Objective To understand the infection status and the main risk factors of soil-transmitted nematodes in children in the poverty-stricken areas of Guizhou Province and Sichuan Province,so as to provide the evidences for making suitable control strategies in these areas. Methods A total of 95 villages and 6 primary schools in 6 poor counties in the two provinces were select-ed as investigation sites according to the stratified random sampling method. Eleven preschool children aged 3-5 years in each sam-ple village and 11 school children aged 8-10 years in each sample school were chose as investigation objectives,their feces were collected and examined by Kato-Katz technique. In addition,the village doctor and cadres in each village were investigated by a standardized questionnaire to understand the deworming condition of children and the social economy and sanitary status in 2009. Then the correlation between average soil-transmitted nematode infection rate and its influencing factors was analyzed by the Tobit model. Results A total of 1 707 children from 95 villages in the two provinces were examined. In Guizhou Province,the total in-fection rate of soil-transmitted nematodes in children was 46.1%,and the infection rates of Ascaris lumbricoides,Hookworm,and Trichuris trichiura were 31.1%,4.1% and 10.8% respectively,and the corresponding rates in Sichuan Provinces were 9.8%, 3.6%,3.5%,2.7%,respectively. In the dimension of school,a total of 890 school-aged kids from 46 schools in the two provinces were examined,the infection rates of soil-transmitted nematodes,Ascaris lumbricoides,Hookworm,and Trichuris trichiura in Guizhou Province were 53.8%,32.7%,6.6% and 14.4%,respectively,and the corresponding rates in Sichuan Province were 7.3%,2.2%,2.9% and 2.2%,respectively. The results from Tobit analysis indicated that the proportion of children accepted deworming treatment and the paddy field in the cultivated area were statistically correlated to the infections of soil-transmitted nematodes and Ascaris lumbricoides(all P < 0.05). Conclusions The soil-transmitted nematode infection rates of children are still at a high level in poor areas of southwest China. In order to decrease the infection rates,besides the long-term deworming, water supply and sanitary improvement,and the health education should be strengthened,and the treatment of soil-transmitted nematodes should be covered by the New Rural Cooperative Medical System.

Objective: To investigate the development status and risk factors of infants and toddlers in rural China. Methods: In this cohort study, 603 infants (6-12 months of age, Phase Ⅰ) in the rural areas of QinLing-Bashan (Qin-Ba) in Shaanxi were recruited in the control group that received no intervention from April 2013 to October 2015. Three follow-up visits were performed every six months (Phase Ⅱ(12-18 months of age), Phase Ⅲ (18-24 months of age) and Phase Ⅳ(24-30 months of age)). In all the 4 phases (Ⅰ-Ⅳ), general data of the children and the families were collected by questionnaires, early childhood growth and development were assessed by door to door visits, children's hemoglobin levels were determined by laboratory tests, and the cognitive and motor development screening was conducted by the Bayley Scales of Infant and Toddler Development. Logistic regression was used to analyze the risk factors affecting the development of infants and toddlers in rural areas and the data were analyzed in terms of risk factors from infants, guardians and family. Results: Phase Ⅱ, Phase Ⅲ and Phase Ⅳ survey recruited 497, 483 and 486 participants respectively. The incidences of cognitive impairment (mental development scores<80) in rural areas of southern Shaanxi were 13.4% (81/603) in Phase Ⅰ(6-12 months), 20.1%(100/497) in PhaseⅡ(12-18 months), 42.9% (207/483) in Phase Ⅲ(18-24 months) and 50.4%(245/486) in Phase Ⅳ(24-30 months) respectively, which showed a significant increase with age (χ²=233.40, P<0.01); the incidences of psychomotor impairment (psychomotor development scores<80) of Phase Ⅰ, Phase Ⅱ, Phase Ⅲ and Phase Ⅳ were 25.0% (151/603), 26.8% (133/497), 8.3% (40/483) and 11.9% (58/486), which showed a significant decrease with age (χ²=87.08, P<0.01). Multivariate logistic regression analysis showed that the leading risk factor of the cognitive development of 24-30-month-old children was the mothers' poor education background (≤9 years of school education) (OR=2.56, P<0.01), and the main risk factors affecting psychomotor development were the mothers' poor education background (≤9 years of school education) (OR=2.64, P<0.05) and growth retardation (OR=2.95, P=0.07). Conclusions The early childhood development (especially cognitive development) in the rural areas of Qin-Ba in Shaanxi of China is not optimistic. More attention should be paid to the early childhood development in rural China, especially to the development of children from the mothers with poor education background.