Toxocariasis - a parasitic disease caused by the larvae of Ascaris. It characterized by a prolonged course and multiple lesions of the internal organs.
Sexually mature forms toxocara - large dioecious worms length of 4-18 cm are located in the stomach and small intestine of animals (dogs). The intensity of infection in dogs can be very high, especially in young animals. The average life span of mature individuals of 4 months, the maximum - 6 months. The female parasite lays per day, more than 200 thousand. eggs. In 1 g of faeces can contain 10,000-15,000 eggs, so that the soil get millions of eggs, thus causing a high risk of toxocariasis infection.
mechanism of infection
the development cycle of the pathogen as follows: Isolated eggs toxocara into the soil, where, depending on the humidity and temperature of the soil mature in 5-36 days, becoming infectious. Infectiousness of the eggs stored in the soil for a long time, the compost - a few years.
toxocara complex life cycle. Allocate main loop and two subsidiary embodiment. The main loop occurs according to the scheme: the final host (dog) - soil - the final host (dogs). Auxiliary cycle (option 1) is transplacentally, in this case in the larval stage parasite passes from the fetus of a pregnant female. Infected puppy becomes a full-fledged functional definitive host, the source of infection.
Auxiliary cycle (option 2) is carried out by Chains final host (dog) - soil - a reservoir host. Reservoir host may be rodents, pigs, sheep, birds, earthworms. The person also acts as a reservoir host, but is not included in the transmission cycle of infection, as a parasite biological dead end. Further development of the pathogen occurs under the condition that the reservoir host is eaten by a dog or other definitive host.
In humans, the development cycle of the pathogen, its migration as follows. Egg toxocara caught in the mouth, then the stomach and small intestine larvae that penetrate through the mucous membrane in blood vessels and through the portal vein migrate to the liver where some of them are deposited, surrounded inflammatory shell. Part of the larvae of the hepatic veins of the liver system passes the filter falls into the right heart, through the pulmonary artery - lungs. In light of the larvae is also delayed, and some passing light filter according to the systemic circulation is stored in various organs, settling in them. Toxocara larvae can be localized in various organs and tissues - kidney, muscle, thyroid gland, brain and others. In the tissues of larvae remain viable for many years and from time to time, under the influence of various factors, migration resumed, causing a relapse.
Toxocariasis - a widespread disease, it is registered in many countries.
The main source of infection for humans are dogs, especially puppies. Toxocariasis Infection occurs through direct contact with infected animals, wool is contaminated eggs, or if it enters the mouth of the earth, in which were toxocara eggs. Particularly susceptible to infection with the children while playing in the sand or with a dog. Adults infected by casual contact with infected animals or during professional activities (veterinarians, breeders, municipal service workers, drivers, diggers etc.). In humans, infection is possible also by eating raw or poorly treated thermally meat. There are cases of toxocariasis infection by eating lamb's liver.
manifestations of toxocariasis
Symptoms of infection toxocarosis determined intensity distribution of larvae in organs and tissues, especially human immune response. Manifestations of toxocariasis is not specific and are similar to other worms.
Toxocariasis usually develops suddenly or after a brief pre-disease manifests itself in the form of lung ailments. It appears temperature - low in mild cases and higher to 39 ° C and higher, sometimes with chills. skin rashes may occur in the form of urticariaSometimes the swelling type angioneurotic.
In the acute phase observed pulmonary syndrome varying degrees of severity from mild to phenomena acute bronchitis, pneumonia, Severe asthma attacks. Especially severe pulmonary syndrome occurs in young children. Sometimes there is pain in the stomach attacks.
There have been cases of thyroid lesions, manifested symptoms of the tumor. When the larvae migrate to the brain: Thrust headache, Convulsions, paralysis.
In children, the disease is accompanied by weakness, mild irritability, sleep disturbances.
Diagnostics
The most typical laboratory toxocarosis index is increased content eosinophils in the peripheral blood. The relative level of eosinophilia can vary within a wide range, reaching 70-80% in some cases more. Increased content of leukocytes. In the chronic stage of the disease acute clinical and laboratory signs of decay. Most stable laboratory indicators remain elevated eosinophils.
Parasitological diagnosis is rare and only by the presence of tissue specific entities - granulomas and larvae and their identification in the study of biopsy and section material. This is possible when biopsy of the liver, lungs, surgical intervention. Use as immunological reactions allow the detection of antibodies to antigens toxocara. Typically used ELISA excretory-secretory antigen toxocara second instar larvae.
Find diagnostic titer antibody titer of 1: 400 and higher (ELISA). The antibody titer of 1: 400 indicates the infection but not disease. The antibody titer of 1: 800 or higher indicates toxocariasis disease. Practice has shown that a direct correlation between antibody levels and the severity of the clinical manifestations toxocarosis does not always exist.
toxocariasis treatment
toxocariasis treatment developed enough. Applied mebendazole (Vermoxum) medamin. These drugs are effective against migrating larvae and are not sufficiently effective against tissue forms, which are in the granulomas of internal organs.
Vermoxum (mebendazole) 200-300 mg administered daily for 1-4 weeks. Adverse reactions are usually not observed.
Medamin used in a dose of 10 mg / kg of body weight per day by repeated cycles of 10-14 days.
Albendazole is administered in a dose of 10 mg / kg of body weight per day, in two divided doses (morning, evening) for 7-14 days. During treatment toxocarosis necessary control and blood analysis aminotransferase (toxic effect of the preparation on the liver).
Criteria of efficacy of treatment: improvement of the general condition, a gradual reduction of the manifestations of toxocariasis, reduction of eosinophilia and specific antibody titers. It should be noted that the effect of treatment ahead of the positive dynamics of the changes in the blood. In recurrent clinical symptoms, persistent eosinophilia and positive immunological reaction is carried out repeated courses of treatment.
Prediction and prevention
Forecast at toxocarosis favorable for life, but in a massive infection and severe lesions of internal organs, especially in patients with impaired immunity, death is possible.
Prevention of toxocariasis includes personal hygiene, sanitary education of children skills. An important preventive measure is the timely examination and deworming dogs. The most effective treatment of puppies in 4-5 weeks of age, and pregnant females.
