A Comparative Seroprevalence Study of Toxocariasis in Hypereosinophilic and Apparently Healthy Individuals

Background: Parasitic invasion of tissues can elicit hypereosinophilia. Among helminthic infections, moderate to severe eosinophilia can be seen in toxocariasis as a pathophysiological response to a worm infection. Objectives: The current study aimed to compare the rate of toxocariasis in normal and hypereosinophilic individuals in Shiraz, southern Iran. Patients and Methods: Serum samples of 100 patients with hypereosinophilia (>10%) and 100 normal individuals (without eosinophilia) were collected. Demographic information of the participants was recorded in a predesigned questionnaire during sample collection. Anti-Toxocara antibodies in the subjects' serum were evaluated by an ELISA. Results: In the hypereosinophilic patients, 54 (54%) were male, and 46 (46%) were female, while in the normal individuals, 58 cases (58%) were male, and 42 (42%) were female. The differences in gender and age of the participants were insignificant (P = 0.46 and 0.59 respectively). Range of eosinophilia found in the patients was between 10-77%. Anti-Toxocara antibodies were detected in the serum of 2 (2%) of the hypereosinophilic patients and 3 (3%) of the normal individuals. No significant correlation was found between hypereosinophilia and the presence of anti-Toxocara antibodies in this study (P = 0.65). Conclusions: Hypereosinophilia may be due to a variety of reasons and toxocariasis is just one of these. Appropriate tests should be carried out on patients in order to rule out a Toxocara infection in hypereosinophilic individuals.