Symptoms, diagnosis and treatment of the most common human helminthiases

In this article we will try to understand which symptoms are more common in helminthiases in adults, if they can be asymptomatic and also which types of helminthic infections are more common in our country.

Introduction to Terminology

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

1. Nematodes are helminthic infections associated with infection by roundworms or their larvae.The most common nematodes are enterobiasis, ascariasis, needleworm disease, toxocariasis and stronguloidiasis.
2. Cestodes are caused by parasitism of tapeworms or their larval forms.The most common cestodiasis are diphyllobothriasis, taenia and teniarynchiasis, hymenolepiiasis and echinococcosis.
3. Trematodes are helminthic infections caused by various types of flukes.The most common diseases in our country are opisthorchiasis, clonorchiasis, less often fascioliasis and very rarely paragonimiasis.

Regarding the territory of our country, all helminthiasis can be divided into:

1. Typical, therefore, often found in the population of our country;
2. Exotic, caused by population migration and tourism in 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 infections are typical for the territory of our country.

Which population groups are most susceptible to infection?

Helminthic infections occur more often 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 exchange of toys contribute to the spread of geohelminthiasis with a simple life cycle.
3. Adults who have close contact and work with children, including teachers and parents.
4. People with certain dietary habits: consumption of raw or poorly processed meat, fish, seafood, herbs, 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 areas, tropics and subtropics.
6. People living in poor sanitary conditions, with lack of access to quality water sources and sanitation.
7. People closely related to agriculture and animal husbandry, who live near animals.

When and who should be tested?

Based on belonging to the risk groups and the characteristics of the course of helminthic infections, examination for helminthiasis should be carried out in the following cases:

1. Children, organized and disorganized, at least once a year in the absence of any symptoms.
2. Adults who work with children and in catering establishments, doctors, sellers of goods and food products for children.
3. Children and adults who enter educational institutions, sanatoriums, hospitals, dormitories, hostels and other institutions that foresee the presence of a large number of people in one area.
4. Children and adults with allergic skin and bronchopulmonary diseases that are resistant to traditional methods of therapy and 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 peri-umbilical areas, malabsorption syndrome.
6. Children and adults with symptoms of damage to the hepatobiliary system - hepatosplenomegaly, jaundice, pain in the right hypochondrium, increased AST, ALT, GGTP, alkaline phosphatase, portal hypertension.
7. Children and adults with low temperature 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 disturbance.
9. Children and adults with microcytic and normocytic anemia resistant to traditional treatment.B12 deficiency anemia accompanies 2-4% of cases of difilobothriasis, less often teniarynchiasis, ascariasis and other helminthiasis.

Characteristics of the course of helminthic infections

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

1. Infection and its clinical manifestations.Most helminth infections have no symptoms of infection, but with strongyloidiasis, needleworm and some others, the so-called cercarioses occur - 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, 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 varies from a few days to a few weeks.Sometimes the acute phase is absent or weakly expressed, which is more often observed with a low degree of invasion or in indigenous people who have "immune memory".
4. The chronic phase occurs in the absence of treatment or its ineffectiveness and is associated with the direct impact of sexually mature individuals.

The duration of infection depends on the lifespan of helminths and the possibility of self-infection.

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 has the form of a sinusoid.The beginning (moment of infection) - an increase in symptoms to a certain level (degree of severity) - the transition to the chronic phase with periodic exacerbations.This type of course is characteristic of opisthorchiasis, clonorchiasis, fascioliasis and stronguloidiasis.
2. Scheme 2: the course of helminthiasis has the shape of a plateau.Infection with a subsequent increase in symptoms up 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, difilobothriasis, 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 helminthiasis, occurring with spread against the background 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" localizations in the host's body can be identified:

1. The intestines are the most logical habitat for many human worms, for example, roundworms, hookworms, whipworms, breast worms, tapeworms of cattle and pigs, etc.Here the parasite attaches to the intestinal wall in one of the ways and performs its "subversive" activity.
2. The liver and bile ducts are the preferred habitat of opisthorchids, clonorchids and fasciolae.Also, the liver is often affected during the migration of helminth larvae, for example, pulmonary fluke, echinococcus, etc.
3. Lungs and bronchi.The life cycle of many nematodes (ascaris, roundworm, intestinal eel) cannot continue without larval migration through the bronchopulmonary system.For other helminths, the lungs are the final target and habitat of adults (paragonimiasis).
4. Central nervous system.It is most often affected by cysticercosis, echinococcosis, toxocariasis, paragonimiasis and other invasions.This is usually due to the larval forms migrating and spreading through the bloodstream.
5. The skin, as a rule, becomes the habitat of larval forms, as well as various filarials.
6. Eyes - filariasis, toxocariasis.
7. Bladder, uterine and intestinal venous plexuses in schistosomiasis.

