Short answers, pulled from the story.
Total deaths from diarrhea were estimated at 1.53 million in 2019, down from 2.9 million in 1990. The World Health Organization reports that diarrheal disease deaths fell by 45 percent between 2000 and 2021, dropping from the sixth leading cause of death globally to the thirteenth.
Rotavirus is the most common cause of diarrhea in children under five, accounting for roughly 40 percent of cases in that age group. In adults, norovirus takes that position as the leading cause of viral diarrhea.
Oral rehydration solution, or ORS, is the WHO-recommended treatment for diarrhea. A WHO-endorsed homemade version consists of one liter of clean water with one teaspoon of salt (about three grams) and two tablespoons of sugar (about eighteen grams), which approximates what the WHO describes as "the taste of tears."
Hand washing with soap and water has been experimentally shown to reduce the incidence of diarrhea by approximately 30 to 48 percent. Access to soap remains a barrier in many less developed countries, limiting the reach of this intervention.
Diarrhea is defined by the World Health Organization as three or more loose or liquid stools per day. Dysentery is a specific form in which blood is visible in the stool, signaling that bowel tissue has been invaded; it is associated with pathogens including Shigella, Entamoeba histolytica, and Salmonella.
Oral rehydration solution combined with zinc tablets has been estimated to have saved 50 million children over the past 25 years. UNICEF widely distributes packets of salts and sugar for this purpose, and commercial solutions such as Pedialyte serve the same function.