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.