Seroprevalence and Associated Risk Factors of Toxocariasis in Children With Hypereosinophilia in Iran.

INTRODUCTION: Toxocariasis is a significant parasitic disease with a global distribution, caused by two nematodes Toxocara canis (a parasite of the dog's small intestine) and Toxocara cati (a parasite of the cat's small intestine). Eosinophilia, characterized by an elevation in peripheral blood eosinophil counts exceeding 10%, serves as a significant clinical marker for helminthic infections. This study aims to investigate the seroepidemiology of T. canis and its risk factors in children with hypereosinophilia in Lorestan Province, Western Iran. MATERIALS & METHODS: This cross-sectional study was conducted from May 2021 to June 2023, involving a cohort of 300 children aged 2 to 15 years who presented with eosinophilia (>10%) and were referred to healthcare facilities in Lorestan Province. Children who were younger than 12 years (between 2-12 years), had blood eosinophil counts exceeding 10%, and consented to participate in this study were deemed to fulfill the inclusion criteria. The prevalence of toxocariasis was confirmed serologically by detecting human IgG antibodies utilizing commercially available anti-IgG-Toxocara canis kits. Demographic and some risk factors regarding the enrolled subjects, including gender, age, type of residence, consuming unwashed vegetables and fruits, and history of animal contact, were collected. RESULTS: Out of a total of 300 children with eosinophilia, 35(11.7%) were identified as seropositive for toxocariasis. Specifically, female participants were less likely to contract toxocariasis than male children [P=0.002, OR=0.184 (0.052-0543)]. Additionally, individuals living in urban environments exhibit a 4.54-fold increased likelihood of contracting toxocariasis compared to their rural counterparts [P=0.010, OR=4.546 (1.433-9.419)]. Furthermore, individuals who did not consume unwashed vegetables demonstrated a reduced risk of toxocariasis infection [P=0.001, OR=0.016 (0.005-0.048)]. CONCLUSION: The findings of our study indicated a significant seroprevalence of toxocariasis among children exhibiting eosinophilia in western Iran. This suggests that toxocariasis should be regarded as a potential etiological factor for eosinophilia, particularly in individuals with a history of consuming unwashed fruits and vegetables, as well as those residing in rural regions of Iran.