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Trichinosis - Diagnosis
Last reviewed: 23.04.2024
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During outbreaks and group diseases in the presence of typical symptoms in patients, diagnosis of trichinosis does not cause difficulties.
It is necessary to establish a common source of infection and, if possible, to conduct a study of food residues (meat or meat products) for the presence of Trichinella larvae. Difficulties arise in the diagnosis of sporadic cases of trichinosis. In such situations, a significant epidemiological history.
In the absence of data on the source of infection, sometimes muscle biopsy (deltoid or gastrocnemius in bedridden patients or long back muscles in walking patients) is sometimes used: a piece of muscle tissue weighing 1 g is examined under a microscope at a small magnification for the presence of Trichinella larvae.
Serological diagnosis of trichinosis is used only at week 3 of the disease, since in the first 2 weeks local immunity reactions predominate (intestinal invasion phase), and the concentration of specific antibodies in the blood is low. Use ELISA with antigen T. Spiralis and RNGA. The timing of the appearance of diagnostic antibody titers depends on the intensity of the invasion and the type of pathogen: in patients with trichinosis, who became infected with the use of pig meat heavily invaded by trichinella, antibodies are detected on the 15-20th day after infection; if the intensity of the invasion is less, the timing of the detection of antibodies is prolonged. When meat is infected with wild animals (T. S. Nativa), the initial detection of antibodies can be up to 1.5 months. Titres of specific antibodies can increase within 2-4 months after infection, significantly decreasing after 4-5 months, but can remain at the diagnostic level to 1.5 years, and with intensive infection - up to 2-5 years. Early serological diagnosis of trichinosis requires simultaneous setting of two serological reactions: ELISA and RNGA. The sensitivity in these cases reaches 90-100% and the specificity is 70-80%. People who consumed meat contaminated with trichinella carry out a serological examination 2-3 weeks after preventive treatment. Diagnostic indicators of serological reactions - confirmation that these individuals had had trichinosis.
In all patients with trichinosis, along with clinical analyzes of blood and urine, a biochemical blood test, ECG, X-ray examination of the lungs, determine the level of electrolytes in the blood plasma.
Differential diagnosis of trichinosis
Differential diagnosis of trichinosis is carried out with acute intestinal infections, typhoid and paratyphoid fever, acute respiratory disease, typhus, measles, leptospirosis, yersiniosis, Quincke edema. With the growth of eosinophilia in the blood, trichinosis is differentiated from the acute phase of other helminthiases (opisthorchiasis, fascioliasis, strongyloidiasis, toxocarosis), eosinophilic leukemia, nodular periarteritis, dermatomyositis.
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