Study of Toxocara seroprevalence among patients with allergy and healthy individuals in Bulgaria

Data in the literature addressing the ability of Toxocara infection in humans to induce development of atopic disease are controversial. The aim of our study was to determine the seroprevalence of anti‐Toxocara antibodies in three groups of people: subjects with allergic symptoms and presence of allergen‐specific IgE, subjects with allergic symptoms and absence of allergen‐specific IgE, and clinically healthy blood donors. Serum samples from all subjects were tested by ELISA and Western blot for presence of specific antibodies against Toxocara canis. The results of our study did not support the link between toxocariasis and allergic manifestations in atopic patients. Among subjects with allergic symptoms and absence of atopy was found seroprevalence of 2·2% in Western blot. Same index in patients with atopy was 0·8%, and in clinically healthy blood donors 4·0%. Our study gives us grounds to consider that it is appropriate persons with allergic reactions, without evidence of atopy to be tested for presence of anti‐Toxocara antibodies in the course of their diagnostic evaluation. Data from clinically healthy persons suggest that there is a ‘hidden’ infection among the population, which is not clinically manifested.