Symptoms, diagnosis and treatment of the most common human helminthiasis.

In this article we will try to find out what symptoms are most common in helminth infections in adults, whether they can be asymptomatic and also what types of helminth infestations are most common in our country.

Introduction to terminology

Human helminth infections are usually caused by parasitic worms of three classes: Nematoda (nematodes) - roundworms, Cestoda (cestodes) - tapeworms, Trematoda (trematodes) - flukes.According to the class of pathogen, all human helminthiases are conventionally divided into:

1. Nematodes are helminth infections associated with infestation by roundworms or their larvae.The best known nematodes are enterobiasis, ascariasis, hookworm, toxocariasis and strongyloidiasis.
2. Cestodoses are caused by parasitism of tapeworms or their larval forms.The most common cestodiases are diphyllobothriasis, taeniasis and taeniarynchiasis, hymenolepiasis and echinococcosis.
3. Flukes are helminth infections caused by different types of flukes.The most common diseases in our country are opisthorchiasis, clonorchiasis, less frequently fascioliasis and, very rarely, paragonimiasis.

In relation to the territory of our country, all helminthiases can be divided into:

1. Typical, that is, frequent among the population of our country;
2. Exotic, caused by the migration of the population and tourism to other countries.

Detection and treatment of exotic helminth infections is a more complex and time-consuming process, as laboratories may not have the necessary reagents to perform laboratory tests.The following types of helminthic infestations are typical for the territory of our country.

What population groups are most susceptible to infection?

Helminthic infestations occur most frequently in the following groups:

1. Young children due to active knowledge of the world and lack of personal hygiene skills.
2. Children organized in groups (kindergartens, schools, camps, sanatoriums, etc.).Close interaction, shared habitat, and toy exchange contribute to the spread of STH with a simple life cycle.
3. Adults who have close contact and work with children, including teachers and parents.
4. People with certain eating habits: consumption of meat, fish, shellfish, herbs, raw or poorly processed, etc.Great importance is attached to national cuisine (sushi, stroganina, yukola, porsa and other dishes), love for drying, salting and smoking.
5. People living in endemic, tropical and subtropical areas.
6. People who live in poor sanitation conditions, with lack of access to water resources and quality sanitation.
7. People closely related to agriculture and livestock, who live close to animals.

When and who should get tested?

Depending on the membership of risk groups and the characteristics of the course of helminth infestations, an examination for helminthiasis should be carried out in the following cases:

1. Children, organized and unorganized, at least once a year in the absence of any symptoms.
2. Adults who work with children and in catering establishments, doctors, sellers of children's items and food products.
3. Children and adults entering educational institutions, sanatoriums, hospitals, boarding houses, hospices and other institutions that provide for the presence of a large number of people in one area.
4. Children and adults with allergic skin and bronchopulmonary diseases resistant to traditional therapeutic methods and the elimination diet.
5. Children and adults with symptoms of chronic damage to the gastrointestinal tract: nausea, vomiting, diffuse abdominal pain, diarrhea, pain in the epigastric and periumbilical area, malabsorption syndrome.
6. Children and adults with symptoms of damage to the hepatobiliary system: hepatosplenomegaly, jaundice, pain in the right upper quadrant, increased AST, ALT, GGTP, alkaline phosphatase, portal hypertension.
7. Children and adults with low-grade fever of unknown etiology for a long time.
8. Children and adults with severe asthenic syndrome: frequent headaches, weight loss, bulimia or lack of appetite, unmotivated weakness, fatigue, sleep disturbances.
9. Children and adults with microcytic and normocytic anemia resistant to traditional treatment.B12 deficiency anemia accompanies 2-4% of cases of diphyllobothriasis, less frequently teniarynchiasis, ascariasis and other helminthiases.

Features of the course of helminthic infestations.

