By far, the most common cause of acute diarrhea is an infection with a virus. This is known as viral gastroenteritis or, more commonly, "the stomach flu."
Many types of viruses can cause diarrhea. Common types of stomach flu viruses include:
- Rotavirus, which is the most common cause of diarrhea in children
Other viral diarrhea causes include infections with one of the following:
- Norovirus, which is a common cause of cruise ship diarrhea (norovirus gastroenteritis). The first norovirus identified was known as the Norwalk virus.
- Herpes simplex virus.
- Viral hepatitis.
Several types of bacteria can cause acute diarrhea. These include:
- Staphylococcus aureus (S. aureus) -- A common contaminant of processed meats and custard-filled pastries.
- Clostridium perfringens -- A common contaminant in foods that have been warmed on steam tables.
- Bacillus cereus -- A common contaminant of rice and bean sprouts.
- Salmonella species -- A contaminant of eggs and poultry. Typhoid fever is an infection caused by the Salmonella typhi bacterium.
- Shigella -- This bacterium is common in daycare settings and in rural villages in developing countries.
- Escherichia coli (E. coli) -- Undercooked or raw hamburger has been implicated in many of the documented outbreaks of E. coli; however, outbreaks have also involved:
- Alfalfa sprouts
- Unpasteurized fruit juices
- Dry-cured salami
- Game meat
- Cheese curds.
- Campylobacter jejuni -- A contaminant of poultry. It is also found in household pets.
- Yersinia enterocolitica -- A bacterium that causes an infection known as yersiniosis. This infection is caused by eating infected meat or dairy products.
- Vibrio parahaemolyticus -- An infection with this bacterium often results from eating raw seafood, especially oysters.