Viral agents that causes intestinal infections include norovirus, rotavirus, adenovirus and astrovirus. There are many bacterial species that also lead gastroenteritis like Campylobacter jejuni, Clostridium, Escherichia coli, Salmonella, Shigella, Staphylococcus, Vibrio cholerae, Yersinia, etc. Consumption of uncooked meat, unwashed or improperly washed fruits and vegetables can spread these microorganisms into the body. Many times eating stale food or spoiled food also leads to an infection.