The course of any helminthic infestation can be divided into several periods:

1. The infection and its clinical manifestations.Most helminth infections do not present symptoms of infection, but in the case of strongyloidiasis, hookworms and some others, so-called cercariae appear, diseases caused by the penetration of larvae into the skin.
2. The incubation period is the time from the moment of infection to the first clinical manifestations.
3. The acute phase, most often caused by the migration of larvae into the human body, their molting, their maturation into sexually mature individuals, the first laying of eggs, and the first encounter of the human body with unknown antigens.The duration of the acute phase usually ranges from several days to several weeks.Sometimes the acute phase is absent or weakly expressed, which is more often observed with a low degree of invasion or in indigenous peoples who have "immune memory."
4. The chronic phase occurs in the absence of treatment or its ineffectiveness and is associated with the direct influence of sexually mature individuals.

The duration of the infestation depends on the life span of the helminths and the likelihood of autoinfection.

From this point of view, the course of all helminthiases can be represented in the form of several basic schemes.

1. Scheme 1: The course of the disease is sinusoid-shaped.Onset (time of infection): increase in symptoms to a certain level (degree of severity): transition to the chronic phase with periodic exacerbations.This type of course is characteristic of opisthorchiasis, clonorchiasis, fascioliasis and strongyloidiasis.
2. Scheme 2: The course of helminthiasis is plateau-shaped.Infection with subsequent increase in symptoms to a certain point, after which the patient notices that the symptoms remain constant or decrease and disappear.A similar course is typical for many invasions: trichinosis, taeniasis, diphyllobothriasis, ascariasis.
3. Scheme 3: The course of helminthiasis is characterized by a continuous increase in symptoms, which can ultimately lead to the death of the patient.These are, as a rule, massive invasions or helminthiases that occur with dissemination in the context of immunodeficiency (disseminated strongyloidiasis).

Next, let's see where worms live in the human body.Helminth infections can affect any human organ;However, for systematization, several main "favorite" locations on the host's body can be identified:

1. The intestine is the most logical habitat for many human worms, for example, roundworms, pinworms, whipworms, hookworms, bovine and porcine tapeworms, etc.Here the parasite adheres in one way to the intestinal wall and carries out its "subversive" activity, most often stealing nutrients from the host's food.
2. The liver and bile ducts are the favorite habitat of opisthorchids, clonorchids and fasciolae.In addition, the liver is often affected during the migration of helminth larvae, for example, lung flukes, echinococci, etc.
3. Lungs and bronchi.The life cycle of many nematodes (roundworms, hookworms, intestinal eels) cannot continue without the migration of larvae through the bronchopulmonary system.For other helminths, the lungs are the final target and habitat of adult individuals (paragonimiasis).
4. central nervous system.Most often it is affected by cysticercosis, echinococcosis, toxocariasis, paragonimiasis and other invasions.This is usually due to the migration of larval forms and their spread through the bloodstream.
5. The skin, as a rule, becomes the habitat of larval forms, as well as various filariae.
6. Eyes: filariasis, toxocariasis.
7. Venous plexuses of the bladder, uterus and intestines in schistosomiasis.

Symptoms of helminthiasis.

In general terms, the clinical picture of helminth infestations is made up of the following syndromes:

