337 Bulletin UASVM, Veterinary Medicine 67(1)/2010 ISSN 1843-5270; Electronic ISSN 1843-5378 Identification of Helicobacter pylori Infection from the Gastric Samples of Dogs with Gastritis Lesion by Immunohistochemical Method Marian TAULESCU, Adrian GAL, Pompei BOLFA, Raouad MOUSSA, Andras NAGY, Flaviu TABARAN, Gabriel BORZA, Cosmina CUC, Lidia CIOBANU, Cornel CATOI University of Agriculture Sciences and Veterinary Medicine, Faculty of Veterinary Medicine, Pathology Department, 3-5 Calea Mănăştur Street, Cluj-Napoca, Romania taulescumarian@yahoo.com Abstract. Helicobacter pylori represents one of the most common and medically prominent infections worldwide. Infection with these bacteria has an association with histological gastritis, gastric atrophy, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach in dogs and cats. Chronic infection of dogs with Helicobacter infection is characterized by an infiltration of polymorphonuclear and mononuclear cells and frequently with hypertophy of limphoid follicles in the gastric mucosa. The aim of this study was to identify the Helicobacter pylori infection by immunohistochemical method from dogs with gastritis lesions. The most common types of specific gastritis were chronic gastritis characterized by an inflammatory infiltrate with lymphocytes, macrophages and plasma cells in the lamina propria of the gastric mucosa, atrophy of the gastric glands, fibrous tissue proliferation and hypertrophy of limphoid follicles in gastric mucosa. Immunohistochemical method identified the Helicobacter pylori infection on the surface layer of gastric epithelium and lumen glands in five dogs. Keywords: Helicobacter pylori, chronic gastritis, dogs, immunohistochemistry. INTRODUCTION In 1983, Warren and Marshall proposed the possible association of Helicobacter pylori infection with peptic ulcer disease and gastric cancer in humans. Approximately 50% of the world's population is infected with Helicobacter pylori, with a greater prevalence in developing countries (7). Dogs can be experimentally infected with H. pylori, but there are limited sources of gastric infection pathology in dogs. A study reporting H. pylori-like organism in gastric mucosa of dog suggested the possibility of the natural transmission of infection between humans and dogs. Helicobacter pylori are pathogen for dogs, at least in experimental conditions and that the acute lesions caused in dogs are similar to those in others animal models – superficial neutrophilic gastritis and ulcers (2). The presence of gastric Helicobacter-like organisms (HLO) in the stomachs of dogs has been known for many years, but the relationship of these organisms to gastric disease is unresolved, with inflammation accompanying infection in some but not all infected dogs (3, 4). Infection with HLO is highly prevalent in dogs; it is seen in 61–80% of dogs presented for the investigation of vomiting, 67–86% of clinically healthy pet dogs, and almost 100% of laboratory Beagles and shelter dogs (3). The natural infection in dogs with Helicobacter pylori is contested, but there are authors whom identified this bacteria using PCR method from the mucosa gastric of dogs (H. pylori positive at three cases in dogs) (1). Other authors identified the bacteria from dog’s feces using special kit for H. pylori antigen. Using this