A stomach virus (or stomach flu) is not a form of influenza but a condition that causes the stomach and intestines to become inflamed, resulting in a variety of uncomfortable, digestive-related symptoms. Stomach "flu" is universal, and for most people a private, and usually temporary, annoyance. The symptoms are nausea in the stomach, aches, fever and vomiting. The infectious agent is either a virus, bacterium or parasite.
According to the U.S. National Library of Medicine, there are many types of viruses that can cause this condition, chiefly: