Assessment of the diagnostic value of specific anti-Toxocara IgA in Slovakian patients suspected to have toxocarosis.

Human toxocarosis is one of the most widespread and prevalent helminthic zoonosis in many countries, including Slovakia. The aim was to evaluate the usefulness of IgA anti-Toxocara antibody detection in the serodiagnosis of toxocarosis. The levels of specific IgA antibodies were determined by excretory-secretory (ES)-enzyme-linked immunosorbent assay (ELISA). The IgA seropositivity in IgG anti-Toxocara seropositive patients (n = 52) was 32.7% and found to be highest in the oldest age groups (P = 0.026). The presence of IgA in suspected patients for toxocarosis were evaluated in respect to some characteristics of examined persons. Substantially higher IgA seropositivity was detected in patients with increased total IgE (44.8%) than in subjects with a normal level of IgE (17.4%; P = 0.036). No associations (P > 0.05) were found between IgA seropositivity and sex, level of specific IgG antibodies, avidity of IgG, eosinophilia, domicile, geophagia, traveling abroad, dog/cat ownership, or clinical symptoms. The IgA-ELISA showed sensitivity of 57.1% and specificity of 100%. Mild correlations (r = 0.302, r = 0.305, r = - 0.409) were observed between the levels of anti-Toxocara IgA antibodies and age, the amounts of eosinophils and IgA antibody levels, the amounts of eosinophils, and the values of IgG avidity, respectively. The presence of anti-Toxocara IgA may facilitate the diagnosis of toxocarosis and may well be useful for the determination of acute Toxocara infection. Moreover, this test should be accompanied by other immunological markers of examined patients (e.g., increased total IgE, eosinophilia, and low-avidity IgG antibodies).

Comparative assessment of enzyme-linked immunosorbent assay and Western blot for the diagnosis of toxocariasis in patients with skin disorders.

Background The link between various chronic skin disorders and toxocariasis was previously demonstrated by case reports and several case-control studies. However, these previous studies were based only on the Toxocara canis excretory-secretory-enzyme-linked immunosorbent assay (TES-ELISA) serological technique, which is not specific due to cross-reactivity with parasites of the genera Anisakis or Ascaris. Immunoblot analysis is highly specific and can detect very low levels of Toxocara antibodies. Therefore, this technique may be useful in the identification of Toxocara infection in patients with chronic skin disorders. Objectives Because urticaria and pruritus/prurigo are skin conditions previously associated with toxocariasis, we carried out a prospective study using both TES-ELISA and Toxocara Western blot on 113 patients with either chronic urticaria (n = 84) or chronic pruritus (n = 29). Methods Patients were matched with controls according to gender, age and residence location (rural or urban area). Data were analysed using a Mantel-Haenszel chi(2) test. Results The proportion of positive TES-ELISA results was not significantly different for patients with chronic skin disorders (urticaria or pruritus/prurigo) from that of control subjects. However, the proportion of positive immunoblot results was significantly higher for patients with chronic urticaria than for control subjects (P = 0.009). Conclusions Our study demonstrates the need to perform Western blotting immunodiagnosis, whatever the TES-ELISA result, to improve diagnosis of human toxocariasis in patients with chronic urticaria caused by Toxocara infection.