Environmental enteropathy

Environmental enteropathy, also known as tropical enteropathy or environmental enteric dysfunction (EED), is a condition or subclinical disorder believed to be due to frequent intestinal infections.[1] There are often minimal acute symptoms.[1] There may be chronic problems with absorbing nutrients which may result in malnutrition and growth stunting in children.[1] It may be the chronic form of tropical sprue which is usually brief and presents with diarrhea.[1] Environmental enteropathy results in a number of changes in the intestines including: smaller villi, larger crypts (called crypt hyperplasia), increased permeability, and inflammatory cell build-up within the intestines. These changes result in poor absorption of food, vitamins and minerals – or "modest malabsorption".[2]

Signs and symptoms

Environmental enteropathy is believed to result in chronic malnutrition and subsequent growth stunting (low height-for-age measurement) as well as other child development deficits. Especially the first two years (and the prior 9 months of fetal life) are critical for linear growth and maybe even more importantly brain development. Stunting is an easy to measure symptom of these child development deficits, and the effects have been found to be mostly irreversible. Furthermore, contrary to the negative impacts of diarrheal episodes on the growth of children below the age of two, which can usually be overcome in between these episodes (given adequate nutrition), the chronic effects of environmental enteropathy are not recovered from easily.[3]

Effect on oral vaccination

Many oral vaccines, both live and non-living, have proven to be less immunogenic or less protective when administered to infants, children or adults living in low socioeconomic conditions in developing countries than they are when used in industrialized countries. Widespread environmental enteropathy is hypothised to be one of the causes for this.[4][5]

Cause

An important cause of environmental enteropathy is most likely the constant exposure of children to their own and other people's fecal bacteria if the children live in an environment characterised by widespread open defecation and lack of sanitation like in many informal settlements in developing countries.[2]

Mechanisms

Environmental enteropathy results in a number of changes in the intestines including: smaller villi, larger crypts (called crypt hyperplasia), increased permeability, and inflammatory cell build-up within the intestines. These changes result in poor absorption of food, vitamins and minerals – or "modest malabsorption".[2]

History

The term "environmental enteropathy" was first used in 1984 by Fagundes-Neto to describe a syndrome that includes non-specific histopathological and functional changes of the small intestine in children of poor families living in conditions lacking basic sanitary facilities and chronically exposed to fecal contamination. The term was introduced to replace the previously term "tropical enteropathy" (sometimes also "tropical jejunopathy") as the condition described is not only found in tropical areas and is believed to be caused by environmental factors.[6]

References

  1. 1 2 3 4 Korpe, PS; Petri WA, Jr (June 2012). "Environmental enteropathy: critical implications of a poorly understood condition.". Trends in molecular medicine. 18 (6): 328–36. doi:10.1016/j.molmed.2012.04.007. PMC 3372657Freely accessible. PMID 22633998.
  2. 1 2 3 Humphrey, JH (2009). "Child undernutrition, tropical enteropathy, toilets, and handwashing.". Lancet. 374 (9694): 1032–5. doi:10.1016/s0140-6736(09)60950-8. PMID 19766883.
  3. ↑ Prendergast, Andrew; Kelly, Paul (2012). "Review: Enteropathies in the Developing World: Neglected Effects on Global Health". Am. J. Trop. Med. Hyg. 5 (85): 756–763. doi:10.4269/ajtmh.2012.11-0743.
  4. ↑ Levine, Myron M (4 October 2010). "Immunogenicity and efficacy of oral vaccines in developing countries: lessons from a live cholera vaccine". BMC Biology. 8 (129). doi:10.1186/1741-7007-8-129. Retrieved 14 November 2014.
  5. ↑ Haque, Rashidul (16 January 2014). "Oral polio vaccine response in breast fed infants with malnutrition and diarrhea". Vaccine. 32 (4): 478–482. doi:10.1016/j.vaccine.2013.11.056. Retrieved 30 September 2015.
  6. ↑ Fagundes-Neto, Ulysses; Viaro, Tania; Wehba, Jamal; Patricio, Francy Reis da Silva; Machado, Nelson Lourenço (1984). "Tropical enteropathy (environmental enteropathy) in early childhood: a syndrome caused by contaminated environment.". Trop Pediatr. 4 (30): 204–209. doi:10.1093/tropej/30.4.204. Retrieved 14 November 2014.

External links

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