Symptoms of helminthiasis

In general, the clinical picture of helminthic infections consists 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 from them.Worms in humans can cause skin rashes such as urticaria, allergic and atopic dermatitis, and sometimes eczema.Rashes have a recurrent course and are difficult to respond to traditional treatment.
2. Dyspeptic.Dyspeptic symptoms include nausea, vomiting, heartburn, belching, bitterness in the mouth and bloating.Diarrhea or loose stools without increased frequency of bowel movements are common.Dyspepsia is more typical for helminths living in the intestine (ascariasis, trichuriasis, etc.), and rarely occurs with tissue helminthiasis (echinococcosis, cysticercosis, toxocariasis, etc.).
3. Maltreatment 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 navel region, right iliac region, simulating appendix.In adults, the localization of pain is more specific.Sometimes the pain syndrome due to helminthic infections can imitate an "acute abdomen".
5. Bronchopulmonary.It is most often caused by the migration of parasite larvae into the alveoli, followed by movement into the bronchial tree, trachea and oropharynx.The main symptoms at this stage are a cough, usually productive, with mucous or mucopurulent sputum, the appearance of wet and dry breathing, the change in the nature of breathing to difficult or harsh with prolonged exhalation.With such invasions (ascariasis, strongyloidiasis, needleworm disease), Loeffler's syndrome can be observed.In some invasions (for example, paragonimiasis), the lungs are the usual habitat of adult individuals.Clinical manifestations in this case are different.Chronic cough with sputum and blood, hemoptysis, radiological changes such as pneumofibrosis, 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 blood of the host (worm), theft from the host (ascariasis, taeniasis, diphyllobothriasis, etc.), dysfunction of the stomach and intestines (taeniarinosis, taeniasis, etc.) and exposure to toxins.Anemia is most often microcytic iron deficiency, and in some helminthiases it is macrocytic and B-12 deficient.
7. Asthenia, as a sign of the presence of worms in the human body, is characterized by sleep disturbance, dyssomnia, increased irritability, aggressiveness, increased fatigue, hyperactivity and attention deficit in children.It is difficult for the patient to focus on work and concentrate.An infected person may experience unexplained weight loss, loss of appetite (or, conversely, increased appetite).
8. Intoxication-inflammatory syndrome is manifested in the form of an increase in temperature to 38 degrees and above, myalgia and arthralgia, leukocytosis and an increase in ESR in CBC.The degree of its severity depends on the immune status of the patient and the stage of invasion.The acute phase more often than the chronic phase occurs with fever and flu-like conditions.The chronic phase is characterized more by low 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 table below we have tried to summarize the available information about the symptoms of worm infection accompanying the most common helminthic infections in humans.

