ABSTRACT
Introduction .................................................................................................................................. 151 Helicobacter Species and Diseases.................................................................................... 151 Purposes and Choice of the Animal Model....................................................................... 153
Animal Models of H. pylori Infection ........................................................................................ 153 Nonhuman Primate Models................................................................................................ 153 Nonprimate Models ............................................................................................................ 156
Mouse Model.......................................................................................................... 156 Mongolian Gerbil Model........................................................................................ 158 Gnotobiotic Piglet Model ....................................................................................... 162 Other Animal Models ............................................................................................. 162
Differences Between H. pylori-Infected Animal Models and Human Disease ......................... 162 Future Perspectives ...................................................................................................................... 163 References .................................................................................................................................... 163
INTRODUCTION
Helicobacter Species and Diseases
The genus Helicobacter comprises a group of microaerophilic Gram-negative spiral to curved bacteria isolated from the stomachs, intestines, and hepatobiliary tracts of humans and animals.1-6
The type species of the genus, Helicobacter pylori, has been recognized in humans as the most common cause of gastroduodenal diseases.7 Helicobacter pylori infections occur in human populations throughout the world, and the prevalence of infection increases with age. Infection occurs at an early age (i.e., childhood) and is more prevalent among individuals in developing countries than among those in developed countries.8 More than half the individuals in developed (middle to old age) and developing (all age) countries are infected in adulthood, and H. pylori infection is one of the most common bacterial infections in humans. Once acquired, the infection becomes chronic and persists for life unless treated, but most individuals infected with H. pylori
remain asymptomatic for decades.9 Although the primary route of H. pylori infection remains poorly understood, it is suggested that fecal-oral or oral-oral transmission may occur via water, food, or the nursing process.10,11 Helicobacter pylori infection is a significant risk factor for peptic ulcer disease (gastric and duodenal ulcer), and moreover, chronic atrophic gastritis and intestinal metaplasia following chronic superficial gastritis are risk factors for adenocarcinoma of the stomach, since the prolonged inflammation accompanying H. pylori infection might contribute to the development of this malignancy.12,13 In addition, this bacterium may play a role in the development of low-grade B-cell lymphomas of gastric mucosa-associated lymphoid tissue (MALT lymphoma).14
