Viral
gastroenteritis symptoms may appear 1-3 days after
you are infected and
can range from mild to severe. Symptoms usually last just a day or two, but occasionally they may persist as long as 10 days. Because the symptoms are similar, it is easy to confuse diarrhea caused by viruses with diarrhea caused by bacteria (e.g., Clostridium difficile, salmonella, and E. coli) or parasites (e.g., giardia). If your symptoms persist, see your doctor for further workup and management.