Epidemiological Study of Toxocara Eggs in the Soil of Public Parks in Iran with an Emphasis on Climatic and Seasonal Diversity

Abstract

Background: Toxocariasis is a globally important zoonotic infection acquired through contact with soil contaminated by Toxocara eggs. Despite its relevance, comprehensive data on environmental contamination across Iran’s climatic zones are lacking. We assessed the presence of Toxocara eggs in public park soils with emphasis on climatic and seasonal variation.

Methods: A cross-sectional survey was conducted from summer 2024 to spring 2025 in three climatic zones of Iran (Mountain, humid, and hot–dry). A total of 1,445 soil samples were randomly collected from a depth of 4–5 cm. Samples were examined using sucrose flotation and direct smear techniques. Microscopic identification of eggs was performed at 400× magnification.

Results: Toxocara eggs were detected in all regions studied. The humid zone showed the highest contamination rate, reaching 51% in summer. In the mountain zone, prevalence peaked in spring (44%) and was lowest in winter (12%). In the hot–dry zone, the highest contamination occurred in autumn (32%) and the lowest in summer (14%). These differences indicate the influence of climatic and seasonal conditions on egg survival.

Conclusion: The widespread detection of Toxocara eggs in public park soils highlights a considerable risk for human exposure, particularly among children. Improved environmental hygiene, responsible pet management, and public education are required. Future studies should incorporate molecular confirmation and longitudinal monitoring within a One Health framework to support targeted interventions.