Helminthiasis

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

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Helminthiases are human, animal and plant diseases caused by parasitic worms (helminths).

Causes of helminthiasis

Currently, more than 70 species of 250 helminths known to be parasites of the human body are found in our country.The most common are roundworms (roundworms, pinworms, trichinella, whipworms), tapeworms (pig, cattle and dwarf tapeworms, broad tapeworms, echinococcus), and worms (liver and cat worms).

Helminths are characterized by developmental stages: egg → larva → sexually mature form.

Infection with helminths most often occurs after their eggs and/or larvae enter the body.Depending on the mechanism of infection and the route of transmission, helminthiasis is divided into: geohelminthiasis, biohelminthiasis and contact helminthiasis.Geohelminths develop without an intermediate host, biohelminths develop with a sequential change of one, two or three hosts, contact helminths are transmitted by contact.

Pig tapeworms, cattle tapeworms, echinococcus and other types of worms develop with successive changes of one, two or three hosts.Intermediate hosts can be fish, molluscs, crustaceans, and insects.A person becomes infected with these helminths by eating food that has not undergone complete heat treatment:

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

Whipworms, roundworms, hookworms, and necators develop without an intermediate host.The eggs and larval form of this parasite enter the soil with feces.If the rules of personal hygiene are not followed, it penetrates the body of the new host.

Through contact - that is, through personal contact between a healthy person and an infected person, through the use of shared utensils, toiletries, linen, and through inhalation of dust in the room where the infected person is - enterobiasis (pathogen - pinworm) and hymenolepiasis (pathogen - dwarf tapeworm) are spread.In the case of enterobiasis, self-infection often occurs.

Certain types of helminths are parasites in certain organs, causing various helminthiasis:

• in the large intestine - pork, cattle, dwarf tapeworms, nematodes (hookworms, roundworms, strongyloides), pinworms, whipworms.From the intestinal lumen, pig tapeworm larvae can enter the bloodstream and spread throughout the body, settling in fat tissue, muscle vessels, eye chambers, and brain;
• in the liver and bile ducts - trematodes (opisthorchis, clonorchis, fasciola).Echinococcal cysts are mainly located in the liver, and after rupture, daughter blisters can be found in the mesentery, peritoneal lining, spleen and other organs;
• in the respiratory organs - echinococci, alveococci, pulmonary flukes, causing paragonimiasis;
• in the nervous system - schistosomiasis, paragonimiasis, echinococcosis and alveococcosis;
• in the organs of vision - oncocerciasis, loiasis, complicated forms of taeniasis;
• in the circulatory system - necatoriasis, schistosomiasis, diphyllobothriasis;
• in the lymphatic system - filariasis, trichinosis;
• in skin and subcutaneous tissue - hookworm, oncocerciasis, loiasis, larval stage of schistosomiasis;
• in the skeletal system - echinococcosis;
• in skeletal muscle - trichinosis, cysticercosis of muscle tissue.

The lifespan of helminths in the body of the definitive host can vary, depending on the type of parasite and ranges from a few weeks (pinworms) to a few years (tapeworms) and a few decades (fasciola).

Classification of diseases

There are two types of worms that become parasites in humans:

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

Depending on the route of spread of parasites and their biological characteristics, they are distinguished:

• biohelminthiases;
• geohelminthiases;
• contact helminth infection.

Symptoms of helminthiasis

Helminths have different effects on the human body:

• the effect of antigens, when local and general allergic reactions develop;
• toxic effects (excreta products of helminths cause malaise, weakness, dyspeptic symptoms);
• traumatic effect (when the parasite attaches to the intestinal wall, the blood supply is interrupted with subsequent necrosis and atrophy of the mucous membrane; the absorption process may be disturbed; mechanical compression of the tissue by helminths);
• secondary inflammation as a result of bacterial penetration following migrating helminth larvae;
• violation of metabolic processes;
• as a result of absorption of blood by some helminths, anemia occurs;
• neuro-reflex effect - irritation of nerve endings by helminths causes bronchospasm, intestinal dysfunction, etc.;
• psychogenic effects, manifested by neurotic conditions, sleep disorders;
• immunosuppressive effect.

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

In the initial acute stage, helminths most often have not released their eggs, sensitization of the body occurs (production of antibodies, release of inflammatory mediators, increased permeability of vascular walls) and traumatization of the organs where the larvae migrate.Clinical symptoms may not be present, but in some cases the disease can occur with clear clinical manifestations.The acute stage lasts from 1 to 4 months, sometimes 8-10 months or more.

Complaints from patients in the acute stage:

• temperature increase from several days to two months (low-grade fever or above 38ºС, accompanied by chills, severe weakness and sweating);
• recurring itchy skin rash;
• local or general edema;
• regional lymph node enlargement;
• pain in muscles and joints;
• cough, asthma attack, chest pain, prolonged catarrhal symptoms, bronchitis, tracheitis, symptoms resembling pneumonia, asthma syndrome, hemoptysis;
• stomach ache, nausea, vomiting, stool disorder.

At the end of this stage of helminth infection, the acute allergic phenomenon gradually subsides, and the clinic of the chronic stage has not yet had time to develop.

