Norovirus is the most common infectious agent that causes acute gastroenteritis. However, it is important to remember that norovirus is not the only cause of acute gastroenteritis. It is estimated that norovirus may cause more than 23 million gastroenteritis cases every year in the United States, representing approximately 60 percent of all acute gastroenteritis cases. According to CDC, “institutional settings such as hospitals and LTCFs commonly report outbreaks of norovirus gastroenteritis, which may make up over 50 percent of reported outbreaks.