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Laboratory diagnosis of tissue helminthiases



Laboratory methods for tissue helminthiases, as a rule, are crucial for making and registering a diagnosis and selecting rational etiotropic therapy. In connection with the peculiarities of the pathogenesis of the described diseases, the methods of coprological research used to diagnose intestinal helminthiases are not informative. Currently, there are parasitological, immunological, including serological, and genetic engineering methods for diagnosing parasitoses. The most affordable and effective for all migratory larval helminthiases is the serological diagnostic method.

Serological method. With trichinosis, serological reactions become positive only in the third week of invasion, which makes them useful in the late stages of manifest forms of the disease and for the diagnosis of atypical forms of invasion. An enzyme-linked immunosorbent assay (ELISA) is most often used, a titer of 1: 100 is considered diagnostic, less commonly a reaction of indirect hemagglutination (RNGA), a diagnostic titer of 1: 160.

With toxocariasis, a serological test is the only available method to verify the diagnosis. Use ELISA with toxocar antigens. Diagnostic is considered an antibody titer of 1: 800 and higher. With an ocular form of toxocariasis, a diagnostic titer of 1: 200 is considered. In patients without eye damage, titers of 1: 200 - 1: 400 may indicate the carriage of toxocar larvae, which was not accompanied by a clinical picture of the disease. Such results require clinical follow-up of the patient and repeated serological examination after 3 to 4 months.

In the diagnosis of echinococcosis, ELISA, RNGA, latex agglutination (RLA) reactions are usually used, less often double gel diffusion, counter immunoelectrophoresis, and the method of fluorescent antibodies. The most sensitive (90-95%) is ELISA, consider the diagnostic titers for ELISA 1: 400; RNGA - 1: 320; RLA - 1: 8.

In a number of countries, ELISA of blood and cerebrospinal fluid are used to diagnose cysticercosis.

The results of serological studies can be false positive in the presence of other invasions. If detecting antibody titers lower than diagnostic ones, it is necessary to repeat them in dynamics after 1-2 months.

The parasitological method is considered the "gold standard" for the diagnosis of helminthiases, however, due to the peculiarities of the pathogenesis of tissue helminthiases, its implementation may be difficult or even impossible.

With toxocariasis, this method is used only for the diagnosis of the ocular form of the disease in cases of surgical intervention.

For the diagnosis of trichinosis, it is effective to detect trichinella larvae by microscopic examination of meat samples (suspected infection factor) by compression trichinoscopy or by digesting meat samples in artificial gastric juice. In rare cases, to confirm the diagnosis (but not earlier than the 9-10th day of the disease), they resort to a biopsy of the patient’s muscles (trapezius, deltoid or gastrocnemius), followed by a histological examination of the biopsy.

To detect echinococcosis, microscopic examination is subject to surgical material, in which fragments of the membranes, hooks and scolexes of the parasite are found.
When cysts break into the lumen of hollow organs, helminth fragments can be detected in sputum, duodenal contents, pleural or ascitic fluids, occasionally in the feces.

With cysticercosis, obtaining biopsy material for parasitological examination is often impossible or difficult. In some cases, a lymph node biopsy is possible. Diagnosis of cysticercosis can be facilitated by the detection of patients with teniosis when teniids and mature segments of pork tapeworm are detected in the feces of sick eggs, which are separated in groups of 5-6, less often one by one, or if there is anamnestic data on such findings.

Non-specific methods of laboratory research are becoming important in the diagnosis of helminthiasis.

Liquor examination is used for clinical reasons. With lesions of the brain and its membranes with complicated forms of trichinosis, neurocysticercosis, lymphocytic pleocytosis, the predominance of eosinophils, an increased protein content are more often observed.

A hematological examination for tissue helminthiases, as a rule, reveals blood eosinophilia of varying severity. Low values ​​of blood eosinophilia are characteristic of eye damage (toxocariasis, cysticercosis), in the presence of an intact echinococcal cyst. In other cases, this indicator depends on a number of reasons: the severity of clinical manifestations, the period of the disease (exacerbation or remission), the presence of complications (rupture of an echinococcal cyst), and the immunological reactivity of the body.

With toxocariasis, along with blood eosinophilia, leukocytosis, moderately expressed normochromic anemia, can be noted.

With trichinosis, there is a direct relationship between the intensity of eosinophilia and the severity of the clinical manifestations of the disease. The clinically expressed course of invasion is accompanied by an increase in the number of eosinophils in the blood up to 5060% against the background of leukocytosis up to 10 - 30 x 10 / l. Extremely severe forms of the disease, on the contrary, occur with hypoeosinophilia, and in the terminal period with aneosinophilia. The maximum severity of eosinophilia reaches with a mild form at the 4th week of illness, with moderate and severe - at the 3rd week. The appearance of severe organ complications is accompanied by a sharp decrease in the number of eosinophils in peripheral blood. Eosinophilia up to 10-15% can persist for 2 to 3 months or more after recovery.

In some cases, especially with a complicated course of helminthiases, a moderately increased ESR can be noted.

Biochemical blood tests for tissue helminthiases of various etiologies reveal dysproteinemia (hypoalbuminemia, hypergammaglobulinemia) against the background of general hypoproteinemia (especially pronounced in alveococcosis), often an increased level of AlAT, thymol test, C-reactive protein.

