Abstract
1) Two spontaneous cases of a disease probably caused by Chlamydia were recognized among cynomolgus monkeys (Macaca irus) imported from the Philippines. They were diagnosed as such from light- and electron-microscopic findings. The diagnosis was also supported by the results of serological and virological examinations. 2) The two cases were pathologically characterized by pleuropneumonia and the ulceration of the tongue and lips. In the electron-microscopic examination, numerous reticulate bodies and elementary bodies were recognized in the cytoplasm of epithelial cells in the lesion of tongue ulcer which contained inclusion bodies observed by light microscopy. Furthermore, Chlamydia-like particles were seen in the lungs.
