The two most common types of stomach viruses, or gastroenteritis, are the rotavirus and the norovirus, with the norovirus ranking as slightly more common in the United States, as of 2015, according to WebMD and the Centers for Disease Control and Prevention. The norovirus belongs to the Caliciviridae family, and it was once called the Norwalk virus, states CNN.
People commonly refer to gastroenteritis as the stomach flu although it is not a flu virus, states WebMD. This ailment is a virus that causes the stomach and intestines to become irritated and inflamed, leading to symptoms such as diarrhea, nausea and vomiting, among others. People contract this virus through contact with an already infected person, by ingesting contaminated food or water, or by not washing hands after using a restroom or changing a diaper.
People contract both rotavirus and norovirus gastroenteritis by similar methods, states WebMD. Those who develop the norovirus strain commonly receive a diagnosis of acute gastroenteritis, according to the CDC. The norovirus accounts for 19 to 21 million stomach viruses in the United States annually and causes between 500 and 800 deaths, as of 2015, states CNN. The norovirus symptoms cause people to confuse it with food poisoning.