Symptoms, diagnosis and treatment of the most common human helminthiases

In this article we will try to figure out what symptoms are most common in helminthiasis in adults, whether they can be asymptomatic, and also what types of helminthic 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.Depending on the class of pathogen, all human helminthiases are classically divided into:

1. Nematodes are helminthic 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 the parasitism of tapeworms or their larval forms.The most common cestodoses are diphyllobothriasis, taeniasis and teniarinchiasis, hymenolepiasis and echinococcosis.
3. Trematodes are helminthic infections caused by different types of flukes.The most common diseases in our country are opisthorchiasis, clonorchiasis, more rarely fascioliasis and very rarely paragonimiasis.

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

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

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

Which population groups are most likely to be infected?

Helminthic infestations 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 soil-transmitted helminthiasis 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 meat, fish, seafood, raw or poorly processed herbs, etc.Great importance is given 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 living in poor sanitation conditions, with a lack of access to water resources and quality sanitation facilities.
7. People closely linked to agriculture and livestock, living near animals.

When and who should be tested?

Depending on belonging to risk groups and the characteristics of the course of helminthic 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 working 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 ensure 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 an 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 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 suffering from low-grade fever of unknown etiology for quite 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 treatments.Anemia due to vitamin B12 deficiency accompanies 2 to 4% of cases of diphyllobothriasis, less often with teniarinchiasis, ascariasis and other helminthiases.

Features of the course of helminthic infestations

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

1. Infection and its clinical manifestations.The majority of helminth infections do not have any symptoms of infection, but with strongyloidiasis, hookworm and some others, cecarariasis occurs - diseases caused by the penetration of larvae into the skin.
2. The incubation period is the period from the moment of infection until 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 generally varies 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 people with “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 infestation depends on the lifespan of helminths and the likelihood of self-infection.

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

1. Diagram 1: the progression of the disease has the shape of a sinusoid.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 development is characteristic of opisthorchiasis, clonorchiasis, fascioliasis and strongyloidiasis.
2. Diagram 2: the evolution of helminthiases has the shape of a plateau.Infection with a subsequent increase in symptoms to a certain point, after which the patient finds that the symptoms remain constant or decrease and disappear.A similar course is typical for many invasions: trichinosis, taeniasis, diphyllobothriasis, ascariasis.
3. Diagram 3: the course of helminthiasis is characterized by a continuous increase in symptoms, which can ultimately lead to the death of the patient.Usually these are massive invasions or helminthiasis, occurring with dissemination against the background of immunodeficiency (disseminated strongyloidiasis).

Next, let's find out where worms live in the human body.Helminthic infections can affect any human organ, however, for systematization, several main “preferred” localizations in the host body can be identified:

1. The intestine is the most logical habitat for many human worms, e.g. roundworms, pinworms, whipworms, hookworms, bovine and pork tapeworms, etc.Here, the parasite attaches itself to the intestinal wall in one of the ways and carries out its "subversive" activity, most often stealing nutrients from the host's food.
2. The liver and bile ducts are the preferred habitat of opisthorchids, clonorchids and fasciolas.In addition, 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 (roundworm, hookworm, intestinal eel) cannot take place without the migration of larvae through the bronchopulmonary system.For other helminths, the lungs are the final target and habitat for adult individuals (paragonimiasis).
4. Central nervous system.It is most often 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. As a rule, the skin becomes the habitat of larval forms, as well as various filariae.
6. Eyes - filariasis, toxocariasis.
7. Venous plexus of the bladder, uterus and intestines in schistosomiasis.

Symptoms of helminthiasis

Generally speaking, the clinical picture of helminthic infestations 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 hives, 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 flatulence.Diarrhea or loose stools without an increase in bowel movement frequency are common.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 the pain is more precise.Sometimes pain syndrome due to helminthic infestations can mimic an "acute abdomen."
5. Bronchopulmonary.Most often caused by the migration of parasite larvae into the alveoli, followed by movement towards the bronchial tree, trachea and oropharynx.The main symptoms of 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 harsh or harsh breathing 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.Clinical manifestations in this case are different.Chronic cough with sputum and blood, hemoptysis, radiological changes such as pneumofibrosis, cystic lesions of the 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 flight (ascariasis, taeniasis, diphyllobothriasis, etc.), dysfunction of the stomach and intestines (teniarinosis, taeniasis, etc.) and exposure to toxins.Anemia is most commonly a microcytic iron deficiency, and in some helminthiases it is macrocytic and B-12 deficient.
7. Asthenia, 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.It is difficult for the patient to concentrate on work and concentrate.An infected person may experience unexplained weight loss, loss of appetite (or, conversely, increased appetite).
8. Intoxication-inflammatory syndrome manifests itself in the form of an increase in temperature up to 38 degrees and above, myalgia and arthralgia, leukocytosis and an increase in ESR in the BCC.The degree of severity depends on the patient's immune status and the phase of invasion.The acute phase occurs more often than the chronic phase with fever and flu-like illness.The chronic phase is more characterized 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 table below we have tried to summarize the available information on the symptoms of worm infection that accompany the most common helminthic infestations in humans.

