Soil-Transmitted Helminth Infections and Correlated Risk Factors in Preschool and School-Aged Children in Rural Southwest China

Abstract

We conducted a survey of 1707 children in 141 impoverished rural areas of Guizhou and Sichuan Provinces in Southwest China. Kato-Katz smear testing of stool samples elucidated the prevalence of ascariasis, trichuriasis and hookworm infections in pre-school and school aged children. Demographic, hygiene, household and anthropometric data were collected to better understand risks for infection in this population. 21.2 percent of pre-school children and 22.9 percent of school aged children were infected with at least one of the three types of STH. In Guizhou, 33.9 percent of pre-school children were infected, as were 40.1 percent of school aged children. In Sichuan, these numbers were 9.7 percent and 6.6 percent, respectively. Number of siblings, maternal education, consumption of uncooked meat, consumption of unboiled water, and livestock ownership all correlated significantly with STH infection. Through decomposition analysis, we determined that these correlates made up 26.7 percent of the difference in STH infection between the two provinces. Multivariate analysis showed that STH infection is associated with significantly lower weight-for-age and height-for-age z-scores; moreover, older children infected with STHs lag further behind on the international growth scales than younger children.

Effect of Deworming on Indices of Health, Cognition, and Education Among Schoolchildren in Rural China: A Cluster-Randomized Controlled Trial

“…The pattern of rapid reinfection after antihelminthic treatment (in our case, we tested the follow-up fecal samples 6 months after treatment) has been consistently identified in geographically diverse populations in both children and adults, 46 and was previously confirmed in our study area. 8,25 In our scenario, we surmise that children in the intervention group were cleared of STH infection after each of the two rounds of antihelminthic treatment, but experienced high rates of reinfection within the subsequent months leading up to postintervention evaluation. In a 2012 article by Jia and others, helminth reinfections occur rapidly after treatment, particularly for A. lumbricoides and T. trichiura.…”

“…Multivariate analyses of binary outcome measures-STH prevalence, anemia prevalence, and school attendance-were performed using STATA's logistic regression model, also taking into account paired fixed effects and clustering at the township level. Following previous studies, 8,25,43 we adjusted for the following two sets of additional covariates at baseline survey in the multivariate analyses to increase statistical precision: student individual characteristics (gender; age; boarding status; belonging to the Dong, Miao, or Shui minority groups) and household characteristics (number of siblings, number of durable assets, parental migration status, educational attainment of parents). We also included pair fixed effects at the township level.…”

“…25,26 For example, more than 40% of school-aged children in rural areas of Guizhou Province in southwest China are infected with STH. 8,25 The primary aim of this RCT is to examine the impact of a deworming intervention on STH infection prevalence, infection intensity, nutritional indicators, cognitive abilities, and school performance among school-aged children in rural Guizhou Province. In doing so, we also assess treatment compliance among children who were randomized to receive the intervention and offered treatment by public health officials.…”

Malaria and soil-transmitted intestinal helminth co-infection and its effect on anemia: a meta-analysis

“…43 Published studies have documented that obtaining only a single fecal sample for A. lumbricoides and T. trichiuria can lead to underestimation of infection rates by up to 50%. 54,74 Sensitivity for low infection rates increased from 20 to 54% when three fecal samples were examined on separate days. 74,75 Although confounding factors were addressed in many of the primary studies identified for the current analysis, it is likely that there still may be unmeasured confounding factors which might have induced bias to this meta-analysis.…”

“…54,74 Sensitivity for low infection rates increased from 20 to 54% when three fecal samples were examined on separate days. 74,75 Although confounding factors were addressed in many of the primary studies identified for the current analysis, it is likely that there still may be unmeasured confounding factors which might have induced bias to this meta-analysis. There could have been a temporal mismatch between the data, which came from several different time points, ranging from 2003 to 2013.…”