Toxocarosis: symptoms and treatment of a person, waysinfection, forms, prevention

Update: December 2018

Toxocarosis is the damage of human tissues and organs by the larvae.
parasitic worm (helminth) toxocaras Toxocara canis.
The disease is widespread in our country and
takes in the structure of helminths one of the first places.

Toksokaroz refers to geohelminthiasis (“geo” – land), because
microscopic eggs with helminth embryos ripen and lasting
time saved in the earth. Toxocara’s natural host is
carnivores from the dog family (dogs, wolves, foxes) and
felines (cats), they get to humans by mistake and not
develop to adult forms.

The disease proceeds with so diverse manifestations
that even experienced doctors do not make a diagnosis based on the clinical
the pictures. Toxocara larva migrates in the human body with current
blood vessels and can fall into any organs, and this will be
caused by appropriate symptoms.

Often, toxocarosis occurs according to the type of allergic reaction in
form of urticaria, bronchial asthma, angioedema. Suspect
the presence of a helminth allows a complete blood count, after which the doctor
assigns confirmatory studies. Adequate therapy relieves
patients from serious health problems that often over the years
not amenable to standard treatment.

The causative agent and its transmission

Toksokara – a parasitic worm from the class of roundworms or
nematodes (Nematoda).

  • Most often, a person is affected by a dog toksokar (dog
    Ascaris, Toxocara canis)
  • In rare cases, cat becomes the causative agent of toxocariasis.
    toxocara (cat’s roundworm, Toxocara mystax).

Externally, parasites are similar to human ascaris, as they
close relatives: they are connected by the same type of structure, cycle
development, migration of larvae. However, the final owners of them
differ, so they cause different diseases in the clinic.

Tokokara has white color, the extended body in the form of thin
cylinder with pointed ends. The length of the female is 6.5-10 cm,
males are smaller and on average have a length of 4 to 6 cm. Adults
individuals live only in the stomach and intestines of a dog or cat,
man they do not meet.

Parasites accidentally entering the human body by the host
which are other animals, cause severe damage
internal organs, since they are not adapted for life in
similar conditions. They cannot complete the development cycle and go into
safe for the owner form.

The parasite always strives to be invisible to its host,
therefore causes minimal changes in his body, barely
perceptible symptoms. The worm is interested in its environment
habitat for a long time supplied it with nutrients and
remained viable, therefore invasion (interaction
helminth with a man) usually proceeds benignly.

Infection of animals occurs in the following ways:

  • when eating feces of other animals, soil contaminated with eggs
  • при поедании крыс, мышей, зараженных личинками toxocars;
  • during pregnancy the larvae penetrate the placenta bitches in
    developing puppies;
  • when ingesting puppies with milk from a mother infected with larvae

Egg toksokary enters the dog / cat’s stomach, where under
the action of gastric juice its outer dense shell
splits and the larva comes out. She reaches thin
intestine, punches its wall and enters the blood
vessels With the flow of blood, the larva sequentially passes through:

  • liver veins;
  • inferior vena cava;
  • right atrium and ventricle;
  • lungs;
  • left parts of the heart;
  • a large circle of blood circulation, from which it is deposited in any

In normal animals, the larvae settle in the lungs, not reaching
a large circle of blood circulation. They are carried with mucus down the throat and
swallowed by the dog, re-entering the gastrointestinal
tract. In the small intestine, the larvae reach maturity and
begin to multiply. Eggs are excreted with animal feces.
They enter the soil where they ripen within 1-4 weeks and
become infectious for the next hosts.

A person becomes infected in the following ways:

  • by ingesting toxocary eggs from animal fur;
  • by eating vegetables contaminated with soil, fruits,
  • when eating land (typical for children and mentally ill

Infections are most susceptible to young children, since they do not
сформированы навыки personal hygiene. Usually infection occurs in
warm season, as during this period, human contact with the earth
occur quite often. Often toxocarosis occurs in people
employed in agriculture, mentally ill, in
unscrupulous families.

