Diarrheal disease and enteric infections in LMIC communities: how big is the problem?

Abstract

Studies of enteric diseases have historically focused on observations of clinical diarrhea as a cause of mortality and morbidity. Emerging evidence suggests that diarrhea dramatically underestimates both exposure to enteropathogens and the long-term consequences arising from infection. High burden of pathogens in the gut, even in the absence of diarrhea, is common in infants in low and middle income countries. Continual challenge by pathogens, in conjunction with an inadequate diet stimulates an inflammatory disease that alters the structure of the gut, metabolic and immunological pathways and changes the microbiome. Both diarrhea and enteropathogen infection have been associated with reduced growth, reduced cognitive development, and reduced vaccine efficacy suggesting that the burden of diarrheal disease is dramatically underestimated.

Keywords: Cognitive development; Diarrhea; Enteric pathogens; Enteropathy; Growth; Malnutrition; Sanitation and hygiene; Vaccine response.

Fig. 1

The conceptual model of the “vicious cycle of poverty”, linking enteric infections to gut dysfunction, impaired nutrient absorption, malnutrition and restricted physical and cognitive development. Stages within this cycle are described in the text

Fig. 2

a) The percentage of DALYs in children under 5 years old due to diarrheal disease based on the 2013 Global Burden of Diarrhea estimates [95]; b) the percentage of children stunted based on data collated by UNICEF, WHO, World Bank showing the most recent national data available for each country (ranging from 2006 to 2015) [96]