Abstract
Objectives: Little research exists documenting levels of intestinal inflammation among indigenous populations where exposure to macroparasites, like soil-transmitted helminths (STHs), is common. Reduced STH exposure is hypothesized to contribute to increased prevalence of elevated intestinal inflammation in wealthy nations, likely due to coevolutionary histories between STHs and human immune systems that favored anti-inflammatory pathways. Here, we document levels of intestinal inflammation and test associations with STH infection among the Shuar of Ecuador, an indigenous population undergoing socioeconomic/lifestyle changes that influence their hygienic environment. We predict that fecal calprotectin (FC; a measure of intestinal inflammation) will be lower in STH infected individuals and that FC will be negatively associated with infection intensity. Methods: Stool samples to analyze FC levels and STH infection were collected from 69 Shuar participants (ages 5–75 years). Children (<15 years) and adults (15+ years) were analyzed separately to understand the role of exposure in immune system development and the intestinal inflammatory response. Results: Two species of STH were present: Ascaris lumbricoides and Trichuris trichiura. The relationships between infection and intestinal inflammation were age- and species-specific. While no significant relationships were found among adults, children who were singly infected with T. trichiura had lower FC levels than uninfected children. Infection intensity was not significantly associated with FC in children or adults. Conclusions: These preliminary results provide limited support for our hypotheses, documenting tentative age- and species-specific associations between FC and infection status. Findings may point to the importance of species-specific STH exposure during immune system development.
Original language | English (US) |
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Pages (from-to) | 65-74 |
Number of pages | 10 |
Journal | American Journal of Physical Anthropology |
Volume | 170 |
Issue number | 1 |
DOIs | |
State | Published - Sep 2019 |
Funding
The authors wish to thank the participants of this study. We declare no conflicts of interest. This research was conducted with support from the Wenner Gren Foundation, the National Science Foundation (NSF IBSS #1329091), the American Philosophical Society Lewis and Clark Fund, the Ryoichi Sasakawa Young Leaders Fellowship Fund, the University of Oregon Anthropology Department/Bray Fellowship, and the University of Colorado Colorado Springs. National Science Foundation, Grant/Award Number: 1329091; The American Philosophical Society Lewis and Clark Fund; The Ryoichi Sasakawa Young Leaders Fellowship Fund; The University of Colorado Colorado Springs; The University of Oregon Anthropology Department/Bray Fellowship; Wenner Gren Foundation
Keywords
- fecal calprotectin
- hygiene hypothesis
- inflammatory bowel disease
- old friends hypothesis
- soil-transmitted helminths
ASJC Scopus subject areas
- Anatomy
- Anthropology