1. Toxic-allergic.The main reasons for the development of allergic and toxic reactions are the metabolic products of adult individuals and larval forms and the release of toxins by them.Worms in humans can cause skin rashes such as hives, allergic and atopic dermatitis, and sometimes eczema.The rashes have a recurring course and are difficult to respond to traditional treatment.
2. Dyspeptic.Dyspeptic symptoms include nausea, vomiting, heartburn, belching, bitterness in the mouth, and flatulence.Diarrhea or loose stools are common without increasing the frequency of bowel movements.Dyspepsia is more typical for helminths living in the intestines (ascariasis, trichuriasis, etc.) and rarely occurs with tissue helminthiases (echinococcosis, cysticercosis, toxocariasis, etc.).
3. Maldigestion and malabsorption syndrome.It is also more typical of intestinal invasions, especially those in which sexually mature parasites live in the small intestine and duodenum (taeniasis, diphyllobothriasis, etc.)
4. Abdominal pain: in children, more often diffuse, in the umbilical region, right iliac region, simulating appendicitis.In adults, the location of pain is more specific.Sometimes pain syndrome due to helminthic infestations can mimic an "acute abdomen."
5. Bronchopulmonary.Most often it is due to the migration of parasite larvae into the alveoli, followed by movement into the bronchial tree, trachea and oropharynx.The main symptoms in this phase are cough, usually productive, with mucous or mucopurulent sputum, the appearance of wet and dry wheezing, a change in the nature of breathing to hard or harsh with prolongation of exhalation.With such invasions (ascariasis, strongyloidiasis, hookworm), Loeffler syndrome can be observed.In some invasions (e.g. paragonimiasis), the lungs are the usual habitat of adult individuals.The clinical manifestations in this case are different.Chronic cough with sputum and blood, hemoptysis, radiological changes such as pneumofibrosis, and cystic lesions of lung tissue often mimic the picture of pulmonary tuberculosis.
6. Worms in humans can cause anemic syndrome.The development of anemia can be caused by direct consumption of the host's blood (hookworm), host theft (ascariasis, taeniasis, diphyllobothriasis, etc.), dysfunction of the stomach and intestines (taeniarinosis, taeniasis, etc.), and exposure to toxins.Anemia is most often a microcytic iron deficiency and, in some helminthiases, is macrocytic and vitamin B-12 deficient.
7. Asthenia, as a sign of the presence of worms in the human body, is characterized by sleep disturbances, dyssomnia, increased irritability, aggressiveness, increased fatigue, hyperactivity and attention deficit in children.The patient finds it difficult to concentrate at work and concentrate.An infected person may experience unexplained weight loss, loss of appetite (or, conversely, increased appetite).
8. Inflammatory intoxication syndrome manifests itself as an increase in temperature to 38 degrees or more, myalgias and arthralgias, leukocytosis and an increase in ESR in the blood count.The degree of severity depends on the patient's immune status and the invasion phase.The acute phase occurs more frequently than the chronic phase with fever and a flu-like condition.The chronic phase is characterized more by low-grade fever or normal body temperature.
9. Worms in humans are often the cause of unexplained asymptomatic eosinophilia.Eosinophilia is more characteristic of nematodes and trematodes and may be accompanied by general leukocytosis.

In the following table we have attempted to summarize the available information on the symptoms of worm infection that accompany the most common helminthic infestations in humans.

