H. pylori is contagious and transmittable through saliva, according to The University of Arizona College of Public Health. It is also transmittable through food and water that have been contaminated by feces or fecal bacteria.
H. pylori progression is very slow and may take decades, according to the University of Arizona College of Public Health. H. pylori produces a chemical called urease that is able to survive in the stomach by neutralizing stomach acid. When combined with urea in the body, urease can form ammonia, which is toxic to cells. H. pylori may be the cause of stomach acid overproduction.