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Laboratory diagnosis of tissue helminthiases

  1. Antonov M.M .. Tissue helminthiases in adults and children (epidemiology, clinic, diagnosis, treatment, prevention), 2004

  2. Immunopathogenesis of tissue helminthiases
    Helminth larvae formed after infection of a person from the intestines penetrate into the blood and are hematogenously carried to organs, where they can remain viable for many years, determining the clinical picture of the disease. In some cases, re-migration of larvae is possible. Tissue migration is associated with serious pathological changes in the human body, as specific,
  3. Treatment of tissue helminthiases
    Treatment of patients with tissue helminthiases, regardless of severity, is carried out in a hospital. In the acute period of the disease with severe forms of trichinosis, toxocariasis, cysticercosis, complicated forms of echinococcosis (rupture or suppuration of an echinococcal cyst), bed rest is prescribed. A complete diet enriched with vitamins is shown. Etiotropic therapy. It is indicated for all forms of tissue
  4. HELMINTHIASES CAUSED BY TISSUE NEMATODES
    James J. Plorde Helminthiasis caused by Angiostrongylus cantonensis Definition. Angiostrongylus cantonensis is a pulmonary helminth, the causative agent of the frequent form of eosinophilic meningitis found in Southeast Asia and the tropical countries of the Pacific. Etiology. Adult helminths - thin filarias (up to 20 mm long) - inhabit and lay their eggs in
  5. Clinical and epidemiological characteristics of certain types of tissue helminthiases
    Toxocarosis (Toxocarosis) - zoonotic geohelminthiasis caused by toxocar larvae, which occurs with damage to internal organs and eyes. Etiology. The causative agents of toxocariasis are the larvae of nematodes of the family Anisakidae of the genus Toxocara: Toxocara canis (a helminth that parasitizes in canines, which is most important in human pathology) and Toxocara mystax (helminth
  6. Tissue destruction and tissue hypoxia syndrome
    Ischemic stroke causes a violation of the integrity of neurons and glia, a violation of aerobic oxidation and energy homeostasis. Violation of the processes of aerobic oxidation in the brain is naturally accompanied by an increase in the concentration of lactate in the systemic circulation. Damage to the cell mass of the brain entails the release of the cytoplasmic and mitochondrial enzyme -
  7. LECTURE No. 15. Helminthiasis in children. Clinic, diagnosis, treatment, prevention
    Helminthiasis - a disease that develops when localized in the body of parasitic helminth worms and their larvae. Classification of helminthiases: 1) on the biological principle: nematodoses (roundworms), cestodoses (tape), trematodoses (flukes); 2) according to the epidemiological: geohelminthoses, biohelminthoses,
  8. Postmortem diagnosis of helminthiases
    Complete helminthological autopsy of animals according to K.I. Scriabin is carried out in cases where it is necessary to have a complete picture of helminth infection of all organs and tissues of animals. To do this, before opening the corpse carefully examine its skin and mucous membranes for the presence of helminths. According to the rules of conventional sectional technique, all organs are separated from the corpse without breaking their connection with each other.
  9. The most common causative agents of helminthiases. Methods for their diagnosis and rational timing of animal studies
    Many methods of coproovoscopic diagnosis of helminthiases are known. Many of them are described in practical guidelines published in various publications (see Recommended reading). The proposed manual provides the most informative of them, tested in practice. The time of epizootic manifestation and the so-called peak of one or another helminthiasis in different geographical areas does not
  10. Cherepanov A.A., Moskvin A.S., Kotelnikov G.A., Khrenov V.M. Differential diagnosis of helminthiases by the morphological structure of eggs and larvae of pathogens, 1998

  11. LABORATORY DIAGNOSTIC METHODS
    The clinical picture of fungal skin diseases is very polymorphic, therefore, in all cases, the diagnosis must be confirmed by laboratory research methods. For laboratory diagnosis of mycoses, microscopic, luminescent, cultural, immunological (allergological and serological) research methods are used, as well as animal experiments. Laboratory diagnostics
  12. Laboratory instrumental diagnostics
    Diagnosis of severe chronic heart failure with clearly defined clinical manifestations usually does not present great difficulties. It is based mainly on the following clinical criteria for cardiac decompensation, shown in table 50. In most cases, the diagnosis of chronic heart failure requires two "large" criteria or one "large" and two "small" criteria. IN
  13. Laboratory diagnosis of syphilis
    To establish the diagnosis of syphilis, a necessary condition is laboratory confirmation, including the detection of the pathogen and serological reactions. For bacteriological research, tissue fluid (serum) is taken on pale treponema, which is obtained by the method of irritation of erosion or ulcers in the primary period, weeping and erosive papules, erosion of the mucous membranes in the secondary
  14. Laboratory diagnostics
    Among laboratory methods for diagnosing IE, the bacteriological study of venous and arterial blood, conducted at least 3 times, is of leading importance. The determination of the microbiological nature of IE in each case is necessary for the selection of ABT. This is especially important in the development of fungal and mixed infections. Depending on the technique used, the frequency of inoculation of the pathogen IE
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