TOXOPLASMOSIS

TOXOPLASMOSIS is a parasitic disease characterized mainly by the defeat of the nervous system, lymph nodes, muscles, myocardium, eyes, enlarged liver and spleen.

Pathogen - Toxoplasma gondii - intracellular parasite; Refers to the simplest (class of sporovikov), has the form of a crescent, forms cysts. The development of toxoplasm occurs with the change of hosts. The final owner are cats and some other members of the cat family (lynx, puma, jaguar, etc.), intermediate - birds, various mammals (including dogs, farm animals), man. When infecting intermediate hosts, the pathogen penetrates into cells of various tissues, where asexual reproduction takes place. When toxoplasma enters the body of the final host in cells of the epithelium of the intestinal mucosa, asexual and sexual reproduction occurs. The oocysts formed from toxoplasm destroy the epithelial cells and exit into the lumen of the intestine, where sporogony begins. When oocysts are released from the faeces into the environment under favorable conditions, they mature within 2 to 5 days (they become invasive oocysts with the formation of sporozoites in them). Oocysts and sporozoites formed in them are surrounded by a dense two-layered shell, oval in shape and 9 to 14 μm in diameter. Oocysts are able to persist (up to 1 year or more) in the environment. They are resistant to various influences, including disinfectants.

The source of infectious agents in the acquired toxoplasmosis for humans are cats (they disperse feces with oocysts in the environment, pollute the rooms, the hands of people in contact with cats, especially children), as well as mammals and birds infected with toxoplasma, whose meat (less often milk or eggs) is consumed In food raw or not thermally processed.

In addition to the oral route of transmission, it is possible to penetrate the pathogen through the damaged skin during processing of meat and skins of invasive animals (workers of meat-packing plants, fur farms, etc.). Invasive person is not a source of pathogens. Only with congenital toxoplasmosis, the source of infestation for the fetus may be his mother, who suffers from toxoplasmosis.

Acquired toxoplasmosis is the most common zoonosis. In humans, infestation occurs everywhere, but more often in countries with hot and humid climates, as well as among the rural population. In the vast majority of cases, toxoplasmosis occurs as an asymptomatic carrier.

Clinical picture . The incubation period is from 3 to 15 days. More often, infection does not appear clinically. Part of the patients have weakness, pain in the muscles, dyspeptic disorders, malaise. In acute toxoplasmosis, the disease ends with persistent clinical recovery.

In rare cases, generalization of the process is observed. High fever, weakness, chills, headaches are noted. Often there is an increase in various groups of lymph nodes (cervical, axillary, inguinal, mesenteric, etc.). Lymph nodes are dense, painless, with a size of 0.5 to 4 cm. There may be a rose-osseous-papular rash. Increased liver and spleen. In a number of cases, acute toxoplasmosis passes into a chronic, often with lesions of certain organs.

In most clinically expressed cases, toxoplasmosis from the outset takes a chronic course. The disease begins gradually with the appearance of weakness, impaired appetite, sleep disturbance, headache, pain in muscles and joints, subfebrile temperature, irritability. Often there is an increase in lymph nodes. Chronic lesions of various organs and systems can develop : myocarditis , pneumonia , gastritis , enterocolitis , cholecystitis , hepatitis, adnexitis , myositis , encephalitis , retinitis , etc.

In HIV-infected patients there are generalized forms of the disease with CNS and internal organs damage, rapid lethal outcome.

The diagnosis can be made on the basis of a thorough clinical examination and positive results of serological and allergic reactions. From serological studies, complement fixation, passive hemagglutination, indirect immunofluorescence are used. Intracutaneous test with toxoplasmine is widely used. In the blood there are leukopenia , cardiac lymphocytosis, eosinophilia is possible. If suspected of toxoplasmosis, examination of the fundus, x-ray of the skull and affected muscles (presence of calcifications), electrocardiography are necessary.

Treatment . Patients are hospitalized in specialized departments depending on the prevailing organ pathology. As etiotropic therapy, chloride and pyrimethamine are usually used and combined with sulfanilamide preparations. Applied also aminoquinol , hingamin , preparations of tetracycline series. Assign antihistamines, vitamins, restorative products. With chronic toxoplasmosis, a course of immunotherapy with toxoplasmine is administered (intradermally). Persons with asymptomatic carrier of toxoplasm and treatment do not need.

Preventive maintenance: observance of rules of personal hygiene - washing of hands after work (it is especially important at contact to raw meat); Decontamination of meat by roasting (digestion) or freezing at t - 20 ° C. It is recommended to periodically check cats for toxoplasmosis. Do not try raw minced meat; Feed domestic cats raw meat; To allow contamination of soil by faeces of cats; Feces of domestic cats must be destroyed daily to prevent the oocysts contained in them from ripening. It is impossible to keep houses, to feed sick and neglected cats.

Congenital toxoplasmosis develops as a result of intrauterine infection of the fetus from a patient with toxoplasmosis of the mother. The nature of changes in the fetus and the outcome of the disease depend on the intensity of parasitemia developing during pregnancy, the virulence of toxoplasm, the timing of pregnancy at the time of infection, etc. Infection of the fetus can lead to miscarriage, stillbirth, severe damage to the fetal organs, often incompatible with life.

The acute phase of congenital toxoplasmosis proceeds as a severe generalized disease, against which encephalitis often develops . There is an increase in body temperature, chills, weakness, headache , jaundice , enlarged liver and spleen, a variety of rashes, drowsiness, lethargy, decreased muscle tone, strabismus. The disease can take a subacute current as the inflammation processes in various organs subsume. Gradually develop hydrocephalus , changes in the eyes (opacity of the vitreous humor, chorioretinitis). In the chronic phase, there are irreversible changes in the CNS, accompanied by a child's retardation in mental development right up to idiocy, the development of blindness, etc. Congenital toxoplasmosis can last for a long time latently, clinically manifest at the age of 2-7 years and last for many years.

To establish the diagnosis, the results of a mother's examination are important-positive serological reactions in typical clinical manifestations in a child and the detection of a rise in the titers of specific antibodies in it. Treatment is the same as with acquired toxoplasmosis. In the acute phase, specific treatment can lead to complete recovery. Lechenie in the chronic phase is ineffective.

Prevention consists in prevention of toxoplasmosis in women, detection and treatment of pregnant women with fresh toxoplasmic invasion.

All pregnant women with primary treatment in women's consultation are immunologically tested for toxoplasmosis-skin test with toxoplasmin or serological reactions. Pregnant women with positive samples do not need further observation and treatment. In case of negative tests, a second examination in the second and third trimesters of pregnancy is indicated. The appearance of positive samples in this case indicates infection with toxoplasmosis. These pregnant women constitute a risk group and require careful monitoring. When they have a subfebrile condition, lymphadenopathy or other symptoms, an increase in antibody titer, the infectionist and parasitologist should be involved in deciding on the tactics of treatment. If necessary, specific treatment is prescribed only from the second trimester of pregnancy because of the possible teratogenic effects on the fetus. With the development of acute toxoplasmosis in the first 3 months of pregnancy, its interruption is necessary.