In the latest report, chronic infection with the bacterium known as Helicobacter pylori, or H. pylori, has been listed as known to be a human carcinogen. H. pylori is a spiral bacteria that can enter the body through food, water or utensils, lives in the digestive tract and is behind most stomach ulcers. It is thought to penetrate the mucous lining of the stomach to establish infection and can lead to stomach cancer. It is more commonly found in countries with less established infrastructures surrounding clean water and sewage systems, but spread from one person to another is possible through saliva or other bodily fluids.