According to the World Health Organization (WHO) diarrhoeal disease is the second leading cause of death and high morbidity in children under five years old. Every year, around 525 000 children die of diarrhoeal disease (1). As diarrhoeal episodes usually follow the ingestion of contaminated food or water, children and individuals living in low- and middle-income countries are particularly at risk. It is estimated that currently about 780 million people lack access to improved drinking-water and 2.5 billion lack improved sanitation (1).
Figure 1. Mortality due to ETEC (A) and Shigella (B) diarrhoea and other infectious diseases in children younger than 5 years, by WHO region. Other infectious diseases are all other deaths from infections caused by ETEC-induced and Shigella-induced stunting. AFRO=African Region, AMRO=Region of the Americas, EMRO=Eastern Mediterranean Region, EURO=European Region, SEARO=Southeast Asian Region, WPRO=Western Pacific Region. Reproduced from Anderson JD, et al. Lancet Glob Health 2019. Copyright © 2019 The Author(s).
Shigella and enterotoxigenic Escherichia coli (ETEC) are among the leading causes of diarrhoea worldwide. In low- and middle-income countries these pathogens account for about 200 million episodes of diarrhoea per year and are directly or indirectly responsible for about 107 500 annual deaths in children under 5-year age (Figure 1) (2). The African region and the South Eastern Asian region have the highest percentage of ETEC episodes, while most Shigella cases occur in the African region, Eastern Mediterranean region and Southern Asian region (Figure 1 and 2) (2). For those surviving infections, it has been observed that prolonged and/or repeated symptomatic episodes in childhood can have long term consequences such as reduced cognitive development, poorer educational outcomes, reduced wages and increased risk of non-communicable diseases in adulthood, further perpetuating the cycle of poverty in low-resource settings (3).
Figure 2: Total ETEC and Shigella deaths (A-B) in 79 countries. Estimates include deaths from direct cases of ETEC and Shigella plus other infectious disease deaths caused by ETEC-induced and Shigella-induced stunting. Reproduced from Anderson JD, et al. Lancet Glob Health 2019. Copyright © 2019 The Author(s).
Conventional treatment includes rehydration therapy and the use of antibiotics. However, given the emergence of multi-drug resistance strains of ETEC and Shigella the development of alternative interventions is becoming increasingly imperative.
(1) World Health Organization: https://www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease
(2) Anderson JD, Bagamian KH, Muhib F, Amaya MP, Laytner LA, Wierzba T, Rheingans R (2019) Burden of enterotoxigenic Escherichia coli and shigella non-fatal diarrhoeal infections in 79 low-income and lower middle-income countries: a modelling analysis. Lancet Glob Health 7: e321–30.
(3) Guerrant RL, DeBoer MD, Moore SR, Scharf RJ, Lima AA (2013) The impoverished gut--a triple burden of diarrhoea, stunting and chronic disease. Nat Rev Gastroenterol Hepatol. 10(4):220-9.