The present study includes isolation and identification of the dog's Cestoda Taenia hydatigena from the small intestine of the stray dogs in Basrah city. Mice Balb/ c were infected by feeding 1-2 gravid segments segment/ mice. Five mice were killed after one, two and three months post infection. The histological sectioning of liver showed infiltration of inflammatory cells and a clear vacuolation of hepatocytes after one month. Minimal diffuse vacuolation of hepatocytes and barnachymal focus of mononuclear cells were observed after two and three months of feeding. In the spleen, prominent white palp lymphoid tissues associated with lymphofolical formation were noticed after one month of infection. An extramedullary haematopoesis and presence of megakaryocytes were noticed after two months of infection with a lymphoid hyperplasia of white palp lymphoid tissue after three months of infection. In the lungs a prominent perbronchiolar lymphoid tissue were found after one month of infection. Areas of alveolar emphysema with bronchiolar epithelial hypertrophy and proliferation besides prominent per bronchiolar lymphoid tissue were seen after two months of infection. After three months of infection an advance of bronchi pneumonia with a presence of mixed inflammatory cells in bronchioles and alveoli and bronchiolites with intraluminar inflammatory cells, hypertrophy and proliferation of bronchiolar epithelium, and congestion with emphysema were observed. Also a pulmonary alveolar edema was found in lung of mice after three months of infection. The small Intestine has changes like infiltration of inflammatory cells in lamina propria in mice after one month of infection. While, at two months post infection a moderate infiltration of mixed inflammatory cells in the lamina propria with evidence of papillary proliferation in villa structure were recorded. After three months of infection, an increase in the number of inflammatory cells in lamina propria was seen.
Key words: Bronchi Pneumonia, Extramedullary haemopoesis, Inflammatory cells, Taenia hydatigena