目的·调查上海市杨浦区学龄前儿童犬弓首蛔虫的血清阳性率以及犬弓首蛔虫在公共环境中的存在情况。方法·采用横断面研究设计，对上海市杨浦区7家幼儿园的789名大班儿童进行了犬弓首蛔虫感染相关的问卷调查，用酶联免疫吸附法检测其中605名儿童血清中犬弓首蛔虫特异性IgG抗体的阳性率。并在这些幼儿园附近的小区和公园共采集67份土壤样品和69份犬粪便样品，提取基因组DNA，用PCR扩增法检测犬弓首蛔虫核糖体DNA第2内转录间隔区（internal transcribed spacer 2，ITS-2）序列基因。结果·上海市杨浦区儿童犬弓首蛔虫特异性抗体的血清阳性率为1.0%。土壤和犬粪便样品的犬弓首蛔虫DNA阳性率分别为4.5%和27.5%。问卷调查显示90.0%以上的儿童洗手习惯好、家长预防意识强；6.8%的儿童家中有狗，77.8%的狗接受过驱虫治疗；83.5%的儿童家附近有流浪狗，但仅2.0%的儿童接触过流浪狗。结论·该地区学龄前儿童犬弓首蛔虫特异性抗体的血清阳性率较低，好的卫生习惯与预防意识可能是主要原因。但环境中仍存在较高的犬弓首蛔虫感染风险，因此推广实施预防性的公共卫生措施对我国学龄前儿童眼弓蛔虫病的早期防治有重大意义。

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.