The acute stage becomes subacute when the "young" helminth gradually matures.Then comes the chronic stage, corresponding to the development of the parasite into a sexually mature individual.The clinical picture develops against the background of toxic effects of helminth waste products, traumatic effects of helminths on organs (shellworms, trichuriasis, etc.), mechanical effects (echinococcal cysts in the liver grow, compressing neighboring organs; cysticerci - in the brain), secondary inflammatory processes (duodenitis is observed in strong metabolic disorders (duodenitis is observed), or strong metabolic disorders. stomach and duodenum, secondary immune deficiency, etc.

Symptoms depend on the organ in which the helminths are parasitic, their size and quantity.

Forintestinal helminthiasesThe following syndromes are characteristic:

• dyspeptic (stomach discomfort, feeling full after eating, early fullness, flatulence, nausea);
• painful;
• asthenoneurotic (extreme fatigue, increased nervous excitability and irritability).

Enterobiasis is characterized by perianal itching at night.With massive attacks by roundworms, there may be intestinal obstruction, pancreatitis, obstructive jaundice.

Intestinal cestodes(taeniarrhoz, diphyllobothriasis, hymenolepiasis, taeniasis and others) are without symptoms or with a small number of symptoms (with symptoms of dyspepsia, pain, anemia).

Liver trematodes(fascioliasis, opisthorchiasis, clonorchiasis) causes:

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

Hookworm diseasemanifested 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 schistosomiasismanifested by the appearance of blood at the 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 severe consequences.

For diseases caused by parasitism of migrating larvaezoohelminthswhen a person is not the natural host, distinguish between skin and visceral forms.The skin form is caused by the penetration of certain animal helminths under the human skin: waterfowl schistosomatids (trematodes), hookworms of dogs and cats, strongylids (nematodes).When a person comes into contact with soil or water, helminth larvae penetrate the skin.There is burning, tingling or itching at the site of helminth introduction.There may be a short-term fever and signs of general malaise.After 1-2 weeks (less often 5-6 weeks) recovery occurs.

The visceral form develops due to ingestion of helminth eggs with water and food.At the beginning of the disease there may be discomfort, allergic exanthema (skin rash).In the human intestine, larvae hatch from helminth eggs, penetrate the intestinal wall into the blood, reach the internal organs, where they grow and reach a diameter of 5-10 cm, compressing the tissue and disrupting the function of the organ.When tapeworm larvae (cysticerci, tsenura) are located in the membranes and brain matter, headaches, signs of cerebral hypertension, paresis and paralysis, and epileptiform seizures are observed.Larvae can also be located in the spinal cord, eyeball, serous membrane, intermuscular connective tissue, etc.

The result of helminthiasis can be 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 established based on a combination of complaints, information received from the patient about the course of the disease, data from the 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 tests: general analysis, leukoformula, ESR (with blood smear microscopy in the presence of pathological changes);
• biochemical blood tests:
• total protein, albumin, protein fraction; 
• assessment of kidney function indicators (urea, creatinine, glomerular filtration);
• assessment of liver function indicators (bilirubin, ALT, AST, alkaline phosphatase);
• pancreatic alpha-amylase;
• assessment 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, rectum and perianal mucus.

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

• Stool analysis for helminth eggs.
• Test for enterobiasis (worm eggs), smear.
• Microscopic examination of feces to detect eggs of enterobiasis pathogen Enterobius vermicularis (pinworms).
• Test for enterobiasis (worm eggs), spatula.
• Analysis is necessary if there is a suspicion of pinworm infection, as well as during hospitalization and registration of medical records.
• Analysis for kindergarten and school.

The children's examination program is intended to be completed before entering kindergarten or school.The results of this study are necessary to obtain a medical certificate according to form 026U approved by the Ministry of Health of the Russian Federation.

Conduct immunological studies - determination of specific antibodies to helminths:

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

Tests aimed at detecting IgG antibodies to the causative agent of strongyloidiasis are used for early serological diagnosis of strongyloidiasis in cases of clinical suspicion (eosinophilia, serpentine skin lesions, pulmonary or gastrointestinal symptoms) of this disease.

In difficult cases, the following studies may be recommended:

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

Which doctor should I contact?

If you suspect helminthiasis, you should consult a therapist or general practitioner, and with your child, see 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 helminthiasis, regardless of severity, and patients with severe and complicated diseases are treated in the hospital.

Therapy is carried out with anthelmintic drugs.The frequency of administration and dosage of the drug depends on the age and weight of the patient and is 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 allergic reactions 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 helminthiases

Preventive measures aimed at preventing helminth infections include:

• compliance with personal hygiene rules (use of individual towels, personal hygiene items and other accessories for daily use);
• use only high quality water in daily life;
• regular vaccination and deworming of pets;
• Wash vegetables, fruits, berries before use;
• adequate heat treatment for meat and fish products.

With regular contact with pets, children in groups of children, contact with the earth, hobbies of fishing or hunting, frequent trips to exotic countries, prevention can be done through the use of medicines.Drug prophylaxis must be taken by the whole family 2 times a year (for example, in spring and autumn).

IMPORTANT!

The information in this section should not be used for self-diagnosis and self-treatment.In case of pain or exacerbation of other diseases, diagnostic tests should be prescribed only by the attending physician.To make a diagnosis and prescribe treatment correctly, you should contact your doctor.