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 helminthiases 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.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 most well-known nematodes are enterobiasis, ascariasis, hookworm disease, toxocariasis, and strongyloidiasis.
2. Cestodoses are caused by parasitism of tapeworms or their larval forms.The most common cestodiasis are diphyllobothriasis, taeniasis and teniarinchiasis, hymenolepiasis, and echinococcosis.
3. Trematodes are helminth infections caused by different types of flukes.The most common diseases in our country are opisthorchiasis, clonorchiasis, less commonly fascioliasis, and very rarely paragonimiasis.

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

1. Typical, that is, often found 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, since 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.

Which population groups are most susceptible to infection?

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 geohelminthiasis with a simple life cycle.
3. Adults who have close contact and work with children, including teachers and parents.
4. Persons 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. Persons living in endemic areas, tropics and subtropics.
6. Persons living in poor sanitation conditions, with lack of access to quality water resources and sanitation.
7. Persons closely associated with agriculture and cattle breeding, living close to animals.

When and who needs to get tested?

Based on belonging to risk groups and the characteristics of the course of helminthic infestations, examination for helminthiases must be performed 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 goods 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 skin and bronchopulmonary allergic diseases that are resistant to traditional therapy 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 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-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 disturbance.
9. Children and adults with microcytic and normocytic anemia resistant to traditional treatment.B12-deficiency anemia accompanies 2-4% of cases of diphyllobothriasis, less often teniarinchiasis, ascariasis and other helminthiasis.

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 have no symptoms of infection, but with strongyloidiasis, hookworm and some others, 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 in the human body, their molting, maturation to sexually mature individuals, the first laying of eggs and the first meeting of the human body with unfamiliar 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 people 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 lifespan of the 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. Scheme 1: the course of the disease has the form of a sinusoid.Onset (moment of infection) – an 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 has the form of a plateau.Infection with a subsequent increase in symptoms up to a certain point, after which the patient notes 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 ultimately can lead to the death of the patient.These are, as a rule, massive invasions or helminthiasis, occurring with dissemination against the background of immunodeficiency (disseminated strongyloidiasis).

Next, let's look at 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 intestine is the most logical habitat for many human worms, for example, 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 favorite habitat of opisthorchids, clonorchids, and fasciolas.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, hookworm, intestinal eel) cannot proceed 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.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. 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

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 by them.Worms in humans can cause skin rashes such as urticaria, allergic and atopic dermatitis, and sometimes eczema.The 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 increasing the frequency of bowel movements are common.Dyspepsia is more typical for helminths living in the intestines (ascariasis, trichuriasis, etc.), and rarely occurs with tissue helminthiasis (echinococcosis, cysticercosis, toxocariasis, etc.).
3. Maldigestion and malabsorption syndrome.It is also more typical for 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 localization of pain is more specific.Sometimes the pain syndrome due to helminthic infestations can imitate an “acute abdomen”.
5. Bronchopulmonary.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 in this phase are a 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 disease), Loeffler's syndrome can be observed.In some invasions (for example, 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, cystic lesions of the lung tissue often imitate 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), stealing from the host (ascariasis, taeniasis, diphyllobothriasis, etc.), dysfunction of the stomach and intestines (taeniarinosis, taeniasis, etc.), and exposure to toxins.Anemia is more often microcytic iron deficiency, and in some helminthiasis 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 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 to 38 degrees and above, myalgia and arthralgia, leukocytosis and an increase in ESR in the CBC.The degree of its severity depends on the patient’s immune status and the phase of invasion.The acute phase more often than the chronic phase occurs with fever and a flu-like condition.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 most 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 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 itching, diffuse abdominal pain, rarely diarrhea, nausea, vomiting.Dyssomnia, night screams and crying in children.Persistent vulvovaginitis, synechiae of the labia. 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 the migration of 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), rumbling in the intestines and bloating.Symptoms of asthenia are persistent 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 large intestine, right iliac region, nausea, vomiting, salivation, flatulence, stool instability, presence of blood and mucus in the stool (total duration of invasion is up to 5-7 years).
Diphyllobothriasis	No	Erased, as the clinical picture of the invasion develops gradually	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 teniarinhoz	No	Erased, as the clinical picture of the invasion develops gradually	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, rashes like urticaria, rarely damage to the nervous system like 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, girdle pain (pancreatitis), a gradual increase in liver failure.
Clonorchiasis	No	2-3 weeks	The same as with opisthorchiasis, but more pronounced	The same as for opisthorchiasis.High likelihood of developing cirrhosis and cholangiocarcinoma
Hookworm and necatoriasis	2-3 days after infection, a papular or urticarial itchy rash appears at the site of penetration of the larvae, often resembling tortuous passages.The duration of this period is up to 1.5 - 2 weeks.	Virtually absent	Due to the migration of larvae, about 2-4 weeks.Fever, skin rashes, symptoms of bronchitis, bronchopneumonia - productive cough, wet, dry wheezing, sometimes bronchial obstruction.The formation of volatile eosinophilic infiltrates in the lung tissue (Leffler's 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 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-type rash, 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, pain in the liver, hepatobiliary dyspepsia, increasing liver failure, secondary cholecystitis and pancreatitis
Strongyloidiasis	On days 1-2, a slight itching and papular rash appears 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, moist and dry wheezing occur, and bronchial obstruction is possible.The radiograph reveals volatile eosinophilic infiltrates (Leffler's 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 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, the intestinal phase begins first - abdominal pain, nausea, diarrhea, then generalized - severe muscle pain, swelling of the eyelids, face, less often of the torso, rash according to the type exanthema, 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	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've 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 (adult living or dead 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 massive infestation.
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 sizes; trying to examine them in feces is useless.
2. Serological reactions, including PCR.

For different invasions, the range 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 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 helminthiases involves prescribing appropriate anthelmintic, as well as symptomatic and pathogenetic agents.In this article, we will not consider in detail the doses and treatment regimens for individual helminthic infestations; we will only note that the prescription of drugs should 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.

Chemoprophylaxis of helminthiasis is the prophylactic administration of anthelmintic drugs active against geohelminthic infections in risk groups and endemic areas.Since the overall incidence of geohelminthiases among the population as a whole is low, chemoprophylaxis can be carried out once a year, preferably in the fall or spring. 

Preventive measures

Measures to prevent infection with worms 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 implementation.
2. Thorough 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 obtain advice from an infectious disease specialist (parasitologist) and recommendations for laboratory diagnostics 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 the grass in endemic tropical countries.
8. Refusal to eat food on the street, unverified cafes and other public catering establishments.
9. Annual clinical examination with performing 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 over food products going on sale 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, improvement of populated areas, assessment of the degree of infection of wild mammals, control over the boundaries of natural focal helminthiases, and the number of stray animals.