What Is Stomach Flu?
Officially called gastroenteritis, stomach flu is an infection of the digestive system -- and is totally unrelated to the regular flu (influenza), which affects the respiratory system. Stomach flu is the second most common illness kids get, after respiratory infections like colds. Although unpleasant, stomach flu is usually not serious. It's usually caused by viruses, but can also come from bacteria like salmonella and E. coli, as well as some parasites.
Stomach flu causes inflammation of a child's stomach and digestive tract, usually triggering vomiting, diarrhea, and fever. "Babies and young children are especially prone to infection because their immune systems are still forming, so they haven't yet built up the antibodies to fight off germs," says Rita Steffen, MD, a pediatric gastroenterologist at the Cleveland Clinic in Cleveland, Ohio.