Soil-transmitted helminth infections and nutritional status in Ecuador: findings from a national survey and implications for control strategies

Objective The estimation of prevalence and intensity of soil-transmitted helminth (STH) infections at a country-level is an essential prerequisite for the implementation of a rational control programme. The aim of this present study was to estimate the prevalence and distribution of STH infections and malnutrition in school-age children in rural areas of Ecuador. Design Cross-sectional study from October 2011 to May 2012. Setting Eighteen rural schools were randomly selected from the three ecological regions of Ecuador (coastal, highlands and Amazon basin). Participants 920 children aged 6-16 years. Main outcome measures Prevalence and intensity of STH infections associated with malnutrition (thinness/wasting or stunting). Results The results showed that 257 (27.9%) children were infected with at least one STH parasite. The prevalence of Trichuris trichiura, Ascaris lumbricoides and hookworm was 19.3%, 18.5% and 5.0%, respectively. Malnutrition was present in 14.2% of children and most common was stunting (12.3%). Compared with other regions, schoolchildren in the Amazon region had the highest STH prevalence (58.9%) of which a greater proportion of infections were moderate/heavy intensity (45.6%) and had the highest prevalence of malnutrition (20.4%). A positive association was observed between moderate to heavy infections with A. lumbricoides and malnutrition (adjusted OR 1.85, 95% CI 1.04 to 3.31, p=0.037). Conclusions Our estimate of the prevalence of STH infections of 27.9% at a national level in Ecuador is lower than suggested by previous studies. Our data indicate that schoolchildren living in the Amazon region have a greater risk of STH infection and stunting compared with children from other regions. The implementation of school-based preventive chemotherapy and nutritional supplement programmes within the Amazon region should be prioritised. Long-term control strategies require improvements in water, sanitation and hygiene.