A conventional beagle dog model for acute and chronic infection with Helicobacter pylori

Helicobacter pylori has been widely recognized as an important human pathog en responsible for chronic gastritis, peptic ulcers, gastric cancer, and mu cose-associated lymphoid tissue (MALT) lymphoma. Little is known about the natural history of this infection since patients are usually recognized as having the infection only after years or decades of chronic disease. Severa l animal models of H. pylori infection, including those with different spec ies of rodents, nonhuman primates, and germ-free animals, have been develop ed. Here we describe a new animal model in,which the clinical, pathological , microbiological, and immunological aspects of human acute and chronic inf ection are mimicked and which allows us to monitor these aspects of infecti on within the same individuals. Conventional Beagle dogs were infected oral ly with a mouse-adapted strain of H. pylori and monitored for up to 24 week s. Acute infection caused vomiting and diarrhea. The acute phase was follow ed by polymorphonuclear cell infiltration, interleukin 8 induction, mononuc lear cell recruitment, and the appearance of a specific antibody response a gainst H. pylori. The chronic phase was characterized by gastritis, epithel ial. alterations, superficial erosions, and the appearance of the typical m acroscopic follicles that in humans are considered possible precursors of M ALT lymphoma. In conclusion, infection in this model mimics closely human i nfection and allows us to study those phases that cannot be studied in huma ns. This new model can be a unique tool for learning more about the disease and for developing strategies for treatment and prevention.