal hygiene are not observed, they penetrate into the body of the new host.

Enterobiasis (causing agent - pinworm) and hymenolepiasis (causing agent - dwarf tapeworm) are transmitted through contact - i.e. personal contact between a healthy person and an infected person, using shared utensils, toiletries, bedding, and breathing in dust in the room where the infected person is. In the case of enterobiosis, self-infection often occurs.

Helminths of certain species parasitize in certain organs, causing various helminthosis:

• in the large intestine - pork, beef, dwarf tapeworms, nematodes (hookworms, roundworms, strongyloids), pinworms, whipworms.From the intestinal lumen, pig tapeworm larvae can enter the bloodstream and spread throughout the body, settling in adipose tissue, muscle vessels, eye chambers and brain;
• in the liver and bile ducts - trematodes (opistorchis, clonorchis, fasciola).Echinococcal cysts are primarily found in the liver, and after their rupture, daughter cysts can be found in the mesentery, peritoneal layers, spleen and other organs;
• in the respiratory organs - echinococci, alveococci, lung flukes, causing paragonimiasis;
• in the nervous system - schistosomiasis, paragonimiasis, echinococcosis and alveococcosis;
• in the organs of vision - oncocerciasis, loiasis, complicated forms of teeniasis;
• in the circulatory system - nekatoriasis, schistosomiasis, diphyllobothriasis;
• in the lymphatic system - filariasis, trichinosis;
• in skin and subcutaneous tissue - hookworm, onchocerciasis, loyiasis, larval stage of schistosomiasis;
• in the skeletal system - echinococcosis;
• in skeletal muscles - trichinosis, cysticercosis of muscle tissue.

The life span of helminths in the body of the final host can be different, it depends on the type of parasite and ranges from a few weeks (pinworms) to a few years (bandworms) and decades (fasciola).

Classification of diseases

There are two types of worms that parasitize humans:

• Nemathelminthes – roundworms, class Nematoda;
• Plathelminthes are flatworms, which include the classes Cestoidea - tapeworms, Trematoda - the class of flukes.

Depending on the ways of spread of parasites and the characteristics of their biology, they differ:

• biohelminthiasis;
• geohelminthiasis;
• contact infections with helminths.

Symptoms of helminthosis

Helminths have different effects on the human body:

• antigenic effects, when local and general allergic reactions develop;
• toxic effect (waste products of helminths cause weakness, weakness, dyspeptic symptoms);
• traumatic effect (when parasites are fixed on the intestinal wall, the blood supply is disturbed by necrosis and subsequent atrophy of the mucous membrane; absorption processes may be disturbed; mechanical tissue compression by helminths);
• secondary inflammation as a result of bacterial penetration after migrating helminth larvae;
• violation of metabolic processes;
• as a result of blood absorption by some helminths, anemia occurs;
• neuro-reflex effect - irritation of nerve endings by helminths causes bronchospasm, intestinal dysfunction, etc.;
• psychogenic effect, which manifests itself in neurotic states, sleep disorders;
• immunosuppressive effect.

Helminthiasis is characterized by stages of development.Each stage is characterized by its own clinical symptoms.

In the initial acute phase, helminths usually do not yet release eggs, sensitization of the organism occurs (production of antibodies, release of inflammatory mediators, increased permeability of the vascular wall) and traumatization of the organs through which the larvae migrate.Clinical symptoms may be absent, but in some cases the disease may occur with pronounced clinical manifestations.The acute phase lasts from 1 to 4 months, sometimes 8-10 months or more.

Complaints of patients in the acute phase:

• elevated temperature from several days to two months (low-grade fever or above 38ºС, accompanied by shivering, severe weakness and sweating);
• recurrent itchy skin rashes;
• local or generalized edema;
• enlargement of regional lymph nodes;
• pain in muscles and joints;
• cough, asthma attacks, chest pain, prolonged catarrhal symptoms, bronchitis, tracheitis, symptoms simulating pneumonia, asthmatic syndrome, hemoptysis;
• abdominal pain, nausea, vomiting, stool disorder.

At the end of this phase of helminth infection, acute allergic phenomena gradually subside, and the clinic of the chronic phase has not yet had time to develop.

