Behavior

• H. pylori releases enzymes that neutralize stomach acid. It weakens the protective coating of the stomach and small intestine so stomach acid and H. pylori affect the sensitive lining underneath.
  
  

Prevalence

• About 20 percent of people younger than 40 years old in the United States and 50 percent of those older than 60 are infected with H. pylori, according to the NIH. It is prevalent worldwide as well, affecting about half the people globally.
  
  

Asymptomatic Infection

• Most people with H. pylori do not develop ulcers, and many never learn they have the infection. If the bacteria is identified through a blood test and no symptoms are occurring, health care practitioners generally do not treat the infection.
  
  

Treatment

• Patients with ulcers who are diagnosed with an H. pylori infection are treated with two types of antibiotics along with a stomach acid-suppressing medication such as omeprazole (Prilosec) or cimetidine (Tagamet). Bismuth medications also are beneficial because they protect the stomach lining and kill some of the H. pylori bacteria.
  
  

Contagion

• Researchers are not sure how people contract H. pylori bacteria, according to the NIH, but it likely is through contaminated food or water.