Symptoms, diagnosis and treatment of the most common helminth infections in humans

In this article, we will try to understand what symptoms are most common in helminthiasis in adults, whether they can be asymptomatic, as well as what types of helminth invasions 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 the pathogen, all human helminthiases are conditionally divided into:

1. Nematodes are helminth infections associated with infection with roundworms or their larvae.The most famous nematodes are enterobiosis, ascariasis, hookworm, toxocariasis and strongyloidiasis.
2. Cestodes are caused by the parasitism of tapeworms or their larval forms.The most common cestodiases are diphyllobothriosis, taenia and teniarynchiasis, hymenolepiasis and echinococcosis.
3. Trematodes are helminth infections caused by various types of flukes.The most common diseases in our country are opisthorchosis, clonorchosis, less often fascioliasis and very rarely paragonimosis.

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

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

The 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 helminth invasions 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 are organized into 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 eating habits: consumption of raw or poorly processed meat, fish, seafood, herbs, etc.Great importance is attached to the national cuisine (sushi, stroganina, yukola, pork and other dishes), the love for drying, salting and smoking.
5. Persons living in endemic areas, tropics and subtropics.
6. People living in poor sanitation, with no access to quality water resources and sanitation.
7. Persons closely related to agriculture and animal husbandry, living near animals.

When and who should be examined?

Based on belonging to the risk groups and the characteristics of the course of helminthic invasions, the 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 symptoms.
2. Adults working with children and in catering establishments, doctors, sellers of children's goods and groceries.
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 skin and bronchopulmonary allergic diseases, resistant to traditional methods of treatment 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 periumbilical regions, 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 disorders.
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 teniarynchiasis, ascariasis and other helminthiasis.

Characteristics of the course of helminthic invasions

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

1. Infection and its clinical manifestations.The majority of helminth infections have no symptoms of infection, but with strongyloidosis, hookworm and some others, the so-called cercarioses 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 the 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 more often observed with a low degree of invasion or in local 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 invasion depends on the life expectancy of the helminths and the probability of self-infection.

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

1. Scheme 1: the course of the disease has the form of a sinusoid.Beginning (moment of infection) - increase of symptoms to a certain level (degree of severity) - transition to a chronic phase with periodic exacerbations.This type of course is characteristic of opisthorchosis, clonorchosis, fascioliasis and strongyloidiasis.
2. Scheme 2: the course of helminthiasis has the form of a plateau.An infection with a subsequent increase in symptoms until 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: trichinellosis, teniosis, 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 helminthiasis, occurring with spread against the background of immunodeficiency (disseminated strongyloidosis).

Next, let's look at where worms live in the human body.Helminth infections can affect any human organ, but 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, pinworms, whipworms, hookworms, beef 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 fascioli.Also, the liver is often affected during the migration of helminth larvae, for example, lung fluke, echinococcus, etc.
3. Lungs and bronchi.The life cycle of many nematodes (ascaris, hookworm, intestinal eel) cannot continue without the migration of larvae through the bronchopulmonary system.For other helminths, the lungs are the final destination and habitat of adults (paragonimosis).
4. Central nervous system.It is most often affected by cysticercosis, echinococcosis, toxocarosis, paragonimosis 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, toxocarosis.
7. Venous plexuses of the bladder, uterus, and bowel 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.In humans, roundworms 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 flatulence.Diarrhea or loose stools without increasing bowel frequency are common.Dyspepsia is more characteristic of helminths living in the intestines (ascariasis, trichuriasis, etc.), and rarely occurs in tissue helminths (echinococcosis, cysticercosis, toxocarosis, etc.).
3. Indigestion and malabsorption syndrome.It is also more characteristic of intestinal invasions, especially those in which the sexually mature parasites live in the small intestine and duodenum (taeniasis, diphyllobothriasis, etc.)
4. Abdominal pain: in children - more often diffuse, in the navel area, right iliac area, simulating appendicitis.In adults, the localization of pain is more specific.Sometimes the pain syndrome due to helminthic invasions can imitate "sharp abdomen".
5. Bronchopulmonary.It is most commonly 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 difficult or rough with prolongation of exhalation.With such invasions (ascariasis, strongyloidosis, hookworm) Loeffler's syndrome can be observed.In some infestations (e.g. paragonimosis) 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 host's blood (hookworm), theft from the host (ascariasis, taenia, diphyllobothriasis, etc.), stomach and intestinal dysfunction (taeniarinosis, taenia, 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. The 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 CBC.The degree of its severity depends on the immune status of the patient and the phase of invasion.The acute phase more often than the chronic one occurs with fever and a flu-like condition.The chronic phase is characterized more by subfebrile temperature 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 helminth infestations in humans.