The acute phase becomes subacute when the "young" helminths gradually mature.Then comes the chronic phase, which corresponds to the development of the parasite into sexually mature individuals.The clinical picture develops against the background of the toxic effect of waste products of helminths, the traumatic effect of helminths on organs (ankylostosis, trichuriasis, etc.), mechanical effects (echinococcal cyst in the liver grows, compresses neighboring organs; cysticeri - in the brain), secondary inflammatory process in the brain is a secondary inflammatory process (severe metabolic disease).disorders (hypo- or avitaminosis), functional disorders of the stomach and duodenum, secondary immunodeficiencies, etc.

Symptoms depend on the organs in which the helminths parasitize, their size and quantity.

Forintestinal helminthiasisThe following syndromes are characteristic:

• dyspepsia (stomach discomfort, feeling of fullness after eating, early satiety, flatulence, nausea);
• painful;
• asthenoneurotic (feeling of extreme fatigue, increased nervous irritability and irritability).

Enterobiasis is characterized by nocturnal perianal itching.With a massive roundworm infestation, intestinal obstruction, pancreatitis, and obstructive jaundice can occur.

Intestinal cestodes(teeniarhynchosis, diphyllobothriasis, hymenolepiasis, taeniasis, etc.) are asymptomatic or with a small number of symptoms (with symptoms of dyspepsia, pain, anemia).

Trematodes of the liver(fascioliasis, opisthorchiasis, clonorchiasis) cause:

• chronic pancreatitis;
• hepatitis;
• cholecystocholangitis;
• neurological disorders.

Hookworm diseaseit is manifested by asthenovegetative syndrome (weakness, fatigue, pale skin) due to the development of iron deficiency anemia.

Filariasis is characterized by an allergic syndrome of varying severity and regional lymphadenitis.

Urogenital schistomiasisit is manifested by the appearance of blood at the very end of urination, frequent urge to urinate, pain during urination.

Alveococcosis, cysticercosis, echinococcosismay remain asymptomatic for a long time.At a later stage, suppuration or rupture of cysts containing parasites leads to anaphylactic shock, peritonitis, pleurisy and other serious consequences.

For diseases caused by parasitism of migratory larvaezoohelminthswhen the person is not the natural host, distinguish cutaneous and visceral forms.The skin form is caused by the penetration of certain animal helminths under the human skin: schistosomatids of waterfowl (trematodes), hookworms of dogs and cats, strongylids (nematodes).When a person comes into contact with soil or water, helminth larvae penetrate the skin.At the site of introduction of helminths there is a sensation of stinging, burning or itching.A short-term fever and signs of general weakness may occur.After 1-2 weeks (rarely 5-6 weeks) recovery occurs.

The visceral form develops as a result of ingestion of helminth eggs with water and food.At the beginning of the disease, malaise, allergic exanthema (rash on the skin) may occur.In the human intestines, the larvae hatch from helminth eggs, penetrate through the intestinal wall into the blood, reach the internal organs, where they grow and reach 5-10 cm in diameter, compress the tissues and disturb the function of the organs.When tapeworm larvae (cysticerci, cenura) are found in the membranes and matter of the brain, headache, signs of cerebral hypertension, paresis and paralysis, and epileptiform convulsions are observed.Larvae can also be found in the spinal cord, eyeball, serous membranes, intermuscular connective tissue, etc.

The outcome of helminthiasis can be a complete recovery with the elimination of helminths or the development of irreversible changes in the host's body.

Diagnosis of helminthiasis

The diagnosis of helminthiasis is made based on a combination of complaints, information obtained from the patient about the course of the disease, data from laboratory and instrumental examination methods.

In the acute phase of helminth infection, there is a blood reaction to the presence of helminths in the body, therefore the following studies are recommended:

• clinical blood test: general analysis, leukoformula, ESR (with a blood smear microscope in the presence of pathological changes);
• biochemical blood test:
• total proteins, albumin, protein fractions; 
• assessment of kidney function indicators (urea, creatinine, glomerular filtration);
• assessment of liver function indicators (bilirubin, ALT, AST, alkaline phosphatase);
• pancreatic alpha-amylase;
• evaluation of carbohydrate metabolism: glucose (in blood), glucose tolerance test with determination of glucose in venous blood on an empty stomach and after exercise after 2 hours.