Helminthiasis	Symptoms of infection	Incubation period	Acute phase	Chronic phase
Enterobiasis	No.	10-15 days	Perianal itching, diffuse abdominal pain, rarely diarrhea, nausea, vomiting.Dyssomnia, night screams and crying in children.Persistent vulvovaginitis, labial synechiae. The total duration of the invasion is about a month or two (if there is no re-infection)
Ascariasis	No.	About a week	Up to 2 weeks, the acute phase is caused by larval migration.Symptoms during this period are fever, muscle and joint pain, skin rash and itching, signs of bronchitis or pneumonia (eosinophilic infiltrative changes in lung tissue).Bronchoobstruction may occur.	Decreased appetite, nausea, vomiting, abdominal pain (near the navel, right iliac region), rumbling in the intestines and bloating.Symptoms of asthenia are constant headaches, weakness, fatigue.Symptoms of anemia and hypovitaminosis.Total duration of invasion (in the absence of re-infection) - 1 year
Trichocephalosis	No.	1-1.5 months	Pain along the colon, right iliac region, nausea, vomiting, salivation, flatulence, stool instability, the presence of blood and mucus in the stool (the total duration of invasion is up to 5-7 years).
Diphyllobothriasis	No.	It is hidden, as the clinical picture of invasion develops gradually	There is no acute phase as such.Symptoms appear and progress slowly.General asthenia, increasing over time, skin rash, 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 motor function, sensitivity, etc.). The duration of the occupation is up to 10 years or more.
Taeniasis and teniarynchosis	No.	It is hidden, as the clinical picture of invasion develops gradually	There is no acute phase as such.The following symptoms appear and increase: weakness, fatigue, headache 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, urticaria-like rash, rarely more severe damage to the nervous system, epiuretic syndrome.
Opisthorchiasis	No.	2-4 weeks	Fever, weakness, fatigue, eosinophilia and leukocytosis, abdominal and liver pain, loose stools, allergic rash, hepatosplenomegaly, jaundice.	Symptoms of intestinal and hepatobiliary dyspepsia, hepatomegaly, jaundice, pain in the liver, there may be biliary colic, abdominal pain (pancreatitis), a gradual increase in liver failure.
Clonorchiasis	No.	2-3 weeks	Same as with opisthorchiasis, but more pronounced	The same as for opisthorchiasis.High probability of developing cirrhosis and cholangiocarcinoma
Breastworm and nekatoriasis	2-3 days after infection, a rash with papular or urticarial itching appears at the site of larval penetration, often resembling twisted passages.The duration of this period is up to 1.5 - 2 weeks.	It is practically absent	Due to larval migration, about 2-4 weeks.Fever, skin rash, symptoms of bronchitis, bronchopneumonia - productive cough, wet, dry breathing, sometimes bronchial obstruction.The formation of volatile eosinophilic infiltrates in lung tissue is characteristic (Leffler syndrome).	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, bloating, fatigue, headache, general asthenia.The total duration of occupation is up to 20 years.
Hymenolepiasis	No.	Implicitly expressed, 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 headache, dizziness, fainting.Allergic manifestations - rashes of the exanthema type, urticaria, Quincke's edema, allergic rhinitis.Pale skin with an icteric tint.Body temperature is often 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, progressive hepatic failure, secondary cholecystitis and pancreatitis
Strongyloidiasis	On days 1-2, a slight itching and papular rash appears at the site of larval penetration, which quickly disappear.	It is practically absent	On the 3rd-4th day from the moment of infection, fever, myalgia, joint pain, cough with sputum, wet and dry shortness of breath appear, and bronchial obstruction is possible.Radiography reveals volatile eosinophilic infiltrates (Leffler syndrome).An allergic skin rash often appears.	Pain in the epigastric, periumbilical areas, less often in the liver, shortness of breath, 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 infection lasts for years due to regular 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, first the intestinal phase begins - abdominal pain, nausea, diarrhea, then generalized - severe muscle pain, swelling of the eyelids, face, less often the torso, redness according to the type. rash, in severe hemorrhagic cases, high fever (sometimes low fever) for several weeks.	Encapsulation of larvae and their storage in skeletal muscle for 10 years or more.
Paragonimiasis	No.	2-3 weeks, can be reduced to a few 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.	Fever or prolonged 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 can you tell if there are worms in the human body?Is it possible to do this yourself without leaving home?

So, it is possible to determine the presence of helminthic infestation at home only in the following cases:

1. Visualization of worms in feces (live or dead adult helminths, their fragments).Of course, only those toxins that live in the human intestines can be found in feces.As a rule, helminths are detected during mass infection.
2. Visualization of tapeworm segments in feces.

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

1. Various modifications of ovoscopy.Worm eggs have morphological differences and microscopic size;trying to examine them in feces is futile.
2. Serological reactions, including PCR.

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

Drug treatment and chemoprophylaxis

Treatment of human helminthiases includes the prescription of appropriate anthelmintic agents, as well as symptomatic and pathogenetic.In this article, we will not go into detail about dosages and treatment regimens for individual helminth infections;we will only emphasize that the prescription of drugs must be made by a doctor (pediatrician, therapist, infectious disease specialist, parasitologist) in accordance with the clinical picture, laboratory analysis data and the patient's condition.

Helminthiasis chemoprophylaxis is the prophylactic administration of anthelmintic drugs active against geohelminthic infections in risk groups and endemic areas.Since the general incidence of geohelminthiasis in the population as a whole is low, chemoprophylaxis can be carried out once a year, preferably in autumn or spring. 

Preventive measures

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

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

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