[Experimental infection of guinea pigs with Chlamydia. 1. Pathomorphological studies]

The changes that occurred following nasal instillation of a bovine strain of Chlamydia psittaci were characterized by hypertrophy and proliferation of epithelial cells and exudates containing polymorphonuclear leukocytes, with acute bronchopneumonia and less intense inflammatory reactions in nasal and tracheal mucosa, spleen and pulmonary lymph nodes. The intestines, liver, kidney and brain were scarcely affected. There was little prospect of complete recovery from the clinically mild, or even subclinical, pneumonia within the period of observation since the causal agent was present continuously from the 12th hour to the 91st day after infection.