Cockroaches play an important role in the transmission of toxocariasis. They eat
helminth eggs and secrete them in a viable state in the home
people on food, which leads to infection of people.

In humans, toxocara larvae always go into a large circle
blood circulation and deposited in the organs into which they manage to penetrate
through the vascular wall. The larva falls into the wrong for her
environment, so it is covered with a dense capsule and goes into
inactive form. As such, it can be stored in the body.
person for years. Its further advancement is impeded by cells.
immune system that form around the larvae inflammatory
the barrier. Any reduction in immunity leads to activation
helminth and exacerbation of the disease.

Classification and symptoms of the disease

Toksokaroz proceeds in various forms:

  • manifest – with clear clinical signs;
  • erased – with minor non-specific symptoms;
  • latent – without any manifestations visible during the inspection
    sick, disturbing him.

The severity of the disease depends on age:

  • Toxocarosis in a child under 12 years old proceeds in manifest –
    severe or moderate form
  • in adults, symptoms of toxocariasis are either erased or absent

Если заболевание длится меher 3-х месяцев, его называют острым,
if more – chronic. In chronic toxocariasis, periods
asymptomatic course (remission) are replaced by exacerbations, during
which the larvae resume their migration and cause a new wave
clinical manifestations.

According to clinical manifestations, the following forms are distinguished.

  • visceral (with damage to internal organs);
  • eye;
  • dermal;
  • neurological.

Regardless of the localization of the larvae in the body, their presence
activates cells of the immune system, makes them more aggressive.
They are set to fight the parasite, which often results in
allergic reactions by type:

  • Skin eruptions – its elements resemble bites in appearance.
    mosquitoes, can be ring-shaped, located on any parts
    body. Accompanying itchy rash of varying severity: from
    slight discomfort to complete loss of rest.
  • Swelling Quincke – it is localized in the neck, squeezes
    larynx, which prevents the passage of air into the lungs. In man
    there is a sudden attack of suffocation, he cannot breathe air and
    completely выдохнуть, кожа его сиherт. Without emergency medical
    aid angioedema often results in the death of a person.
  • Bronchial asthma – manifested as a long dry
    cough with a small amount of light sputum, bouts
    shortness of breath and choking during which a person cannot do full
    exhale The breath of the patient during the attack becomes so
    noisy that dry rales are heard at a distance from him.

Acute form of toxocariasis and exacerbation of chronic is often
accompanied by fever, the patient’s body temperature rises to
37-38 degrees C. Symptoms of intoxication: weakness, headache,
lack of appetite, aches in muscles and joints expressed
незначительно или отсутствуют completely. On the presence in the body
parasite lymph nodes react – five or more of their groups increase in
sizes, but remain painless and mobile (without signs of

Visceral form

90% of cases of disease occur with internal lesions
organs. Symptoms of toxocariasis in this case are directly related
with the system affected by the larvae, while combined with
manifestations of allergies and intoxication. As stated above,
the parasite travels through the human body with a blood stream, therefore
it most often settles in organs with an extensive network of blood
vessels and relatively slow blood flow: in the liver, lungs,
the brain.

The defeat of the digestive system begins with
penetration of larvae into the liver tissue. Next, they fall into
biliary ducts, pancreatic ducts, 12
duodenum, small intestine. Thus, the larvae violate
outflow of bile and pancreatic juice, injure intestinal
wall, which is manifested by the following symptoms:

  • heaviness in the right hypochondrium;
  • stitching right under the ribs;
  • bloating;
  • flatulence;
  • bitter taste in the mouth;
  • stool disruption: alternating constipation with diarrhea;
  • nausea after fatty foods;
  • stomach ache;
  • потеря массы body.

Toxocar can mechanically damage the intestinal wall, leading to
constant small blood loss that is clinically manifested
anemia (decrease in hemoglobin in the blood), weakness, pallor of the skin
and mucous membranes, tinnitus.

