Toksokaroz - Causes, Symptoms and Treatment .MF .
Toksokaroz fairly widespread in several countries, some of which Africa, Southeast Asia, Russia, the USA, England, Poland and others.This parasitosis, which is not characteristic of a person, mainly distributed among stray cats and dogs with the carriage of life in the body of the larvae are released into the residential areas with faecal helminth eggs.The average infection rate among his dogs and cats about 16%, however, in some regions up to 90%.In a population of perfectly healthy people positive immunological assays on toxocariasis registered in 5-15% of cases.
Toksokaroz - zoonotic parasitic disease characterized hit (migration) and malicious vital functions in the body of the larvae of roundworms - toxocara, with the possible defeat of the internal organs and systems.
Pathogen toxocariasis toxocariasis
causative agent can be: Toxocara canis (canine roundworms), Toxocara mystax or cati (feline), Toxocara vitulorum (toxocara buffalo, cows).Toxocara are Nemathelminthes type (roundworms), the ge
Eggs toxocara brown (from light to dark shades) are rounded with a dense outer shell, egg size to 65-75 microns (they are larger than those of Ascaris, however, have a similar structure).If the egg is invasive (matured), then inside it is quite mobile larva.If the egg neinvazionnoe (unripe), the larvae inside there, and there blastomere spherical.
Mature form toxocara live mainly in the small intestine and stomach of animals, mostly young dogs, cats and other animals, as well as intermediate hosts.The lifespan of worms by 4 to 6 months.An adult female can lay a day to 200 thousand eggs.Since 1 g of stool of a sick animal can have up to 12-15 thousand. Eggs, it is easy to imagine how many of them is in the soil during defecation.Eggs defecation into the soil, where, under certain conditions (temperature and humidity) to mature for 5-30 days, and mature eggs in the soil can remain viable for several months and even years.
toxocara mature individuals
Short toksokaroza cycle of development of the animal: final host - animal canids (most often) or feline.Infection occurs either by the oral route by ingesting contaminated soil or by transplacental from puppy female.Then there is the life cycle of development or in the main path (canids-soil-canine) or the support path (canids-soil-intermediate host (rodents, pigs, sheep or human). In the second case, a "biological dead end" because the intermediate host(particularly a human) in the transmission of infection is not involved. toksokaroza feature is that there is a full migration toxocara larvae (approximately 5 weeks) to produce mature stage in the gut of an animal and recovering the eggs (this is observed more frequently in young puppies), ormigration in somatic organs (adult animals) and the possibility of infection in pregnant animals of their offspring.
cycle of toxocariasis in humans resembles ascariasis. After ingestion of the eggs to fall into the small intestine, where they come larvae, which through the blood vessels enter theliver, in which a part of them is deposited to form around themselves peculiar inflammatory granuloma. Then, through the inferior vena cava larvae moved to the right heart.Thence the pulmonary artery into the lungs, where again some of them are delayed.From the pulmonary artery remaining larvae penetrate into the pulmonary vein and enter the left side of the heart.Next to a large blood flow to the vessels moves in about 0.02 mm in diameter, which are stuck and are located on the body, which stuck.Consequently, the possible multiple organ pathology (lung, liver, pancreas, muscles, eyes, thyroid, kidney, brain, etc.).In these bodies for a long time (months, years) larvae remain viable.Under the influence of various factors affecting the human immune system, the larvae may once again exercise its migration, which is characterized by recurrent toxocariasis.Toxocara larvae in the human body can survive up to 10 years.Some settled in the bodies of larvae encapsulated (it forms a dense capsule around itself), which are gradually destroyed.Because lung bronchial tree fall in the nasopharynx, esophagus, mature in the gland.
