Helminthiasis

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

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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 of the 250 known helminths that parasitize the human body.The most common are roundworms (roundworms, pinworms, trichinella, whipworms), tapeworms (pig, bovine and dwarf tapeworms, broad tapeworm, echinococcus) and flukes (liver fluke and cats).

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

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

Pig tapeworm, bovine tapeworm, echinococcus and other types of worms develop with a successive change 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 worm;
• lightly salted and raw fish with opisthorchis larvae or broad band;
• raw water or vegetables and fruits treated with this water.

Whipworm, roundworm, hookworm and nekator develop without intermediate hosts.The 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 a new host.

By contact - that is, through personal contact between a healthy person and an infected person, through the use of shared dishes, toilets, linens and through inhalation of dust in a room where an infected person is - enterobiasis (pathogen - pink tapeworm) and hymenolepiasis (pathogen - dwarf tapeworm) are transmitted.In the case of enterobiasis, self-infection often occurs.

Helminths of a certain type parasitize in certain organs, causing various helminthiasis:

• in the large intestine - pig worms, cattle, dwarf tapeworms, nematodes (hookworms, roundworms, strinkyloides), breast worms, whipworms.From the lumen of the intestines, the larvae of the pig worm can enter the bloodstream and spread throughout the body, settling in fatty tissues, muscle vessels, eye and brain chambers;
• in the liver and biliary tract - trematodes (opisthorchis, clonorchis, fasciola).Echinococcal cysts are mainly located in the liver and after their rupture, daughter bubbles can be found in the mesentery, peritoneal layers, 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 - onchocerciasis, loiasis, complicated forms of taeniasis;
• in the circulatory system - nekatoriasis, schistosomiasis, difilobothriasis;
• in the lymphatic system - filariasis, trichinosis;
• on skin and subcutaneous tissue - breast worm, onchocerciasis, loiasis, larval stage of schistosomiasis;
• in the skeletal system - echinococcosis;
• in skeletal muscles - trichinosis, cysticercosis of muscle tissue.

The lifespan of helminths in the body of the final host can be different, depends on the type of parasite and varies from a few weeks (toothworms) to a few years (tapeworm) and decades (fasciola).

Classification of the disease

There are two types of worms that parasitize humans:

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

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

• biohelminthiases;
• geohelminthiases;
• contact helminth infections.

Symptoms of helminthiasis

Helminths have different effects on the human body:

• antigenic effects, when local and general allergic reactions develop;
• toxic effect (waste products of helminths cause illness, weakness, dyspeptic symptoms);
• traumatic effect (when parasites are fixed on the intestinal wall, the blood supply is disrupted with subsequent necrosis and atrophy of the mucosa; absorption processes may be disrupted; mechanical compression of tissues 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 appears;
• neuro-reflex effect - irritation of nerve endings by helminths provokes bronchospasm, intestinal dysfunction, etc.;
• psychogenic effect, manifested by neurotic state, sleep disturbances;
• immunosuppressive effect.

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

In the initial acute phase, helminths often do not yet lay eggs, sensitization of the body 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 appear with pronounced clinical manifestations.The acute phase lasts from 1 to 4 months, sometimes 8-10 months or more.

Complaints from patients in the acute phase:

• temperature increase from several days to two months (low fever or above 38ºС, accompanied by chills, 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, simulating symptoms of pneumonia, asthmatic syndrome, hemoptysis;
• abdominal pain, nausea, vomiting, stool disorders.

At the end of this phase of helminth infections, acute allergic phenomena gradually decrease, 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 parasites in 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 (needleworm, trichuriasis, etc.), mechanical effects (an echinococcal cyst in the liver grows, compresses neighboring organs; cysticerci - in the brain), a secondary inflammatory disorder (inflammatory ishy-induoden).avitaminosis), functional disorders of the stomach and duodenum, secondary immunodeficiency, etc.

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

ABOUTintestinal helminthiasesThe following syndromes are characteristic:

• dyspeptic (stomach discomfort, feeling full after eating, early satiety, bloating, vomiting);
• painful;
• asthenoneurotic (feeling of extreme fatigue, increased excitability and nervous irritability).

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

Intestinal cestodes(taeniarrhizosis, diphyllobothriasis, hymenolepiasis, taeniasis and others) 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.

Breast worm diseasemanifests with 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 serious consequences.

For diseases caused by parasitism of migratory larvaezoohelminthswhen a 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), roundworms of dogs and cats, fortylids (nematodes).When a person comes into contact with soil or water, helminth larvae penetrate the skin.There is a feeling of burning, tingling or itching at the site of the introduction of the helminth.There may be a short-term fever and signs of general illness.After 1-2 weeks (less often 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, there may be disease, allergic exanthema (redness of the skin).In the human intestine, 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 disrupt the function of the organs.When tapeworm larvae (cysticerci, tsenura) are located in the membranes and substance of the brain, headaches, signs of cerebral hypertension, paresis and paralysis and epileptiform convulsions are observed.The larvae can also be located in the spinal cord, in the eye cavity, in the serous membranes, in the 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 body of the host.

Diagnosis of helminthiasis

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

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

• Clinical blood test: general analysis, leukoformula, ESR (with microscopy of a blood spot in the presence of pathological changes);
• Biochemical blood test:
• total protein, 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;
• 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, saliva, muscle tissue, rectal and perianal mucus.

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

• Analysis of feces for helminth eggs.
• Test for enterobiasis (worm eggs), swab.
• Microscopic examination of feces to detect eggs of the enterobiasis pathogen Enterobius vermicularis (leg worms).
• Test for enterobiasis (worm eggs), shoulder.
• The analysis is necessary if there is a suspicion of worm infection, as well as during hospitalization and registration of a medical file.
• Analysis for kindergarten and school.

The children's exam program is intended to be completed before they enter kindergarten or school.The results of these studies are necessary to obtain a medical certificate in accordance with form 026U approved by the Ministry of Health of the Russian Federation.

Conducting immunological studies - determination of specific antibodies to helminths:

• antibodies to roundworm IgG;
• anti-Echinococcus IgG;
• IgG antibodies to Toxocar antigens;
• Anti-Opisthorchis felineus IgG (IgG-class antibodies to cat bite antigens);
• 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.

A test aimed at detecting IgG antibodies to the causative agent of strongyloidiasis is used for the 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:

• simple 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 scan of the chest and mediastinum;
• CT scan of the brain and skull.

Which doctors should I contact?

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

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

Treatment of helminthiasis

Most people with helminth infections do not require hospitalization.Patients with tissue helminthiasis, 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 administration and dosage of the drug depends on the age and body weight of the patient and is determined by the doctor.

Desensitizing, detoxifying 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 medications are needed.

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

Complications

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

Prevention of helminthiasis

Preventive measures aimed at preventing helminth infection include:

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

With regular contact with pets, children in children's groups, contact with the ground, hobbies of fishing or hunting, frequent trips to exotic countries, prevention can be carried out through the use of medications.Drug prophylaxis should 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 the attending physician.To make a diagnosis and prescribe the appropriate treatment, you should contact your doctor.