Антитела к бруцеллам (Brucella, IgА)

Brucella, IgA antibody testing supports the laboratory assessment of brucellosis across the clinical spectrum, including active and chronic infection. The assay identifies IgA-class antibodies directed against Brucella antigens by ELISA, aiding interpretation when symptoms or exposure history are consistent with brucellosis. This test is considered in symptomatic individuals, in population-based epidemiologic evaluations, and during screening of candidates for brucellosis vaccination where such programs are implemented. It is also used when genitourinary or joint involvement occurs in the setting of exposure risks such as consumption of unpasteurized goat milk or occupational contact with livestock.

Brucellosis is a zoonotic infection with multisystem involvement and a tendency to become chronic; heightened allergic reactivity contributes to its pathogenesis. Transmission occurs most often through ingestion of contaminated food or water, classically unpasteurized milk and meat from infected animals; airborne and contact routes may occur among those who handle livestock or animal products. Major animal reservoirs include goats, sheep, cattle, and swine, with less frequent transmission from horses, camels, and other species. Infected animals shed organisms in feces, urine, milk, and amniotic fluid. Brucella can persist in the environment—over two months in water, approximately three months in raw meat (about 30 days if salted), around two months in brined cheese, and up to four months in animal wool. Heat inactivates the organism: boiling is lethal, and exposure to 60 °C for 30 minutes is sufficient to kill it. Vertical transmission may occur during pregnancy, and postnatal transmission is possible via breastfeeding. Humans are highly susceptible; postinfection immunity persists for approximately 6–9 months, and reinfection is reported in 2–7% of cases. The incubation period averages 1–4 weeks but may extend to 2–3 months with latent carriage. Acute disease often begins abruptly, though in older adults onset may be gradual with prodromal malaise, insomnia, fatigue, arthralgia, and myalgia, followed by fever with alternating chills and sweating and a generally moderate intoxication syndrome despite high temperatures. Chronic brucellosis follows a relapsing–remitting course with multi-organ manifestations; fever and systemic toxicity are usually modest, with temperatures commonly remaining subfebrile. Exacerbations may recur at 1–2 month intervals, and formation of new infectious foci within the body worsens overall status. Clinical features depend on the predominant organ system involved and the intensity of the allergic component. Diagnosis is established by detection of the organism in blood, lymph node aspirate, or cerebrospinal fluid, and by serologic testing. A positive result in at least 3–4 different serologic assays is considered sufficient for diagnosis. The brucellin skin test (Bürne) typically becomes positive from days 20–25 of illness and may remain reactive for several years after recovery. ELISA assists in distinguishing acute from chronic forms and is useful for identifying antibodies in serum and plasma; measuring specific immunoglobulin classes helps determine the presence of infection and gauge disease severity.