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Toxocariasis in adults is a parasitic disease that belongs to helminthic invasions. Among adults, this infection ranks first in terms of prevalence, and in children - second after enterobiasis. Antibodies to the causative agent of this helminthiasis were detected in 28% of the population, which speaks volumes about the infection of a third of the adult population. The number of infected people is especially increasing in rural areas, since there people are more in contact with animals, which are the sources of the disease. When examining domestic cats and dogs, the causative agent of the disease was detected in 30% of adult animals, and in newborn puppies and kittens this percentage is even higher.
- Toxocariasis - a description of the disease
- Infection routes
- Forms and symptoms
- Visceral form
- Eye shape
- Cutaneous form
- Neurological form
- Toxocariasis treatment
Toxocariasis - a description of the disease
Toxocariasis is caused by roundworms of the nematodes from the Toxocar class, which primarily affect mammals from the canine genus: wolves, foxes, raccoons, dogs, polar foxes. The length of the male toxocara is from 4 to 10 cm, in females it is 7–8 cm. In the body of their main host, they rapidly multiply, releasing millions of eggs into the environment. Toxocara female lays up to 200 thousand eggs per day, which are released into the environment, spreading and spreading everywhere. Each egg contains a live larva, which is protected by a multilayered strong shell. Thanks to the protective shell, toxocar eggs can maintain their viability for a long time in anticipation of a potential host and favorable conditions for their development.
There are two types of toxocara:
- Toxocara canis, a parasite in the dog's body;
- Toxocara cati, a parasite in the intestines of cats.
Animals both at home and in the wild become infected by eating small rodents, insects, food in garbage containers, and by licking objects on the ground. It is known that more than 40% of the soil is contaminated with toxocara eggs. In many dogs, toxocariasis is a congenital disease, as puppies become infected through the placenta already in the womb or through milk during feeding. In the future, toxocars are localized in puppies in the intestines and are excreted with feces into the environment.
The development cycle of Toxocara involves two hosts: one intermediate and one main. Sick animals, most often dogs, are the source of infection. Through dirty hands, after contact with an animal, toxocara eggs are swallowed by humans. Once in the small intestine, the larvae are released from the eggs and absorbed through the intestinal wall into the bloodstream. With the blood flow, they migrate throughout the body, causing at this time the strongest allergization of the body. The spectrum of their migration is quite wide; together with the blood flow, they enter the liver, lungs, brain, kidneys, eyeball, bile ducts, and pancreas. They can settle in organs and tissues, become covered with a capsule and remain viable in this state for 10 years. Then, for whatever reason, the larvae of the parasite are activated,continuing migration to other organs and systems. Such movement of larvae does not pass without leaving a trace for the body. At the site of their invasion, traces remain in the form of necrosis, inflammatory processes and injured tissues.
A person is not a source of Toxocara infection, since adults do not develop in his body and the eggs of this helminth are not released. The source of infection is dogs. It is they who secrete toxocar eggs with feces, since a full development cycle of these parasites occurs in their body.
Canine ascariasis and human ascariasis should not be confused, moreover, these two diseases should not be confused with toxocariasis, the causative agent of which is the parasitic worm Toxocara canis.
Dogs are not always the source of infection. You can also get infected through food, after eating poorly washed vegetables, herbs, berries and fruits, through water and as a result of banal non-observance of personal hygiene rules.
There are factors that contribute to infection with this helminthiasis:
- contact with contaminated soil with robots in the garden, playing with a child in a sandbox;
- eating poorly washed vegetables, herbs, berries and fruits;
- the use of low-quality drinking water;
- contact with animal hair;
- cases of picacism (the desire to eat inedible objects) in this case, eating clay, earth, chalk, sand;
- non-compliance with the rules of personal hygiene (dirty hands);
- labor activity, people are infected whose labor activity is associated with cleaning the streets, working with dogs, land, hunting, etc.;
- contact with the excrement of cockroaches, which eat Toxocar eggs;
- the implementation of the act of defecation by animals on the street, stepping on the stool, you can bring them into the house with shoes.
