Helminthiasis

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

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

Causes of helminthiasis

Currently, more than 70 of the known 250 helminths that parasitize the human body are found in our country.The most common are roundworms (roundworms, pinworms, trichinae worms, whipworms), tapeworms (porcine, bovine and dwarf tapeworms, broad tapeworm, echinococcus) and flukes (liver and cat flukes).

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

Infection with helminths most often occurs after their eggs and/or larvae enter the body.Depending on the infection mechanism 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 through contact.

Pork tapeworms, beef tapeworms, echinococci and other types of worms develop by successively changing from 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 full heat treatment:

• beef infected with beef tapeworm larvae;
• pork infected with Finnish pork tapeworm;
• lightly salted and raw fish with larvae of Opisthorchis or broad tapeworm;
• Raw water or vegetables and fruits treated with this water.

Whipworms, roundworms, hookworms and necators develop without intermediate hosts.The eggs and larval forms of these parasites enter the soil in the feces.If the rules of personal hygiene are not observed, they penetrate the body of a new host.

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

Helminths of a certain species parasitize in certain organs and cause various helminthiasis:

• in the large intestine - pork, bovine, dwarf tapeworms, nematodes (hookworms, roundworms, Strongyloides), pinworms, whipworms.From the intestinal lumen, pork tapeworm larvae can enter the bloodstream and spread throughout the body, settling in fatty tissue, muscle vessels, eye chambers and the brain.
• in the liver and biliary tract - trematodes (Opisthorchis, Clonorchis, Fasciola).Echinococcal cysts are located mainly in the liver, and after their rupture, daughter bladders can be found in the mesentery, peritoneal layers, spleen and other organs;
• in the respiratory organs - echinococci, alveococci, pulmonary flukes that cause paragonimiasis;
• in the nervous system - schistosomiasis, paragonimiasis, echinococcosis and alveococcosis;
• in the organs of vision - oncocercosis, loiasis, complicated forms of taeniasis;
• in the circulatory system - nekatoriasis, schistosomiasis, diphyllobothriasis;
• in the lymphatic system - filariasis, trichinosis;
• in the skin and subcutaneous tissue - hookworm, oncocerciasis, 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 definitive host can be variable, depends on the type of parasite and ranges from several weeks (pinworms) to several years (tapeworms) and decades (Fasciola).

Classification of the disease

There are two types of worms that parasitize humans:

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

Depending on the routes of spread of parasites and the features of their biology, they are distinguished:

• biohelminthiases;
• geohelminthiasis;
• Contact worm 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 malaise, weakness and dyspeptic symptoms);
• traumatic effect (when fixing parasites on the intestinal wall, the blood supply is disrupted with necrosis and subsequent atrophy of the mucous membrane; absorption processes may be disrupted; mechanical compression of tissues by helminths);
• secondary inflammation resulting from bacterial invasion after migrating helminth larvae;
• Violation of metabolic processes;
• Anemia occurs as a result of blood consumption by some helminths.
• Neuroreflex effect – irritation of nerve endings by helminths leads to bronchospasm, intestinal disorders, etc.;
• psychogenic effect, manifested in neurotic states and sleep disorders;
• immunosuppressive effect.

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

In the acute initial stage, helminths usually do not release eggs; the body becomes sensitized (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 stage lasts 1 to 4 months, sometimes 8 to 10 months or longer.

Complaints of patients in the acute stage:

• increased temperature from several days to two months (mild fever or above 38 ° C, accompanied by chills, severe weakness and sweating);
• itchy, recurring skin rashes;
• local or generalized edema;
• Enlargement of regional lymph nodes;
• pain in muscles and joints;
• Cough, asthma attacks, chest pain, persistent catarrhal symptoms, bronchitis, tracheitis, symptoms simulating pneumonia, asthmatic syndrome, hemoptysis;
• Abdominal pain, nausea, vomiting, stool disorders.

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

The acute stage becomes subacute as the “young” helminths gradually mature.Then comes the chronic stage, which corresponds to the development of parasites into sexually mature individuals.The clinical picture develops against the background of the toxic effect of helminth waste products, the traumatic effect of helminths on organs (hookworm, trichuriasis, etc.), mechanical influences (an echinococcal cyst grows in the liver, compresses neighboring organs; cysticerci - in the brain), a secondary inflammatory process (duodenitis is observed in strongyloidiasis), metabolic disorders (hypo- or avitaminosis), functional disorders of the stomachand duodenum, secondary immunodeficiencies, etc.

