Enterics are pathogens that occur normally or pathogenically in intestines of humans and other animals, sometimes resulting in diarrheal disease or food poisoning. Common bacterial causes of acute diarrhea include campylobacter, salmonella, shigella and enterotoxigenic or shiga toxin-producing E. coli. Shigella is one of the leading bacterial causes of diarrhea worldwide, while Campylobacter Jejuni is a common cause of food poisoning in Europe and the United States. Viruses are also responsible for a number of gastric illnesses. Noroviruses are a genetically diverse group of non-enveloped viruses; these are highly infectious and result in millions of cases of disease and thousands of deaths annually. Rotavirus is a genus of double-stranded RNA viruses and is the most common cause of diarrheal disease among infants and young children.