Abstract: 【Abstract】   Objective   To investigate the intelligence level and characteristics of cognitive structure of school-age children infected with soil-transmitted helminthes （STH）（hookworm, Ascaris lumbricoides and Trichuris trichiura）.   Methods  1 031 children of 9 to 12 years old from Baishui village of Guangxi, Longzhou and Xinzhu villages of Hainan were selected for the survey. Stool samples from children were collected and examined by modified Kato-Katz method. 77 children infected with only one species （hookworm,  A. lumbricoides, or T. trichiura） were used as case group and 39 healthy children as control. The cognitive ability for children were assessed by WISC-Ⅳ.   Results   A total of 378 cases with STH infection was found from 1 031 children, and the overall prevalence of STH infection was 36.7%. The prevalence of moderate and heavy STH infections was 16.8% （173/1 031）. The verbal comprehension （VCI）, working memory （WMI）, processing speed （PSI） and full scale IQ （FSIQ） indices of case group were lower than those of control group （P＜0.05）. The VCI （97.2）, WMI （84.6）, PSI （91.1） and FSIQ （95.4） indices in moderate/heavy infection group were lower than those in light infection group （99.2，103.3，88.3 and 99.1, respectively） and control group （102.0，104.2，91.9 and 100.1,  respectively）（P＜0.05）. The WMI index in hookworm infection group （83.7） was lower than that in A. lum-bricoides （87.6） or T. trichiura （88.3） infection groups （P＜0.05）. The PSI index of T. trichiura infection group （92.8） was lower than that of A. lumbricoides （97.3） or hookworm （94.4） infection groups （P＜0.05）.   Conclusion   The total intelligence level of STH infection children is in a normal range, or on borderline. The low VCI, WMI, PSI indices have been found in moderate/heavy STH infection children.

Key words:  , Soil-transmitted helminth；School-age children；Case control；Cognitive function