Gastroenteritis or infectious diarrhea is a medical condition from inflammation ("-itis") of the gastrointestinal tract that involves both the stomach ("gastro"-) and the small intestine ("entero"-). It causes some combination of diarrhea, vomiting, and abdominal pain and cramping. Dehydration may occur as a result. Gastroenteritis has been referred to as gastro, stomach bug, and stomach virus. Although unrelated to influenza, it has also been called stomach flu and gastric flu.Globally, most cases in children are caused by rotavirus. In adults, norovirus and Campylobacter are more common. Less common causes include other bacteria (or their toxins) and parasites. Transmission may occur due to consumption of improperly prepared foods or contaminated water or via close contact with individuals who are infectious. Prevention includes the use of fresh water, regular hand washing, and breast feeding especially in areas where sanitation is less good. The rotavirus vaccine is recommended for all children.The key treatment is enough fluids. For mild or moderate cases, this can typically be achieved via oral rehydration solution (a combination of water, salts, and sugar). In those who are breast fed, continued breast feeding is recommended. For more severe cases, intravenous fluids from a healthcare centre may be needed. Antibiotics are generally not recommended. Gastroenteritis primarily affects children and those in the developing world. It results in about three to five billion cases and causes 1.4 million deaths a year.