Поражение дыхательной системы manifested:

  • persistent dry cough without sputum or with little
  • shortness of breath;
  • difficulty exhaling;
  • attacks of suffocation.

Subsequently, toxocarosis leads to the development of a complete
bronchial asthma, sometimes causes severe pneumonia,
pulmonary edema.

In some cases, when passing through the chambers of the heart of the larvae
deposited on the heart valves, which leads to the development of endocarditis.
Valve damage interferes with normal hemodynamics, clinically
it manifests itself as heart failure:

  • weakness;
  • the bluish tint of the skin of the fingers, nasolabial triangle;
  • shortness of breath and cough when lying down if the left one is damaged
    half heart;
  • symmetrical swelling in the legs and stomach if the right one is damaged
    half heart

Eye Form (Ophthalmotoxocarosis)

A rather rare form of the disease, develops with lesions.
the larvae of the toxocara of the orbit of the eye, its muscles or internal structures
eyeball. In this case toxocarosis in humans

  • severe vision loss, complete or partial, more often than one
  • conjunctival redness;
  • bulging of the eyeball;
  • swelling and hyperemia of the eyelids, the tissues of the orbit;
  • bursting pain in the orbit;
  • squint.

The eye form of the disease mainly affects children, with
this allergic symptoms and general intoxication they have not
are expressed.

Skin form

The larvae migrate directly in this case.
дерме кожи, что manifested:

  • skin itching, burning, pain;
  • sensation of movement under the skin;
  • red inflamed marks of movement appear on the skin
  • inflammation of the skin in the area of ​​invasion.

Neurological form

The penetration of the larvae of toxocara through the blood-brain
the barrier leads to inflammation of the meninges and brain tissue.
The disease is severe and manifests symptoms.
neurological disorders:

  • severe headache arching nature;
  • agonizing nausea, vomiting fountain;
  • tension of the muscles of the neck and back;
  • hypersensitivity to sound, light,
  • muscle weakness of the limbs or their complete paralysis;
  • convulsions;
  • disturbance of consciousness up to coma;
  • staggering gait, loss of balance;
  • mental disorders (aggressiveness, reduced intelligence,
    developmental delay in children).


Diagnosis of toxocariasis is done by doctors of various
specialties depending on which organ system
affected in humans and with what symptoms he turned into a curative
institution Suspect worm infestation allows them to:

  • clinical blood count, which is significantly increased
    the number of eosinophils – the blood cells responsible for
    antiparasitic immunity.
  • the next step in the diagnosis of toxocarosis is
    determination of total immunoglobulin E in the serum of venous blood,
    which will also be upgraded.

In most cases, patients with eosinophilia and with increased
the concentration of immunoglobulin E is sent for consultation to
infectious diseases Damage to internal organs and systems, allergic
manifestations, an increase in lymph nodes lead the doctor to the idea of ​​tissue
helminthiasis, one of which is toxocariasis. Diagnosis
toxocariasis in adults and children is indirectly confirmed by
detection of specific immunoglobulin E to toxocara in
serum. Direct confirmation of the diagnosis is detection
the larvae themselves in the patient’s tissues, which is impossible or traumatic in
most cases.

In favor of toksokaroza says the presence of a human dog
household plot, farm, non-compliance
personal hygiene. Among the research methods are informative