Statistical data indicate a high degree of infection among socially unprotected people with poor living conditions and a lack of utilities.
Forms and symptoms
According to the degree of its course, the disease has the following forms:
- latent form - without visible symptoms and with good health;
- erased form - with poorly expressed symptoms and a slight deterioration in well-being;
- manifest form - with pronounced symptoms and poor health.
As a rule, adults suffer from a latent or erased form of toxocariasis. In addition, this helminthiasis can occur in both acute and chronic forms. In this case, acute stages are replaced by stages of remission. The exacerbation phases are characterized by the fact that the larvae constantly migrate through the body to new organs and cause new manifestations of the disease.
Symptomatic forms of toxocariasis:
- visceral form;
- neurological form;
- ocular form;
- cutaneous form.
The most common form of toxocariasis, which is diagnosed in most cases of infection. With this form of the disease, toxocara larvae affect the internal organs. Depending on where the parasite is located, symptoms of the disease develop. The larvae migrate in the body with the blood stream and settle where the blood circulation is not too intense.
When toxocara eggs enter the gastrointestinal tract, they are resettled in the small intestine, liver, pancreas and bile ducts. In this case, there are violations in the liver, a violation of the outflow of bile, damage to the intestinal walls, the release of pancreatic enzymes is disrupted. All this is accompanied by the following symptoms:
- weight loss;
- pain in the liver and pancreas;
- constipation and diarrhea;
- loss of appetite;
- bitterness in the mouth;
- nausea and vomiting after eating;
- headaches and tinnitus;
- the development of anemia.
When the pulmonary system is damaged, the following symptoms are observed:
- dry cough;
- frequent bronchitis;
- gasping for breath;
- catarrhal phenomena;
- asthmatic breathing;
- broncho - pulmonary infiltration;
- swelling of the limbs and abdomen;
- asthma attacks with blue skin around the nasolabial folds.
This form of toxacorosis is extremely rare. With the ocular form, only one eye is affected, most often with one single larva. On visual observation, movement of the larva can be seen. In case of damage to the optic nerve by the larva of toxacorosis, a person will be completely blind in one eye.
Symptoms of the ocular form of toxacorosis:
- bulging of the eyeball;
- redness of the conjunctiva;
- swelling of the eyelids;
- pain in the eyeball;
- hyperemia of the orbit.
Eye damage causes the development of the following diseases:
- granulomas of the eye;
- optic neuritis;
- vitreous abscess.
With this form of toxocariasis, the migration of larvae in the thickness of the skin is observed. The skin form manifests itself with the following symptoms:
- itchy skin;
- sensation of a foreign body under the skin;
- redness of the skin;
- hyperemic traces in the direction of movement of the larvae.
This form develops when the larvae are localized in the brain. In this case, the central nervous system, the lining of the brain and its tissues are affected.
Symptoms of the neurological form:
- epileptic seizures;
- unsteady gait (violation of the vestibular apparatus);
- fainting and coma;
- violation of consciousness;
- headaches and dizziness;
- nausea and vomiting;
- muscle weakness;
- aggressiveness and nervousness.
A combination of different forms of toxocariasis is extremely rare.
It is extremely difficult to identify toxocariasis only by clinical manifestations. It is impossible to find the eggs and larvae of the parasite in the feces, since there are no eggs at all in the human body, and the larvae do not live in the large intestine. It is impossible to isolate the Toxocar larvae from the tissues into a living one, since such a procedure would be very painful and traumatic.
The only effective diagnostic method is an enzyme-linked immunosorbent assay (ELISA), testing a patient for specific antibodies. This analysis allows not only to accurately determine the presence of a parasitic infection in the body, but also to identify the type, number of parasites and the extent of the lesion. Today ELISA test is the most accurate diagnostic method.
According to the test results, the analysis results are decoded. It is also necessary to conduct a number of additional studies in order to find out the degree of damage to the body by this parasitic infection.
