Bahman Maleki
1* 
, Hadi Khatounaki
2, Nahid Haghshenas
3, Reza M Robati
1, Mostafa Rezaei-Tavirani
4, Mahmoodreza Behravan
5, Ahmad Abolghazie
61 Skin Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
2 Independent Researcher, MSc in Parasitology, Shiraz, Iran
3 Remote Sensing & GIS, Tarbiat Modares University, Tehran, Iran
4 Proteomics Research Center, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
5 Infectious Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran
6 Department of Medical Parasitology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
Abstract
Human toxocariasis (HT), caused by the larvae of Toxocara canis and Toxocara cati, is a globally prevalent parasitic disease with significant public health implications. Although soil is a primary route for the transmission of Toxocara spp., data on soil contamination in Iran remain limited. To address this gap, the present study expands upon a systematic review published in 2018, which analyzed studies conducted between January 2000 and November 2016. Using recent data to guide control strategies, the study provides an updated estimate of the prevalence of Toxocara spp. eggs in the soil of public areas in Iran. Accordingly, a comprehensive literature review was performed in accordance with PRISMA guidelines, covering studies published between January 2000 and April 2025. A random-effects meta-analysis was performed to pool prevalence rates. In addition, associations with geographic and environmental factors were examined through meta-regression and sensitivity analyses. Overall, 28 studies (31 datasets) were included, comprising 6,264 soil samples collected from 25 provinces of Iran. The pooled prevalence of Toxocara spp. eggs was 16% (95% confidence interval: 12–21%), with high heterogeneity (I²= 94.4%, P< 0.001). This high heterogeneity across studies may be attributed to differences in sampling methods, climatic conditions, study quality, and regional variations in stray animal density. The prevalence of this species varied by region and climate, with the highest rates reported in the central region (23%) and in hot desert climates (20%). The sample size, year of publication, or environmental variables had no statistically significant effects. These findings underscore significant environmental contamination by Toxocara spp. eggs throughout Iran. Further, this contamination indicates an ongoing risk of human infection. In general, the results highlight the need for geographically targeted interventions, public education, and integrated One Health strategies to inform health policies and prevent HT.