Abstract: Objective · To investigate the seroprevalence of Toxocara canis (T. canis) preschool children in Yangpu District of Shanghai, and to evaluate the environmental contamination with T. canis eggs in public areas. Methods · A cross-sectional study was performed. A total of 789 children 7 kindergartens in Yangpu District of Shanghai were asked to fill up a questionnaire. Serum samples of 605 children were testedusing an enzyme linked immunosorbent assay for the detection of specific IgG antibody against T. canis. Sixty-seven soil samples and 69 fecal samples of dogs were collected the neighborhood close to the kindergartens. DNAs were then extracted all samples and amplifiedPCR targeting T. canis ribosomal internal transcribed spacer 2 (ITS-2) gene fragments. Results · 1.0% of the serum samples were positive for IgG against T. canis. The positive rates of T. canis DNA in the soil and feces were 4.5% and 27.5%, respectively. More than 90.0% of the children had good habits of hand washing and their parents were aware of dog-related diseases and prevention. 6.8% of the children kept dogs at home and 77.8% of the dogs received anthelmintic treatment. 83.5% of the children reported stray dogs in the neighborhood but only 2.0% had regular contact with stray dogs. Conclusion · Seroprevalence of T. canis specific IgG was low among preschool children in this area. Good hygienic habits and prevention consciousness may be the main reasons for this result. But the high environmental contamination of T. canis eggs makes it necessary to preventive public health measures which will play an important role in the prevention and treatment of ocular toxocariasis.

Key words: Toxocara canis, ocular toxocariasis, seroepidemiology, preschool children, environment