Symptoms, diagnosis and treatment of the most common human helminthiasis

In this article we will try to discover what are the most common symptoms of helminthiasis in adults, whether they can be asymptomatic and also which types of helminthic infestations are most common in our country.

Introduction to Terminology

Human helminth infections are generally caused by parasitic worms of three classes: Nematoda (nematodes) - roundworms, Cestoda (cestodes) - tapeworms, Trematoda (trematodes) - flukes.According to the class of the pathogen, all human helminthiases are conventionally 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 cestodiases are diphyllobothriasis, taeniasis and teniarinchiasis, hymenolepiasis and echinococcosis.
3. Trematodes are helminthic infections caused by different types of worms.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 helminthiases 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.

Detecting and treating 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.

Which 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 into groups (nursery schools, 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 eating habits: consumption of raw or poorly processed meat, fish, seafood, 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 areas, tropics and subtropics.
6. People who live in poor sanitation conditions, with lack of access to quality water resources and sanitation.
7. People closely linked to agriculture and livestock, who live close to animals.

When and who needs to take the test?

Based on belonging to risk groups and the characteristics of the course of helminthic infestations, 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 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 the same place.
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 lesions of 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 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 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.Most helminth infections do not have symptoms of infection, but with strongyloidiasis, hookworm and some others, so-called cercariae 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 several days to several weeks.Sometimes the acute phase is absent or weakly expressed, which is most often observed with a low degree of invasion or in indigenous people who have “immunological 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 the helminths and the likelihood of self-infection.

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

1. Scheme 1: the course 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 course is characteristic of opisthorchiasis, clonorchiasis, fascioliasis and strongyloidiasis.
2. Scheme 2: the course of helminthiasis has the form of a plateau.Infection with subsequent increase in symptoms to a certain point, after which the patient observes 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 lead to the patient's death.These are, as a rule, massive invasions or helminthiasis, occurring 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 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 porcine 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 fasciolae.In addition, the liver is often affected during the migration of helminth larvae, for example, lungworms, echinococci, etc.
3. Lungs and bronchi.The life cycle of many nematodes (ascaris, hookworm, intestinal eel) cannot proceed without 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 a habitat for larval forms, as well as various filaria.
6. Eyes - filariasis, toxocariasis.
7. Venous plexuses of the bladder, uterus and intestines in schistosomiasis.

Helminthiasis symptoms

In general, 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 hives, 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 intestine (ascariasis, trichuriasis, etc.) and rarely occurs with tissue helminthiasis (echinococcosis, cysticercosis, toxocariasis, etc.).
3. Poor digestion 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 specific.Sometimes pain syndrome due to helminthic infestations can mimic an “acute abdomen.”
5. Bronchopulmonary.Most often caused by the migration of parasite larvae to the alveoli, followed by movement to the bronchial tree, trachea and oropharynx.The main symptoms at this stage are a cough, generally productive, with mucous or mucopurulent sputum, the appearance of wet and dry wheezing, a change in the nature of breathing to strong or rough with prolongation of exhalation.With these 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 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 (teniarinosis, taeniasis, etc.), and exposure to toxins.The anemia is most often microcytic iron deficiency, and in some helminthiasis it 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.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 or more, myalgia and arthralgia, leukocytosis and an increase in ESR in the complete blood count.The degree of severity depends on the patient's immune status and the phase of invasion.The acute phase occurs more frequently than the chronic phase with fever and a flu-like condition.The chronic phase is most characterized by a 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 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 itching, diffuse abdominal pain, rarely diarrhea, nausea, vomiting.Dysomnia, nocturnal screams and crying in children.Persistent vulvovaginitis, synechiae of the labia. The total duration of the invasion is about 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 larvae.Symptoms during this period are fever, muscle and joint pain, 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 abdominal distension.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 in the stool, presence of blood and mucus in the stool (the total duration of the invasion is 5 to 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.
Teniasis and teniarinhoz	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, excessive salivation, nausea, vomiting, skin rashes such as urticaria, 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 region, loose stools, allergic skin rash, hepatosplenomegaly, jaundice.	Symptoms of intestinal and hepatobiliary dyspepsia, hepatomegaly, jaundice, liver pain, there may be biliary colic, waist pain (pancreatitis), gradually increasing liver failure.
Clonorchiasis	No	2-3 weeks	Same as in opisthorchiasis, but more pronounced	Same as for opisthorchiasis.High probability of developing cirrhosis and cholangiocarcinoma
Hookworm and necatoriasis	2-3 days after infection, a papular or urticarial rash appears at the site of penetration of the larvae, often resembling tortuous passages.The duration of this period is 1.5 to 2 weeks.	Practically absent	Due to larvae migration, about 2 to 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 lung tissue (Leffler syndrome) is characteristic.	The most important clinical sign is moderate to severe iron deficiency anemia.The second significant criterion is hypoalbuminemia, edematous 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 implicitly expressed that 2-3 weeks are enough for the maturation of an adult from a larva	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 - rash-like rash, urticaria, Quincke's edema, allergic rhinitis.Pale skin with icteric tinge.Body temperature is usually normal.
Fascioliasis	No	1-8 weeks	Fever, pain in the liver and epigastrium, jaundice, hepatomegaly, loose stools, allergic skin rash, eosinophilia and leukocytosis	Hepatomegaly, liver pain, hepatobiliary dyspepsia, increased 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.	Practically absent	On the 3-4th day from the moment of infection, fever, myalgia, joint pain, cough with sputum, wet and dry wheezing occur, 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 frequently in the liver, belching, heartburn, nausea, vomiting, loss of appetite and weight, biliary dyspepsia, diarrhea (usually enteritis type, impurities in the 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 to 2 days to 4 to 5 weeks, on average 10 to 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 trunk, rash depending on the type rash, in severe cases hemorrhagic, high fever (sometimes low 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 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 come to the most frequently asked questions when visiting a doctor.How do you know if there are worms in the human body?Is it possible to do this alone, without leaving home?

Thus, 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).Naturally, only helminths that live in the human intestine can be found in feces.As a rule, helminths are detected during a 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 candling.Worm eggs present morphological differences and microscopic sizes;trying to examine them in feces is futile.
2. Serological reactions, including PCR.

For different invasions, the range of laboratory tests is different.It is important to understand that standard analysis of feces 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 picture below.The vertical scale represents the size in µm.

Drug treatment and chemoprophylaxis

Treatment of human helminthiasis involves the prescription of appropriate anthelmintics, 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 medication prescription must be carried out by a doctor (pediatrician, therapist, infectious disease specialist, parasitologist) according to the clinical picture, data from laboratory tests and the patient's condition.

Helminthiasis chemoprophylaxis is the prophylactic administration of anthelmintic drugs active against geohelmintic infections in risk groups and endemic areas.As 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 worm infection are conventionally divided into individual and public.Individual prevention includes:

1. Compliance with personal hygiene rules among family members and in groups, teaching children the rules and monitoring their implementation.
2. Complete processing of vegetables and fruits before direct consumption.
3. Refusal to consume raw and undercooked meat from pigs, cattle 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, 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 guidance from an infectious disease specialist (parasitologist) and recommendations for laboratory diagnosis upon 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, unverified cafes and other public catering establishments.
9. Annual clinical examination with ACO, 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 for 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, the improvement of populated areas, the assessment of the degree of infection of wild mammals, the control of the limits of natural focal helminthiasis and the number of stray animals.