Helminthiasis	Infection symptoms	Incubation period	Acute phase	Chronic phase
Enterobiosis	No	10-15 days	Perianal itching, diffuse abdominal pain, rarely diarrhea, nausea, vomiting.Dyssomnia, nighttime screams and crying in children.Persistent vulvovaginitis, synechiae of the lips. The total duration of the invasion is about a month or two (if there is no reinfection)
Ascariasis	No	About a week	Up to 2 weeks, the acute phase is caused by the migration of larvae.Symptoms during this period are fever, muscle and joint pain, 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), rumbling 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 stools, the presence of blood and mucus in the stool (the total duration of the invasion can be up to 5-7 years).
Diphyllobothriasis	No	Cleared, as the clinical picture of the invasion gradually develops	There is no acute phase as such.Symptoms appear and progress slowly.General asthenia, worsening 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 (paresthesias, changes in sensitivity and motor skills, etc.). The duration of the invasion can be up to 10 years or more.
Taeniasis and teniarinhoz	No	Cleared, as the clinical picture of the invasion gradually develops	There is no acute phase as such.The following symptoms appear and become more pronounced: 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, skin rashes such as hives, rarely lesions of the nervous system such as Ménière's syndrome, epileptiform seizures.
Opisthorchiasis	No	2-4 weeks	Increased temperature, weakness, fatigue, eosinophilia and leukocytosis, pain in the abdomen and liver, loose stools, allergic skin rash, hepatosplenomegaly, jaundice.	Symptoms of intestinal and hepatobiliary dyspepsia, hepatomegaly, jaundice, liver pain, there may be biliary colic, pain in the girdles (pancreatitis), a gradual increase in liver failure.
Clonorchiasis	No	2-3 weeks	Same as opisthorchiasis, but more pronounced	The same as for opisthorchiasis.High probability of developing cirrhosis and cholangiocarcinoma
Hookworm and necatorosis	2-3 days after infection, a papular or urticarial rash appears at the site of larvae penetration, often resembling tortuous passages.The duration of this period can be from 1.5 to 2 weeks.	Almost absent	Due to larvae migration, approximately 2-4 weeks.Fever, rash, 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 significant criterion is hypoalbuminemia, edema syndrome.Nausea, vomiting, pain in the epigastric region, flatulence, fatigue, headache, general asthenia.The total duration of the invasion can be up to 20 years.
Hymenolepiasis	No	This is expressed implicitly, for the maturation of an adult from a larva, 2-3 weeks are enough	Thus, 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 skin rash, urticaria, angioedema, allergic rhinitis.Pale skin with an icteric tint.Body temperature is often normal.
Fascioliasis	No	1-8 weeks	Fever, liver and epigastric pain, jaundice, hepatomegaly, loose stools, allergic skin rash, eosinophilia and leukocytosis	Hepatomegaly, liver pain, hepatobiliary dyspepsia, increasing liver failure, secondary cholecystitis and pancreatitis
Strongyloidiasis	On days 1 and 2, slight itching and a papular rash appear at the site of larvae penetration, which quickly disappear.	Almost absent	On the 3-4th day from the moment of infection, fever, myalgia, joint pain, cough with sputum, wet and dry wheezing appear, and bronchial obstruction is possible.X-ray reveals volatile eosinophilic infiltrates (Leffler syndrome).An allergic rash often appears on the skin.	Pain in the epigastric and periumbilical areas, less often in the liver, belching, heartburn, nausea, vomiting, loss of appetite and weight, biliary dyspepsia, diarrhea (usually enteritis type, impurities in the stool are rare, usually with massive invasion), hepatomegaly, jaundice.The infestation 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, 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, rash depending on the type exanthema, in severe cases hemorrhagic, high fever (sometimes mild 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, sharp 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 mild, prolonged fever, prolonged cough with sputum and blood, hemoptysis, chest pain, shortness of breath, weight loss, X-ray showing 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 during a visit to the doctor.How do you know if there are worms in the human body?Is it possible to do it yourself without leaving home?

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

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

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

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

For different invasions, the range of laboratory tests is different.It is important to understand that standard analysis of stool for helminth eggs and scraping for enterobiosis are screening methods aimed at identifying the most common intestinal helminth infections in risk groups.At the same time, single microscopy is only about 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.

Drug treatment and chemoprophylaxis

Treatment of human helminthiasis involves the prescription of appropriate anthelmintic agents, as well as symptomatic and pathogenetic agents.In this article we will not consider in detail doses and treatment regimens for individual helminthic infestations;it will only be noted that the prescription of medications must be carried out by a doctor (pediatrician, therapist, infectious disease specialist, parasitologist) based on the clinical picture, laboratory analysis data and the patient's condition.

Chemoprophylaxis of helminthiasis is the prophylactic administration of anthelmintic drugs active against geohelminthic infections in risk groups and endemic areas.As the overall incidence of soil-transmitted helminthiasis is low in the general population, chemoprophylaxis can be performed once a year, preferably in the fall or spring. 

Preventive measures

Measures aimed at preventing infection with worms are conventionally divided into individual and public.Individual prevention includes:

1. Compliance with the rules of personal hygiene between family members and in groups, teaching children the rules and monitoring their implementation.
2. Careful processing of greens, vegetables and fruits before direct consumption.
3. Refusal to consume raw and undercooked meat of pork, 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, in particular salted, smoked, dried, caviar and other fish products.
5. Drink only good quality water for drinking and cooking, including when traveling.
6. Before leaving for tropical and subtropical countries, it is necessary to obtain the opinion of an infectious disease specialist (parasitologist) and laboratory diagnostic recommendations after return.The infectious disease specialist also decides on the need for chemoprophylaxis.
7. Refusal to swim in fresh water, walk barefoot or lie on grass in endemic tropical countries.
8. Refusal to eat on the street, in cafes and other unverified public catering establishments.
9. Annual clinical examination with OAC, OAM, standard coproovoscopy and scraping for enterobiasis.These events are especially relevant for families with children, adults working in organized children's groups, hospitals, sanatoriums, etc.

Public prevention involves organizing control of food products offered for sale in stores and markets, timely identification of sick pets and infected people, as well as their treatment.Monitoring water resources, improving populated areas, assessing the degree of infection of wild mammals, controlling the limits of natural focal helminthiasis and the number of stray animals are of great importance.