Enteric parasitic infections: From environmental enteric dysfunction to gut microbiota and childhood malnutrition

Malnutrition accounts for high morbidity and mortality in children. Specifically, linear growth failure (stunting)has long-term consequences. It affects approximately 25% of children under the age of five worldwide andhas been linked to increased mortality, cognitive dysfunction, and productivity loss. Understanding that asignificant proportion of stunting is not caused solely by lack of nutrition, diarrhea, and repeated exposure tointestinal infections implies that other factors must be analyzed to clarify continued growth faltering. Entericparasitic infections are prevalent in many tropical environments and are linked to poor nutritional statusand growth stunting. Environmental enteric dysfunction (EED) is an undefined syndrome characterizedby inflammation, decreased absorptive capacity, and impaired barrier function in the small intestine. Thedysfunction has been allied to malnutrition, as well as oral vaccine failure causing delayed developmentin children from poor resource settings. This syndrome might be triggered by unhygienic environmentalconditions that cause frequent exposure to fecal pathogens and decreased nutrient absorption. Additionally,childhood malnutrition was strongly linked to changes in the gut microbiome. Motivation for the presentreview was the relatively obscure cumulative effect of repeated enteric parasitosis on nutritional statusof children in developing countries from various perspectives. Accordingly, intestinal parasites infections,EED, and microbiota alteration are all likely issues that must be concurrently addressed. Addressing allthese conditions would resolve the grave public health issues of malnutrition and infection susceptibility,and consequently, lead to application of behavioral and therapeutic policies among vulnerable pediatricpopulations.