The majority of peptic ulcers are caused by excessive intake of NSAIDs or by which infectious cause?

1. Ulcers form when the mucosal barrier breaks down and gastric juice erodes deeper into the stomach lining. 2. Two causes together account for the majority of ulcers. 3. These are excessive intake of NSAIDs, including aspirin, and infection with the bacterium Helicobacter pylori, the latter treatable with antibiotics. 4. Influenza virus and mumps (paramyxovirus) cause unrelated illnesses, and Streptococcus pyogenes is instead linked elsewhere to rheumatic fever and valvular disease, not to the majority of peptic ulcers. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 23 "The Digestive System", section 23.4, p. 1112_