Dysplasia of the lower genital tract in the female monkey, Macaca fascicularis, the crab-eating macaque from Southeast Asia.

Seventy-eight female reproductive tracts from mature Macaca fascicularis caught in the wild were examined histologically for evidence of dysplasia in immature (metaplastic) and native (mature) squamous epithelium of the cervix and vagina. This series contained equal numbers of experimental animals and control and/or breeding colony animals. Five of 39 experimental animals showed dysplasia, whereas six animals with definite and two with questionable dysplasia were found in 39 control and breeding colony animals. On the basis of the foregoing facts, it would appear that these dysplastic lesions were of spontaneous origin and of undetermined etiology. Therefore, those investigators who experiment upon the reproductive tract of this species of monkey should be wary of interpreting any given experiment as "causing" dysplasia. Monkeys of this same species, born and reared in our Primate Center, have been examined for comparable dysplastic lesions of the lower female genital tract. None was found thus far but the study is continuing.