179 million cases of acute diarrhea in U.S. each year, most preventable

Herbert L. DuPont, M.D., director of the Center for Infectious Diseases at the UTHealth School of Public Health, examined current causes, prevention strategies and treatment for acute diarrhea in healthy adults. He says the main causes of diarrheal infections include norovirus outbreaks and foodborne pathogens, with most coming from contaminated leafy green vegetables.

Produce is the most common source of diarrhea due to foodborne intestinal illness. Most consumers are not aware that 98 percent of spinach and lettuce bought from grocery stores is not inspected and much of it comes from developing countries. One study showed that of the 2 percent that is inspected, 40 percent failed inspection and could be contaminated by diarrhea-producing E. coli or Salmonella.

"Consumers need to give their leafy greens a bath and a shower in order to make sure they are safe to eat," says DuPont, instructing that leafy greens must be soaked in a bowl of water or the sink and then rinsed thoroughly by running water through a colander before consumption in order to avoid contaminants.

Noroviruses are the principal cause of diarrheal infections and are responsible for 50 percent of outbreaks due to the high potential for person-to-person spread. The outbreaks are particularly common in closed populations such as cruise ships, nursing homes, dormitories and hospitals. Eighty-three percent of deaths from acute diarrhea in the U.S. occur in adults ages 65 or older who have weaker immune systems and often are residing in closed populations.

"It's important for people who are experiencing symptoms to seek medical attention if they are sick longer than 48 hours, have fever or are passing bloody diarrhea," says DuPont.

Post-diarrheal health complications are major unappreciated concerns, DuPont says. After intestinal infection, a small number of people develop chronic conditions like arthritis, irritable bowel syndrome (IBS) or even autoimmune diseases like Guillain-Barre Syndrome, a form of paralysis. These complications usually affect people who have been exposed to pathogens that cause severe intestinal inflammation in people who are sicker, younger and for IBS, in those who are already dealing with depression or a chronic anxiety disorder.

DuPont says his analysis of current treatments for acute diarrhea shows a need for antibiotic treatment for certain infections. Most currently used drugs for diarrhea treat symptoms and ease pain, but these treatments do not shorten the illness. These drugs are of particular value for those who become ill while traveling to allow people to take bus trips or flights.

Clostridium difficile-associated diarrhea, or "C diff," is one of the most prevalent causes of fatal illness from diarrhea and usually emerges during or after a hospital stay in people who take antibiotics. Our current therapy for C diff is inadequate, with high rates of recurrent disease, says DuPont. He suggests developing vaccines to provide protection against C difficile and to use fecal microbiota transplantation (putting healthy bacteria from the intestine of the ill person) for people with multiple recurrences of C diff.