The man toxocara parasitic larval stage only, so the person is not contagious to others.
more dangerous for human larvae toxocara?
main danger larvae toxocara reduced to the emergence of systemic allergic reactions with typical manifestations.Also, given the peculiarity of settling in various organs, and the ability of the formation around it of inflammatory infiltrates - granuloma, there is a risk of violation of functions of the affected organs and systems (liver, kidneys, eyes, thyroid, brain, etc.).We must not forget that settled and "silent" on the face of the larvae with a decrease in the body's defenses can again resume the migration and appear in another body, in violation of its functional state.
Causes of human toxocariasis
source of infection for humans - dogs, especially young puppies, as well as possible other members (for example, a cat that is less common).Man is not a source of infection.
invasion Source at toxocarosis
transmission mechanism - fecal-oral.Infection occurs by ingestion of eggs toxocara in case of direct contact with a sick animal hair, which may be infective eggs, as well as contact with the soil containing the eggs, the consumption of contaminated food.Factors transmission may be dirty hands, unwashed vegetables, fruits, berries, poorly thermally processed meat of an intermediate host - a pig, chickens, lambs, such as contaminated water.There is a possibility of transmission from a pregnant woman to the fetus, as well as breastfeeding, but this path is practically proven.
risk groups during infection toxocariasis:
1) children of preschool age group (3-5 years) playing with sand, soil or a dog;
2) professional groups (veterinarians, breeders, dog breeders, employees of public institutions, drivers, employees of nurseries for dogs, vegetable sellers and department stores, the person having contact with the soil, etc.);
3) The owners of summer cottages, gardens, allotments and kitchen gardens;
4) hunting enthusiasts involving dogs.
Ill mostly children who are playing in the yard (sandbox), with dirty hands swallow eggs.Typical summer-autumn season.
Clinical forms and symptoms of toxocariasis
There are two forms: visceral (systemic) and ocular toxocariasis.
1. Visceral form of toxocariasis (more common in children)
- an acute infectious-toxic syndrome (weakness, lethargy, fever in the afternoon or evening, the body temperature often low-grade - up to 37.50, less febrile - above 380relapses during pulmonary manifestations);
- broncho-pulmonary syndrome (starting with catarrhal symptoms as sore throat and podkashlivaniya until severe asthmatic condition, may be bronchitis, pneumonia, asthmatic cough component (cough with shortness of breath); listened dry, less crackles; radiographically "volatile"eosinophilic or infiltrates;
- liver syndrome (increased liver and seal its pain, in 50% of patients with the combination with the enlargement of the spleen);
- polilimfadenopatii syndrome (swollen lymph nodes of different groups);
- allergy syndrome (urticaria or vesicular eruptions onthe skin in the form of bubbles with clear content);
- abdominal syndrome (abdominal pain, nausea, vomiting, diarrhea, flatulence)
may be destruction:. pancreas (pancreatitis), the heart (myocarditis),
brain (long headpain, epileptiform seizures, paresis, paralysis)
The general analysis of blood:. eosinophilia (70-90%), leukocytosis (15-20 thousand), a slight increase in ESR..With long-term course of patients with anemia (reduced hemoglobin), hypergammaglobulinemia, increased Ig E. The biochemical analysis of blood: may be an increase in bilirubin, increase the activity of enzymes - ALT, AST, GGT.
important enough problem toxocariasis - its relationship with the development of asthma bonhialnoy.A number of scientific studies have shown the identification of antibodies to toxocara in patients with bronchial asthma, as well as improving current asthma therapy after toxocariasis.
2. Ocular toxocariasis (67% of all cases)
develops when non-intensive invasion.Most affected one eye: toxocara penetrate into the choroid, cause inflammation and the formation of specific granulomas in the retina, lens.Can develop endophthalmitis, iridocyclitis, keratitis until the complete loss of vision.
The general analysis of blood: eosinophilia not.Used detection methods toxocara contents special eye element - vitreous.Most often at toxocarosis sided process.
