Helicobacter felis is a bacteriumspecies in the Helicobacteraceae family, Campylobacterales order, Helicobacter genus. This bacterium is Gram-negative, microaerophilic, urease-positive, and spiral-shaped. Its type strain is CS1T. It can be pathogenic. Helicobacter pylori is by far the best known Helicobacter species primarily because humans infected with it may developgastrointestinal tractdiseases such as stomach inflammation, stomach ulcers, doudenal ulcers, stomachcancers of the non-lymphoma type, and various subtypes of extranodal marginal zone lymphomass, e.g. those of the stomach, small intestines, large intestines, and rectumn. 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. Humans infected with H. felis may also develop some of the same gastrointestinal diseasesviz., stomach inflammation, stomach ulcers, duodenum ulcers, stomach cancers that are not lymphomas, and extrnodal marginal B cell lymphomas of the stomach. Other non-H. pylori Helicobacter species that are known to be associated with these gastrointestinal diseases are Helicobacter bizzozeronii, Helicobacter salomonis, Helicobacter suis, and Helicobacter heilmannii s.s. Because of their disease associations, these four Helicobacter species plus H. felis are often group together and termed Helicobacter heilmannii sensu lato. H. felis bacteria are detected in the stomachs of their natural hosts viz.,cats, dogs, rabbits, and cheetahs. Reports suggest that individuals, including children, are infected with this bacterium by having close contact with one of these infected animals: H. heilmanni s.l.-associated diseases, including those associated with H. felis, appear to be zoonotic diseases, i.e. infectious diseases that are caused or promoted by a pathogen that spreads from animals to humans. It is important to diagnose H. felis as well as 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 directed against the instigating bacterium.
