Interaction of Giardia intestinalis and Systemic Oxidation in Preschool Children in the Western Highlands of Guatemala.

Guatemala is a country with the highest prevalence of stunting in under-5 children in the Americas, with a national average of 49.8%. Asymptomatic intestinal colonization with Giardia intestinalis is common in Guatemalan preschoolers and has been implicated as a factor in linear growth retardation. The potential mechanisms of any giardiasis-growth interaction have not been exhaustively explored.

The aim of the present study was to describe urine oxidative stress biomarkers and erythrocyte antioxidant enzyme activity, and to explore any association with prevalence or intensity of G intestinalis infection in preschoolers attending 3 government-subsidized day care centers in the Guatemalan Western Highlands.

Samples of feces, urine, and red blood cell (RBC) hemolysate were collected in a total of 74 preschoolers enrolled in 3 day care centers. Giardia prevalence and a proxy index for intensity were assessed by enzyme-linked immunosorbent assay (ELISA). Urinary biomarkers of oxidative damage to DNA (8-hydroxydeoxyguanosine [8-OHdG]) and to lipid (F2t 15-Isoprostane [F2-Iso]) were measured by ELISA. The erythrocyte activity of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GSR), and glutathione peroxidase (GPX) were measured by respective spectroscopic substrate-based reaction assays.

Median values of RBC CAT activity (P = 0.016) and urine F2-Iso (P = 0.023) differed between children who were positive (n = 39) and negative (n = 35) for Giardia. Similarly, G intestinalis intensity was significantly and positively associated with urinary F2-Iso (r = 0.446, P < 0.001), RBC SOD (r = 283, P = 0.014), and RBC CAT (r = 0.260, P = 0.025).

The optical density reading of the fecal ELISA assay for G intestinalis has potential as a proxy for the intensity of infestation. In this respect, there exists an association of this intensity with indicators of the systemic oxidation.