Experimental epididymitis and urethritis in grivet monkeys provoked by Chlamydia trachomatis.

Recently Chlamydia trachomatis has been indicated as a common cause of acute epididymitis in young men. In the present study, the grivet monkey was established as an experimental model for such infection. A yolk sac suspension of C. trachomatis, immunotype K, was inoculated into the left spermatic cords of two monkeys. On days 7 and 14 postinoculation (pi), the left testis of each monkey was enlarged to twice its normal size. The epididymis and the spermatic cord on the same side were swollen and reddened. All layers of spermatic cord were infiltrated with lymphocytes and polymorphonuclear leukocytes, and the lumen, which was filled with an exudate, was reduced in diameter. The luminar epithelium was destroyed. The ducts of the left epididymis were filled with an inflammatory exudate. The epithelium was flattened, but there were no lesions. The seminiferous tubules of the left testis were normal, but edema and hyperemia were observed in the interstitial tissue. The right spermatic cord was inoculated with noninfected yolk sac suspension. On the right side, no inflammatory reactions were seen in the testis, the epididymis, or the spermatic cord. The monkeys had a yellowish discharge 7 to 14 days pi. Urethral smears revealed an preincubation values were found.