Helminthiasis	Symptoms of infection	Incubation period	Acute phase	Chronic phase
enterobiosis	no	10-15 days	Perianal itching, diffuse abdominal pain, rarely diarrhea, nausea, vomiting.Dysomnia, nocturnal screaming and crying in children.Persistent vulvovaginitis, labia synechiae. The total duration of the infestation 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 high fever, muscle and joint pain, skin rash and itching, signs of bronchitis or pneumonia (eosinophilic infiltrative changes in lung tissue).Broncho-obstruction 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 headache, 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 the invasion is up to 5-7 years).
Diphyllobothriosis	no	Deleted, as the clinical picture of the invasion develops gradually	There is no acute phase as such.Symptoms appear 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 taeniarhynchosis	no	Deleted, as the clinical picture of the invasion develops gradually	There is no acute phase as such.The following symptoms appear and intensify: 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, salivation, nausea, vomiting, rashes such as urticaria, rare damage to the nervous system such as Meniere's syndrome, epileptiform seizures.
opisthorchosis	no	2-4 weeks	Fever, weakness, fatigue, eosinophilia and leukocytosis, pain in the abdomen and liver, 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 girdle (pancreatitis), gradual increase in liver failure.
clonorchiasis	no	2-3 weeks	Same as opisthorchosis, but more pronounced	Same as opisthorchosis.High probability of developing cirrhosis and cholangiocarcinoma
Hookworm and nekatoriasis	2-3 days after infection, a papular or urticarial itchy rash appears at the site of larval penetration, often resembling tortuous 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.Increased temperature, 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 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 implicitly expressed, 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 infrequent stools.Damage to the nervous system in the form of headache, dizziness, fainting.Allergic manifestations - exanthem rashes, urticaria, Quincke's edema, allergic rhinitis.Pale skin with an icteric hue.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 liver failure, secondary cholecystitis and pancreatitis
Strongyloidosis	On 1-2 days, a slight itching and papular rash appears at the site of penetration of the larvae, which quickly disappear.	It is practically absent	On the 3-4th day from the moment of infection, fever, myalgia, joint pain, cough with sputum, wet and dry wheezing appear, bronchial obstruction is possible.X-ray reveals volatile eosinophilic infiltrates (Leffler's syndrome).An allergic skin rash often occurs.	Pain in the epigastric, periumbilical region, less often in the liver, belching, heartburn, nausea, vomiting, loss of appetite and weight, bilious dyspepsia, diarrhea (usually enteritis type, impurities in the feces are rare, usually with massive invasion), hepatomegaly, jaundice.The infestation continues for years due to regular self-infection.
Trichinellosis	There may be abdominal pain, nausea, vomiting, diarrhea	From 1-2 days to 4-5 weeks, average 10-25 days	After the infection, the intestinal phase begins first - abdominal pain, nausea, diarrhea, then generalized - severe muscle pain, swelling of the eyelids, face, less often on the torso, rash according to the type exanthema, in severe cases hemorrhagic, high fever (sometimes subfebrile) for several weeks.	Encapsulation of larvae and their preservation in skeletal muscle for 10 or more years.
Paragonimosis	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 persistent low-grade fever, persistent cough with sputum and blood, hemoptysis, chest pain, dyspnea, 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 your home?

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

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

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;attempts to examine them in stool are futile.
2. Serological reactions, including PCR.

For different infestations, the set of laboratory tests is different.It is important to understand that the standard analysis of feces 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 helminthiases includes prescribing appropriate anthelmintic as well as symptomatic and pathogenetic agents.In this article, we will not go into detail about dosages and treatment regimens for individual helminth infestations;we will only note that the prescription of drugs should be carried out by a doctor (pediatrician, therapist, specialist in infectious diseases, parasitologist) in accordance with the clinical picture, laboratory 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 geohelminthiasis in the general population is low, chemoprophylaxis can be carried out once a year, preferably in autumn or spring. 

Preventive measures

Measures to prevent infection with worms are conditionally 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. Complete processing of vegetables, vegetables and fruits before direct consumption.
3. Refusal to consume raw, poorly processed 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 a specialist in infectious diseases (parasitologist) and recommendations for laboratory diagnostics after returning.The infectious disease specialist also decides on the need for chemoprophylaxis.
7. Avoid swimming in fresh water, walking barefoot or lying 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 OAC, OAM, standard coproovoscopy and scraping for enterobiosis.These events are especially relevant in families with children, adults working in organized children's groups, hospitals, sanatoriums, etc.

Public prevention consists in organizing control over food products offered in shops and markets, timely detection of sick domestic animals and infected people and their treatment.Of great importance is the monitoring of water resources, the improvement of settlements, the assessment of the degree of infection of wild mammals, the control of the limits of natural focal helminthiasis, the number of stray animals.