For this purpose, the following studies are carried out:
- biochemical blood test - the level of blood components is determined;
- general blood test - the level of eosinophils and leukocytes is determined, as well as the level of hemoglobin, the acceleration of ROE;
- sputum examination - with pulmonary (visceral) form of toxocariasis, microscopic examination of sputum determines the presence of larvae in the lungs and respiratory tract;
- ultrasound examination (ultrasound) of the abdominal cavity - determines the size of the liver, spleen and pancreas, as well as the presence of inflammatory processes in these organs;
- chest x-ray - captures the appearance of infiltrates that move over time;
- computed tomography (CT) - determines the presence of infiltrates with faces in the brain)
- magnetic resonance imaging (MRI) allows you to notice changes in infiltrates containing larvae.
- ophthalmoscopy - detection of foreign objects during eye examination.
Confirmation of the diagnosis may be the presence of a dog in the house, living in a rural area, frequent contact with the land, the specifics of professional activities.
To date, there is no specific treatment regimen for this helminthic invasion. For the treatment of toxocariasis, the following drugs are used:
- Vermox. Assign 100mg 2 times a day for 2-4 weeks. Minor side effects such as headache and nausea are possible. Such effects are extremely rare.
- Mintezol. Assign 50 mg per 1 kg of body weight 1 time per day for 5-10 days. Short-term side effects may occur.
- Ditrazine. Prescribe for 2-4 weeks 1 time per day for 4-6 mg per 1 kg of weight. Side effects such as fever, headaches, dizziness, nausea and diarrhea are possible.
- Nemozole (Albendazole). The drug is prescribed for 10-20 days, 1 time per day, 10 mg per 1 kg of weight. Side effects are observed in the form of nausea, diarrhea, and abdominal pain. Contraindication: pregnant women.
In severe advanced cases, the treatment of toxocariasis is carried out in a hospital. With a latent or latent form of helminthiasis, treatment is carried out on an outpatient basis. With the mass death of larvae, a strong reaction of the immune system occurs in the form of allergization of the whole organism. For this reason, the treatment is supplemented with antihistamines, which are designed to eliminate the immune response. During the treatment period, it is important to follow a diet that excludes brightly colored vegetables, wine, citrus fruits, spices and cheese.
Treatment of toxocariasis involves the use of drugs that improve the functioning of the digestive system and restore the body.
In the future, the body is restored in the following areas:
- the clinical manifestations of toxocariasis regress: fever, intoxication, allergy, respiratory failure;
- the level of eosinophils in the blood formula decreases;
- the level of antigens to toxocariasis in the blood serum decreases.
If control laboratory tests show a slight improvement, then after 3-4 months the course of treatment is repeated. With massive helminthic invasion, up to five courses of anthelmintic therapy are required. Sometimes such treatment is carried out in a hospital setting. This disease has a favorable course and outcome, in rare cases, with damage to vital organs, a lethal outcome is possible.
After recovery, the human body develops local immunity against toxacorosis reivasia.
In the development of this helminthiasis, compliance with the rules of personal hygiene is of great importance, which are as follows:
- frequent hand washing after contact with soil, with animal hair;
- thorough washing of herbs, vegetables, berries and fruits that may contain soil particles;
- toxocariasis eggs are covered with a special sticky agent, so you can remove them from objects, vegetables, herbs, fruits only with a special detergent;
- monitor the quality of the water used in food, subject it to high-quality heat treatment;
- protect children's playgrounds from stray cats and dogs.
The preventive measures carried out by the medical and veterinary service are as follows:
- Preventive measures aimed directly at the source of infection. In this case, stray dogs are dewormed, as well as dogs during pregnancy.
- Limiting the number of stray individuals, the allocation of specialized areas for walking pets.
- Preventive treatment of puppies, regular examination of dogs and their treatment in case of detection of toxocara.
- Measures to prevent the development of infection. This includes following the rules of personal hygiene.
- Carrying out educational work in order to familiarize the general population about the ways of transmission of infection and about safety measures.
- Informing persons who are at risk. As a rule, the risk group includes people who, due to their professional activities, have contact with animals, dust and soil.