Eye involvement at toxocarosis
fibrosis and retinal detachment at toxocarosis
flow toxocariasis may vary from subclinical and mild to the development of recurrent disease course (months, years), due to the repetitive processestoxocara migrating larvae.
preliminary diagnosis of toxocariasis is exposed on the basis of clinical symptoms zaboelvaniya (allergic reaction, bronchopulmonary syndrome, hepatosplenomegaly, and other), the general analysis of blood (pronounced increase of eosinophils in the peripheral blood, increase in white blood cells, erythrocyte sedimentation rate, decreased hemoglobin), biochemical changes (increased bilirubin, ALT, AST, GGT), increased gamma globulin.
differential diagnosis of toxocariasis is conducted with other helminths - opistorhoz, ascariasis, Hodgkin's disease, vasculitis, eosinophilic granuloma and others.
final analysis exposed after specific laboratory tests.Used serological diagnosis - ELISA reaction to detect specific antibodies - ELISA toksokaroznymi antigens.
Diagnostic titer is 1: 400.Titers below 1:400 (1:100, 1:200), especially in the absence of symptoms regarded as a sign of invasiveness, but not having the disease at present (note about the ability and capability toxocara encapsulated inside the capsules die, which will also be accompanied by circulating antibodiesblood within a certain time).In this case, the prescribed treatment will not bring the desired effect, titles will remain the same.The titer of 1: 200 can also indicate remission (recovery) visceral toxocariasis for several months after treatment.
titers 1: 200-1: 400 may indicate the presence of toksokaronositelstva (carrier encapsulated larvae).
titer of 1: 400 points to the probable eye toxocariasis or visceral toxocariasis remission after treatment in the first weeks.Institution of therapy should be weighed and proven clinical symptoms of the disease.
titer of 1: 800 or more points on the incidence of visceral toxocariasis, which is an absolute indication for treatment.
should not forget about the possibility of recurrence of the disease, so a particular patient antibody titers can vary and fluctuate.False-positive reaction for antibodies to toxocara can be identified: in patients with lymphoproliferative diseases of systemic nature, the gross violations in the immune system.Final verification of the diagnosis also requires the detection of larvae in biopsy tissues (most often it succeeds in lesions of the liver).
Specific (antiparasitic) treatment appoint a doctor in the presence of strict indications (symptoms, changes in blood count, high titer ELISA reaction).Drugs are effective only when migrating larvae observed weak efficiency in the presence of granulomas in the tissues and no migration.
as antiparasitic treatment used drugs albendazole (zentel, nemozol), mebendazole (Vermoxum, vormin), thiabendazole (mintezol) medamin.Treatment courses of 10 to 30 days depending on the form of the disease and the drug selected.Treatment for 3-5 courses with an interval of 3-4 months (2 months is possible with sustained reduction in the titer of antibodies).Performance criteria: reduction of eosinophils, the antibody titer, the symptoms subsided.
In order to intensify the treatment prescribed symptomatic therapy: gepatoprotektory (Essliver, Kars, gepatrin and others), antihistamines (Claritin, zodak, zirtek, tsetrin, erius and others), non-steroidal anti-inflammatory drugs (diclofenac, indomethacin, ibuprofen, etc.),expectorants, enteroseptiki, immunomodulators, and others.
forecast toksokaroza generally favorable.Fatalities are rare in the case of intensive invasion, the absence of remedial measures.
In the case of ocular toxocariasis prognosis depends on the severity of the changes.If infitsiroaniya small as possible, and there is an active infection (ie, there is an active migration), there is a chance the drug effects on larvae and regression of the inflammatory process in the organs of vision.If there is a central location of the lesions and the formation of fibrosis prognosis in terms of visual functions adverse changes irreversible.
Prevention of toxocariasis
Preventive measures related to the sanitary education of children, learning hygiene skills the younger generation.One of the areas of prevention - timely examination and deworming dogs.Protection of children's playgrounds, sandboxes from visiting animals, their good insolation (illumination of the sun).
infectious disease doctor Bykov NI