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

ForIntestinal helminthiasisThe following syndromes are characteristic:

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

Enterobiasis is characterized by nocturnal perianal itching.Massive roundworm infestations can lead to intestinal obstruction, pancreatitis and obstructive jaundice.

intestinal cestodoses(Taeniarinhoz, Diphyllobothriasis, Hymenolepiasis, Taeniasis and others) are asymptomatic or have a small number of symptoms (with symptoms of dyspepsia, pain, anemia).

Liver trematodes(Fascioliasis, Opisthorchiasis, Clonorchiasis) Cause:

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

Hookworm diseasemanifested by asthenovegetative syndrome (weakness, fatigue, pallor of the 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 very end of urination, frequent urge to urinate and 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.

In diseases caused by parasitism of migratory larvaeZoohelminthswhen a person is not the natural host, distinguish between cutaneous and visceral forms.The cutaneous form is caused by the penetration of certain animal helminths under the human skin: schistosomatids of waterfowl (trematodes), hookworms of dogs and cats, strongyles (nematodes).When a person comes into contact with earth or water, helminth larvae penetrate the skin.There is a feeling of burning, tingling or itching at the site of penetration of the helminth.Short-term fever and signs of general malaise may occur.Recovery occurs after 1-2 weeks (less often 5-6 weeks).

The visceral form arises from the ingestion of worm eggs with water and food.At the beginning of the disease, you may feel unwell and have an allergic rash (skin rash).In the human intestine, larvae hatch from worm eggs, penetrate through the intestinal wall into the blood, reach the internal organs, where they grow and reach a diameter of 5-10 cm, compressing tissues and disrupting the functioning 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, epileptiform convulsions are observed.Larvae can also be located in the spinal cord, eyeball, serous membranes, intermuscular connective tissue, etc.

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

Diagnosis of helminthiasis

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

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

• clinical blood test: general analysis, leukoformula, ESR (with microscopy of a blood smear for pathological changes);
• biochemical blood test:
• total protein, albumin, protein fractions; 
• Assessment of renal function indicators (urea, creatinine, glomerular filtration);
• Assessment of liver function indicators (bilirubin, ALT, AST, alkaline phosphatase);
• alpha amylase pancreas;
• Assessment of carbohydrate metabolism: glucose (in the 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 their development, it is recommended to donate feces three times - every 3-4 days.

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

The child examination program should be completed before entering kindergarten or school.The results of these studies are required 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 against roundworm IgG;
• anti-echinococcus IgG;
• IgG antibodies against Toxocar antigens;
• Anti-Opisthorchis felineus IgG (antibodies of the IgG class against cat fluke antigens);
• IgG antibodies against Trichinella antigens;
• Antibodies against the pathogen of anisakiasis (nematodes of the genus Anisakis), IgG;
• Antibodies against the pathogen of clonorchiasis, IgG;
• Antibodies against Strongyloides stercoralis, the causative agent of strongyloidiasis, IgG.

A test for the detection of IgG antibodies against 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 the chest organs;
• comprehensive ultrasound examination of the abdominal organs (liver, gallbladder, 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 family doctor and take your child to 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, as well as patients with severe and complicated disease are treated in the hospital.

Therapy is carried out with anthelmintics.The frequency of administration and dosage of the drug depends on the patient's age and body weight 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, with an allergic reaction and itching - antihistamines, with severe edema - diuretics.In severe cases, hormonal medications are required.

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

Complications

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

Prevention of helminthiasis

Preventive measures to prevent helminth infection include:

• Compliance with the rules of personal hygiene (use of a single towel, personal hygiene items and other accessories for daily use);
• Only use high-quality water in everyday life.
• regular vaccination and deworming of pets;
• Thoroughly washing vegetables, fruits and berries before consumption;
• sufficient heat treatment of meat and fish products.

With regular contact with pets, children in children's groups, contact with the earth, hobbies such as fishing or hunting, frequent trips to exotic countries, prevention can be achieved through the use of medication.Drug prophylaxis must be taken by the whole family twice a year (e.g. in spring and autumn).

IMPORTANT!

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