Regional variation in Ascaris lumbricoides and Trichuris trichiura infections by age cohort and sex: effects of market integration among the indigenous Shuar of Amazonian Ecuador.

Theresa E Gildner,Melissa A Liebert,Lawrence S Sugiyama,J Josh Snodgrass,Tara J Cepon-Robins,Samuel S Urlacher,Felicia C Madimenos

doi:10.1186/s40101-016-0118-2

Abstract

BackgroundSoil-transmitted helminth (STH) infection peaks during childhood and varies by sex. The impact of market integration (MI) (increasing production for and consumption from a market-based economy) on these infection patterns, however, is unclear. In this study, STH infection is examined by sex and age among indigenous Shuar inhabiting two regions of Amazonian Ecuador: (1) the modestly market-integrated Upano Valley (UV) and (2) the more traditional Cross-Cutucú (CC) region.MethodsKato-Katz fecal smears were examined for parasite presence and infection intensity. Factorial ANOVAs and post hoc simple effects analyses were performed by sex to compare infection intensity between regions and age categories (infant/child, juvenile/adolescent, adult).ResultsSignificant age and regional differences in Ascaris lumbricoides and Trichuris trichiura infection were detected. Overall, infants/children and juveniles/adolescents displayed higher parasite loads than adults. CC females exhibited higher A. lumbricoides loads than UV females, while the opposite pattern was observed for T. trichiura infection in males.ConclusionsRegional infection patterns varied by sex and parasite species, perhaps due to MI-linked environmental and lifestyle changes. These results have public health implications for the identification of individuals at risk for infection and contribute to ongoing efforts to track changes and alleviate STH infection in indigenous populations undergoing MI.

Highlights

IntroductionThe impact of market integration (MI) (increasing production for and consumption from a market-based economy) on these infection patterns, is unclear
Soil-transmitted helminth (STH) infection peaks during childhood and varies by sex
The present study examines relationships among STH infection, age, and market integration (MI) by sex among the Shuar, an indigenous population living in the lowland region of Amazonian Ecuador

Summary

Introduction

The impact of market integration (MI) (increasing production for and consumption from a market-based economy) on these infection patterns, is unclear. The process of market integration (MI)—defined as increased production for and consumption from a marketbased economy [1, 2]—affects the health of people throughout the developing world. Infectious disease morbidity and mortality, from parasitic infection, is disproportionally high among economically developing nations in tropical regions [7]. While some such diseases, like malaria, receive significant attention from western medicine [8], the so-called neglected tropical diseases (NTDs) do not, despite being responsible for approximately 534,000 deaths annually [9]. Soil-transmitted helminths (STHs) (parasitic worms), a common type of NTD, affect over one billion people in 149 countries [9, 10]

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Conclusion