Key take aways on diarrhea

• Diarrhea kills around 1.5 million people every year.⁵⁵ It is the third cause of death in children under 5.¹
   
• Most cases of acute diarrhea are due to infectious pathogens, i.e. viruses, bacteria, parasites. Rotavirus and Escherichia coli are the two most common etiological agents of moderate-to-severe diarrhea in low-income countries.¹

• Whatever the etiological agent of infectious diarrhea, the outcome depends on complex interplays between the pathogen and the gut microbiota.
   
• The composition of the gut microbiota can shape the outcome of an infection by a diarrheal pathogen, and be either a protective or a facilitating factor. In turn, the diversity and composition of gut microbiota can be severely altered by infectious diarrhea and a return to a "healthy microbiota" may require several weeks after diarrhea has resolved.¹⁴

• A significant proportion of diarrheal disease can be prevented through safe drinkingwater and adequate sanitation and hygiene.¹
   
• Rotavirus vaccination is another important preventive strategy, which the WHO recommends be included in all national immunization programmes and considered as a priority.⁵⁶

• The majority of infectious diarrheas are self-limiting in immunocompetent individuals. Nevertheless, some patients (with severe dehydration, more severe illness, persistent fever, bloody stools, immunosuppression…) require specific diagnostic investigation.¹¹
   
• The most important complication of infectious diarrhea is dehydration, which may require oral or intravenous fluid replacement therapy, depending on the degree of dehydration.¹

Both the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) and the World Gastroenterology Organization (WGO) consider that some probiotic strains can be recommended by HCP:

• for the prevention of antibiotic-associated diarrhea;
• for the treatment of acute (viral) diarrhea in children, as they may shorten diarrhea duration.

• Future research should expand microbiome knowledge in the context of infectious diarrheas, in order to improve their prevention and management.
   
• The optimization of microbiota profile in order to shape infectious outcomes⁵ and improve rotavirus vaccine efficacy²⁹ represents a promising research path.