Gastroenteritis viruses: A = rotavirus, B = adenovirus, C = norovirus and D = astrovirus. The virus particles are shown at the same magnification to allow size comparison.
Gastroenteritis is usually caused by viruses;[4] however, gut bacteria, parasites, and fungi can also cause gastroenteritis.[2][4] In children, rotavirus is the most common cause of severe disease.[10] In adults, norovirus and Campylobacter are common causes.[11][12] Eating improperly prepared food, drinking contaminated water or close contact with a person who is infected can spread the disease.[2] Treatment is generally the same with or without a definitive diagnosis, so testing to confirm is usually not needed.[2]
For young children in impoverished countries, prevention includes hand washing with soap, drinking clean water, breastfeeding babies instead of using formula,[2] and proper disposal of human waste. The rotavirus vaccine is recommended as a prevention for children.[2][10] Treatment involves getting enough fluids.[2] For mild or moderate cases, this can typically be achieved by drinking oral rehydration solution (a combination of water, salts and sugar).[2] In those who are breastfed, continued breastfeeding is recommended.[2] For more severe cases, intravenous fluids may be needed.[2] Fluids may also be given by a nasogastric tube.[13]Zinc supplementation is recommended in children.[2]Antibiotics are generally not needed.[14] However, antibiotics are recommended for young children with a fever and bloody diarrhea.[1]
In 2015, there were two billion cases of gastroenteritis, resulting in 1.3 million deaths globally.[6][7] Children and those in the developing world are affected the most.[15] In 2011, there were about 1.7 billion cases, resulting in about 700,000 deaths of children under the age of five.[16] In the developing world, children less than two years of age frequently get six or more infections a year.[17] It is less common in adults, partly due to the development of immunity.[18]