The relationship between Toxocara infection and epilepsy was previously demonstrated by several case-control studies and case reports. These previous studies were often based on the enzyme-linked immunosorbent assay (ELISA) using Toxocara excretory-secretory antigens, which are not specific due to cross-reactivity with other parasitic infections such as ascariasis, trichuriasis, and anisakiasis. An immunoblot analysis is highly specific and can detect low levels of Toxocara antibodies. Therefore, this assay may be useful in the identification of toxocariasis in epileptic patients. We examined patients who had epilepsy and healthy subjects for seropositivity for Toxocara infection by ELISA and Western blotting. Out of 85 epileptic patients, 10 (11.8%) and 3 (3.5%) persons exhibited Toxocara immunoglobulin G (IgG) antibodies responses by ELISA and by both techniques, respectively. Moreover, in the healthy group ( ), 3 (3.5%) persons were positive by ELISA, but none was detected by Western blotting. This study indicates that Toxocara infection is a risk factor for epilepsy in Iran. These findings strongly suggest the need to perform Western blotting immunodiagnosis, as well as the ELISA using Toxocara excretory-secretory antigens, to improve diagnosis of human toxocariasis in patients with epilepsy. 1. Introduction Human toxocariasis is a zoonotic parasitic disease caused by migration of the nematode worms Toxocara canis (dog) or Toxocara cati (cat) larvae to the organs and tissues of animals and birds. Human infection occurs when Toxocara eggs containing infective larvae are accidentally ingested or through consumption of raw or undercooked meat and giblets [1]. The larvae hatch in small intestine and migration through somatic organs, preferably the liver, brain, and eyes, and cause at least three syndromes: visceral larva migrans (VLM), ocular larva migrans (OLM), and covert toxocariasis [2]. The tests are available for the immunodiagnosis including enzyme-linked immunosorbent assay (ELISA) and Western blotting, both using Toxocara canis excretory-secretory (TES) antigens [3]. ELISA using TES antigens was the first method to be employed, irrespective of the clinical form of toxocariasis [4–6]. However, Magnaval et al. (1991) reported the high sensitivity and specificity of WB for immunodiagnosis of toxocariasis [7]. In addition, previous reports using both techniques indicated that Western blotting is a better method than ELISA to investigate patients suffering from visceral larva migrans or ocular larva migrans [8]. The epidemiological studies have
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