[1] Helicobacter pylori (H. pylori) is by far the best known Helicobacter species primarily because humans infected with it may develop gastrointestinal tract diseases such as stomach inflammation, stomach ulcers, duodenal ulcers, stomach cancers of the non-lymphoma type, and various subtypes of extranodal marginal zone lymphomass, e.g. those of the stomach, small intestines, large intestines, and rectum.

H. pylori is also associated with the development of bile duct cancer and has been associated with a wide range of other diseases although its role in the development of many of these other diseases requires further study.

[4][6]) H. heilmannii s.s. bacteria are detected in the stomachs of their natural hosts viz., cats, dogs, foxes, lynxes, and non-human primates.

Reports suggest that individuals, including children,[5] are infected with this bacterium by having close contact with one of these animals:[4] H. heilmannii s.l.-associated diseases, including those associated with H. heilmannii s.s., appear to be zoonotic diseases, i.e., infectious diseases that are caused by pathogens that spread from animals to humans.

[4] It is important to diagnose H. heilmannii as well as the other Helicobacter heilmannii sensu lato infections in patients with the cited upper gastrointestinal tract diseases, including in particular extranodal marginal zone lymphoma of the stomach, because some of them have been successfully treated and cured using antibiotic-based drug regimens (e.g.amoxicillin, clarithromycin, plus a proton pump inhibitor[7] such as lansoprazole,[8] or metronidazole, clarithromycin, plus a proton pump inhibitor[4]) directed against the instigating bacterium.