Helminthiasis	Symptoms of infection	Incubation period	Acute phase	chronic phase
enterobiasis	No	10-15 days	Perianal pruritus, diffuse abdominal pain, rarely diarrhea, nausea, vomiting.Dysomnia, nocturnal screams and crying in children.Persistent vulvovaginitis, synechiae of the lips. The total duration of the invasion is approximately one or two months (if there is no reinfection)
ascariasis	No	about a week	Up to 2 weeks, the acute phase is caused by the migration of the larvae.Symptoms during this period are fever, muscle and joint pain, skin rash and itching, signs of bronchitis or pneumonia (eosinophilic infiltrative changes in the lung tissue).Bronchoobstruction may occur.	Decreased appetite, nausea, vomiting, abdominal pain (near the navel, right iliac region), sounds in the intestines and bloating.Symptoms of asthenia are persistent headaches, weakness and fatigue.Symptoms of anemia and hypovitaminosis.Total duration of invasion (in the absence of reinfection) - 1 year
Trichocephalosis	No	1-1.5 months	Pain along the large intestine, right iliac region, nausea, vomiting, salivation, flatulence, instability of stool, presence of blood and mucus in stool (the total duration of invasion is up to 5-7 years).
Diphyllobothriasis	No	Erased, as the clinical picture of the invasion gradually develops.	There is no acute phase as such.Symptoms occur and progress slowly.General asthenia, increasing over time, skin rashes, diffuse abdominal pain, sometimes in the right iliac region, nausea, vomiting, loss of appetite and progressive weight loss, stool instability, signs of anemia, glossitis, hepatosplenomegaly, neurological symptoms (paresthesia, impaired sensitivity and motor function, etc.). The duration of the invasion is up to 10 years or more.
Taeniasis and taeniarinhoz	No	Erased, as the clinical picture of the invasion gradually develops.	There is no acute phase as such.The following symptoms appear and increase: weakness, fatigue, headaches and other symptoms of asthenia, mild or moderate anemia, diffuse abdominal pain and discomfort, bulimia or loss of appetite, progressive weight loss, drooling, nausea, vomiting, skin rashes such as hives, rarely damage to the nervous system such as Meniere's syndrome, epileptiform seizures.
opisthorchiasis	No	2-4 weeks	Increased temperature, weakness, fatigue, eosinophilia and leukocytosis, pain in the abdomen and liver area, loose stools, allergic rash, hepatosplenomegaly, jaundice.	Symptoms of intestinal and hepatobiliary dyspepsia, hepatomegaly, jaundice, pain in the liver, there may be biliary colic, pain in the waist (pancreatitis), gradual increase in liver failure.
clonorchiasis	No	2-3 weeks	The same as with opisthorchiasis, but more pronounced.	The same as for opisthorchiasis.High probability of developing cirrhosis and cholangiocarcinoma.
Hookworm and necatoriasis	2-3 days after infection, an itchy papular rash or urticaria appears at the site of penetration of the larvae, often resembling tortuous passages.The duration of this period is up to 1.5 to 2 weeks.	Virtually absent	Due to the migration of the larvae, about 2-4 weeks.Fever, skin rashes, symptoms of bronchitis, bronchopneumonia: productive cough, wet and dry wheezing, sometimes bronchial obstruction.The formation of volatile eosinophilic infiltrates in the lung tissue (Leffler syndrome) is characteristic.	The most important clinical sign is moderate to severe iron deficiency anemia.The second important criterion is hypoalbuminemia, edema syndrome.Nausea, vomiting, pain in the epigastric region, flatulence, fatigue, headache, general asthenia.The total duration of the invasion is up to 20 years.
hymenolepiasis	No	It is expressed implicitly, for the maturation of an adult from a larva, 2-3 weeks are enough.	As such, the acute phase is not pronounced;Symptoms increase and are characterized by nausea, vomiting, salivation, diffuse abdominal pain, and loose stools.Damage to the nervous system in the form of headaches, dizziness, fainting.Allergic manifestations: exanthema-like rash, urticaria, Quincke's edema, allergic rhinitis.Pale skin with jaundiced tint.Body temperature is usually normal.
fascioliasis	No	1-8 weeks	Fever, pain in the liver and epigastrium, jaundice, hepatomegaly, loose stools, allergic rash, eosinophilia and leukocytosis.	Hepatomegaly, liver pain, hepatobiliary dyspepsia, increased liver failure, secondary cholecystitis and pancreatitis.
strongyloidiasis	On days 1-2, slight itching and a papular rash appear at the site of penetration of the larvae, which quickly disappear.	Virtually absent	On the 3-4th day from the moment of infection, fever, myalgia, joint pain, cough with sputum, wet and dry wheezing occur, and bronchial obstruction is possible.Radiography reveals volatile eosinophilic infiltrates (Leffler syndrome).An allergic rash often appears on the skin.	Pain in the epigastric, periumbilical areas, less often in the liver, belching, heartburn, nausea, vomiting, loss of appetite and weight, biliary dyspepsia, diarrhea (usually enteritis type, impurities in feces are rare, usually with massive invasion), hepatomegaly, jaundice.The infestation lasts for years due to periodic self-infection.
trichinosis	There may be abdominal pain, nausea, vomiting, diarrhea.	From 1-2 days to 4-5 weeks, on average 10-25 days	After infection, the intestinal phase begins first: abdominal pain, nausea, diarrhea, then generalized: severe muscle pain, swelling of the eyelids, face, less often the torso, skin rash depending on the type. rash, in severe cases hemorrhagic, high fever (sometimes low-grade fever) for several weeks.	Encapsulation of larvae and their preservation in skeletal muscles for 10 years or more.
paragonimiasis	No	2-3 weeks, can be reduced to several days.	Abdominal pain, acute abdominal pain, diarrhea.Gastroenterological symptoms are replaced by symptoms of damage to the bronchi and lung tissue: cough with sputum, chest pain, pneumonia, exudative pleurisy.	Prolonged fever or low-grade fever, prolonged cough with sputum and blood, hemoptysis, chest pain, shortness of breath, weight loss, x-ray shows pulmonary fibrosis, pleural adhesions, thin-walled cysts in the lower parts of the lungs.

