Soil-Transmitted Helminth Prevalence and Infection Intensity Among Geographically and Economically Distinct Shuar Communities in the Ecuadorian Amazon

Abstract

Soil-transmitted helminth (STH) infections can result in a variety of negative health outcomes (e.g., diarrhea, nutritional deficiencies). Market integration (MI; participation in market-based economies) has been suggested to alter levels of STH exposure due to associated changes in diet, sanitation, and behavior, but the effects are complicated and not well understood. Some effects of economic development result in decreased exposure to certain pathogens, and other factors can lead to higher pathogen exposure. With geographic location used as a proxy, the present study investigates the effects of economic development on parasite load among an indigenous population at multiple points along the spectrum of MI. This research has many implications for public health, including an increased understanding of how social and economic changes alter disease risk around the world and how changing parasite load affects other health outcomes (i.e., allergy, autoimmunity). Specifically, this study examines the prevalence of intestinal helminths among the Shuar, an indigenous group in the Morona-Santiago region of Ecuador, from 2 geographically/economically separated areas, with the following objectives: (1) report STH infection prevalence and intensity among Shuar; (2) explore STH infection prevalence and intensity as it relates to age distribution in the Shuar population; (3) compare STH infection patterns in geographically and economically separated Shuar communities at different levels of MI. Kato-Katz thick smears were made from fresh stool samples and examined to determine STH presence/intensity. Results indicate that 65% of the 211 participants were infected with at least 1 STH. Twenty-five percent of the sample had coinfections with at least 2 species of helminth. Infection was more common among juveniles (<15 yr) than adults. Infection prevalence and intensity was highest among more isolated communities with less market access. This study documents preliminary associations between STH infection and exposure to MI, with implications for public health research and interventions.

Desigualdad en la prevalencia de parasitosis intestinal en escolares de una escuela urbana y dos rurales de la comuna de Puerto Montt

“…Las prevalencias encontradas en este estudio en el sector rural se acercan a otros estudios realizados en Chile en territorios similares 9,11,12 y en América Latina y el Caribe (ALC) [27][28][29] , diferenciándose de otros que declaran prevalencias sobre 90% 30 , donde incide la condición étnica además de pobreza e insalubridad. En el sector urbano, la prevalencia encontrada en este estudio es más baja que en el sector rural y menor que la reportada por Araya et al , no encontrándose otros estudios en sectores urbanos con los que comparar, por lo menos en esta última década.…”

Novel approaches to the diagnosis of Strongyloides stercoralis infection

“…Until now, faecal surveys on the prevalence of STHs have often relied on stool concentration methods such as the Kato-Katz [ [15][16][17][18], Mini-FLOTAC and McMaster [19] techniques. With standard methods, prevalence studies are affected by a lack of sensitivity.…”

Immune function in Amazonian horticulturalists

“…Extremely high levels of IgE, indicative of parasite infections, have been documented in indigenous groups in Venezuela, Ecuador, and Bolivia (Blackwell et al, 2010; Martin et al, 2013). High prevalences of helminth infection, particularly Ascaris lumbricoides , have been documented in the Shuar of Ecuador, Yanomamo of Brazil, and many other Amazonian populations (Salzano and Callegari-Jacques, 1988; Hurtado et al, 2008; Cepon-Robins et al, 2014). Tuberculosis is prevalent and a source of morbidity and mortality in many indigenous South American populations (Hill and Hurtado, 1996; Hurtado et al, 2004).…”