  • complete blood count – in addition to eosinophilia, it is detected
    increase in the total number of leukocytes (leukocytosis), accelerated ESR,
    decrease in hemoglobin concentration and red blood cell count
  • biochemical blood test – with toxocariasis observed
    increased levels of total protein, amylase, AST, ALT,
    gamma-glutamyltransferase, alkaline phosphatase, C-reactive
  • microscopic examination of sputum – with the defeat
    respiratory system in it are detected toksokar larvae;
  • chest x-ray – the larvae in the lungs lead to
    eosinophilic infiltrates – areas of lung tissue with increased
    density, which is well traced in the pictures. Their feature is
    migration of infiltrates in the lung fields at each subsequent
  • Ultrasound of the abdominal organs – allows you to detect an increase
    the size of the liver, spleen, inflammation of the gallbladder and
  • ECHO-KG – with toxocariasis with valvular heart disease
    ultrasound can assess the hemodynamics and severity of damage;
  • Computed or Magnetic Resonance Imaging – Examine
    internal organs, central nervous system for detection
    specific inflammatory areas within which are enclosed
  • ophthalmoscopy – examination by the ophthalmologist of the internal media of the eye,
    what allows to reveal foreign particles in them;
  • measurement of visual acuity – in case of ophthalmocarcosis
    of the affected eye is sharply reduced, healthy – remains on
    former level.


Treatmentм токсокароза занимается врач-инфекционист совместно с
doctors of other specialties, if there is a lesion:

  • eye – with an ophthalmologist;
  • nervous system – with a neurologist;
  • perforation of the intestinal wall – with the surgeon.

With erased and latent course of the disease, therapy is carried out in
outpatient conditions, with manifest toxocarosis treatment in children
carried out in the hospital. Adults hospitalization indicated
with the development of severe complications.

All patients are prescribed a hypoallergenic diet to reduce
activity of the immune system and the prevention of allergic reactions.
From the diet should be excluded brightly colored foods, citrus,
chocolate, cheese, wine, marinades, smoked meats, spices.

For drug treatment of toxocariasis in adults and children
use groups of drugs presented in the table.

Type of therapy Drugs
Etiotropic – directly affects the cause of the disease –
toxocara larvae causing its death
  • Mebendazole – used in children older than 2 years and in adults
    (See the review of the worms tablets)
  • Albendazole – approved for use in patients after the first
    years of life.
Pathogenetic – restores the processes broken by a disease
in the body or stops their further development
  • Glucocorticoids (prednisone, dexamethasone) – have powerful
    anti-inflammatory and anti-allergic effects.
  • Electrolyte solutions (saline, potassium chloride, sodium acetate)
    – are administered intravenously in severe forms of toxocariasis for
    elimination of symptoms of intoxication.
  • Drugs лакто- и бифидобактерий – восстанавливают кишечную
    microflora for stool normalization in visceral form
  • Adsorbents (smekta, enterol) – they are taken orally for removal
    from intestinal toxins.
Symptomatic – facilitates the patient’s condition, but does not affect
neither on the cause of the disease nor on its course
  • Antipyretic (ibuprofen, paracetamol) – normalize
    body temperature, eliminate muscle aches and joints.
  • Antispasmodics (drotaverine, papaverine) – relieve abdominal pain
    with spastic contraction of the biliary tract.
  • Antiemetic (metoclopramide, domperidone) – normalize
    motility of the gastrointestinal tract, stop vomiting.
  • Antiallergic (cytirizine, ketotifen) – eliminate dermal
    itching and rash.

Criteria for recovery are:

  • normal body temperature for more than 3 days in a row;
  • lack of intoxication;
  • lack of allergic manifestations;
  • normalization of respiration;
  • normalization of blood counts;
  • reduction in the number of specific antibodies to toxocars in
    serum of the patient (4 times 3-4 months after

After discharge the child observes the local pediatrician in
for 12 months with visits every 2 months. His
Medotvod from vaccinations and physical education for 1-3 months is shown in
depending on the severity of the disease.


Prevention токсокароза заключается в пресечении путей передачи
Toxocara eggs:

  • personal hygiene;
  • de-worming domestic dogs and cats at least 2 times a
  • ban on dog walking at playgrounds, in
  • fight against cockroaches;
  • eating only greens washed with running water,
    vegetables, berries.

The incidence of toxocariasis is directly related to the number
infected dogs, therefore measures are needed to reduce the number
stray animals and careful monitoring of domestic health.

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