The following biological materials can be examined for the presence of helminths: feces, blood, urine, duodenal contents, bile, sputum, muscle tissue, rectal and perianal mucus.

Since helminths are not excreted in feces at any stage of development, it is recommended to give feces three times - every 3-4 days.

• Fecal analysis for helminth eggs.
• Test for enterobia (pinworm eggs), smear.
• Microscopic examination of stool to detect eggs of enterobiasis pathogen Enterobius vermicularis (pinworms).
• Test for enterobiosis (pinworm eggs), spatula.
• Analysis is necessary if pinworm infection is suspected, as well as during hospitalization and registration of the medical record.
• Analyzes for kindergarten and school.

Children's examination program should be completed before starting kindergarten or school.The results of these studies are necessary for obtaining a medical certificate in accordance with form 026U approved by the Ministry of Health of the Russian Federation.

Conduct immunological studies - determination of specific antibodies to helminths:

• roundworm IgG antibodies;
• anti-Echinococcus IgG;
• IgG antibodies to Toxocar antigens;
• Anti-Opisthorchis felineus IgG (IgG class antibodies to cat fluke antigens);
• IgG antibodies to trichinella antigens;
• antibodies to the causative agent of anisakiasis (nematodes from the genus Anisakis), IgG;
• antibodies to the causative agent of clonorchiasis, IgG;
• Antibodies to Strongyloides stercoralis, the causative agent of strongyloidiasis, IgG.

The test for detection of IgG antibodies to the causative agent of strongyloidiasis is used for early serological diagnosis of strongyloidiasis in cases of clinical suspicion (eosinophilia, serpentine skin lesions, pulmonary or gastrointestinal symptoms) of this disease.

In severe cases, the following studies may be recommended:

• plain x-ray of chest organs;
• comprehensive ultrasound examination of abdominal organs (liver, gall bladder, pancreas, spleen);
• CT scan of the abdominal cavity and retroperitoneum;
• CT of the chest and mediastinum;
• CT of the brain and skull.

Which doctors should I contact?

If you suspect helminthiasis, you should consult a therapist or general practitioner, and the child should also consult a pediatrician.

If there are indications for surgical treatment, the patient is referred to a surgeon.

Treatment of helminthiasis

Most people with helminth infections do not require hospitalization.Patients with tissue helminthosis, regardless of severity, and patients with a severe and complicated course of the disease are treated in the hospital.

Therapy is carried out with anthelmintic drugs.The frequency of application and dosage of the drug depend on the age and body weight of the patient and are determined by the doctor.

Desensitization, detoxification therapy and vitamin therapy may be indicated.To reduce the temperature, non-steroidal anti-inflammatory drugs are prescribed, for an allergic reaction and itching - antihistamines, for severe edema - diuretics.In severe cases, hormonal drugs are needed.

The presence of helminths in organs and tissues may be an indication for surgical treatment.

Complications

• Bronchial asthma.
• Pneumonia.
• Bowel cancer.
• Cirrhosis.
• Portal hypertension.
• Gastrointestinal bleeding.
• Ascites.
• Hepatitis.
• Liver abscess.
• Peritonitis.
• Allergic myocarditis.
• Meningoencephalitis.
• Chronic glomerulonephritis.
• Chronic kidney disease.
• Disorders of hemostasis.
• Loss of vision.

Prevention of helminthiasis

Preventive measures aimed at preventing helminth infection include:

• compliance with the rules of personal hygiene (use of an individual towel, personal hygiene products and other accessories for daily use);
• use only quality water in everyday life;
• regular vaccination and deworming of pets;
• Thorough washing of vegetables, fruits, and berries before consumption;
• sufficient thermal processing of meat and fish products.

Regular contact with pets, children in children's groups, contact with the earth, hobbies of fishing or hunting, frequent trips to exotic countries, prevention can be carried out with the use of medicines.Prophylaxis with drugs must be taken by the whole family 2 times a year (for example, in spring and autumn).

IMPORTANT!

The information in this section cannot be used for self-diagnosis and self-treatment.In case of pain or other aggravation of the disease, diagnostic tests should be prescribed only by a doctor.To diagnose and properly prescribe treatment, consult your doctor.