How to confirm the presence of worms in the body?

We have come to the most frequently asked questions when visiting a doctor.How to know if there are worms in the human body?Is it possible to do it yourself without leaving home?

Therefore, determining the presence of helminthic infestation at home is possible only in the following cases:

1. Visualization of worms in the feces (live or dead adult helminths, their fragments).Naturally, only those helminths that live in the human intestines can be found in feces.As a rule, helminths are detected during a massive infestation.
2. Visualization of tapeworm segments in stool.

In all other cases, the diagnosis can be confirmed by 2 main laboratory diagnostic methods:

1. Various modifications of ovoscopy.Worm eggs have morphological differences and microscopic sizes;Trying to examine them in the stool is useless.
2. Serological reactions, including PCR.

For different invasions, the spectrum of laboratory tests is different.It is important to understand that standard stool analysis for helminth eggs and scraping for enterobiasis are screening methods aimed at identifying the most common intestinal helminth infections in risk groups.At the same time, single microscopy is only 50% informative.You can see what worm eggs look like under a microscope in the figure below.The vertical scale represents the size in µm.

Pharmacological treatment and chemoprophylaxis.

Treatment of human helminthiases involves the prescription of appropriate anthelmintics, as well as symptomatic and pathogenic agents.In this article, we will not consider in detail the dosages and treatment regimens for individual helminthic infestations;We will only point out that the prescription of medications must be carried out by a doctor (pediatrician, therapist, infectious disease specialist, parasitologist) in accordance with the clinical picture, laboratory test data and the patient's condition.

Helminthiasis chemoprophylaxis is the prophylactic administration of anthelmintic drugs active against soil-transmitted helminth infections in risk groups and endemic areas.Since the overall incidence of STH among the population as a whole is low, chemoprophylaxis can be performed once a year, preferably in autumn or spring. 

Preventive measures

Measures to prevent worm infection are conventionally divided into individual and public.Individual prevention includes:

1. Compliance with the rules of personal hygiene among family members and in groups, teaching children the rules and monitoring their compliance.
2. Thorough processing of vegetables and fruits before direct consumption.
3. Refusal to consume raw, poorly cooked pork, beef and other animals, salted, dried and smoked meats that have not passed sanitary and epidemiological control.
4. Refusal to consume fish that has not passed sanitary and epidemiological control, including salted, smoked, dried fish products, caviar and others.
5. Drink only high-quality water for drinking and cooking, even when traveling.
6. Before leaving for tropical and subtropical countries, it is necessary to consult an infectious disease specialist (parasitologist) and recommendations for laboratory diagnostics after returning.The infectious disease specialist also decides on the need for chemoprophylaxis.
7. Refusing to swim in fresh water, walk barefoot or lie on the grass in endemic tropical countries.
8. Refuse to eat food on the street, unverified cafes and other public catering establishments.
9. Annual clinical examination with OAC, OAM, standard coproovoscopy and scraping for enterobiasis.These events are especially relevant in families with children, adults working in organized children's groups, hospitals, sanatoriums, etc.

Public prevention consists of organizing control of food products sold in stores and markets, timely identification of sick pets and infected people and their treatment.Of great importance is the monitoring of water resources, the improvement of populated areas, the assessment of the degree of infection of wild mammals, the control of the limits of natural focal helminthiases and the number of stray animals.