Target Tissues Associated with Genital Infection of Female Guinea Pigs by the Chlamydial Agent of Guinea Pig Inclusion Conjunctivitis

Female guinea pigs were experimentally infected in the genital tract with the strain of Chlamydia psittaci that causes guinea pig inclusion conjunctivitis. Chlamydiae were found frequently in superficial squamous epithelial cells of the exocervix, along with heavy involvement at the squamocolumnar junction. In this zone chlamydiae were observed in columnar cells, but inflammation and chlamydial inclusions were not observed in true endocervical epithelium. These observations were supported by results of immunofluorescence microscopy. Electron micrographs revealed typical chlamydiae within surface epithelial cells at the squamocolumnar junction; various stages of the growth cycle (elementary, reticulate, and intermediate bodies) were also present. Cytopathologic features were not remarkable, but peripheral distribution of organelles, rarefaction of the cytoplasm, and loss of microvilli were observed. Interest in human genital infections caused by the chlamydial organism Chlamydia trachomatis has increased in recent years [1-3]. At present no convenient experimental animal model system is available for the study of genital infections caused by C. trachomatis. In our laboratory, a system has been developed using guinea pigs and the agent of guinea pig inclusion conjunctivitis (GPIC), a Chlamydia psittaci organism discovered by Murray in 1964 [4]. Experimental infection of female guinea pigs, production of conjunctivitis in newborns, and infection of males with subsequent transmission to females have been reported [5, 6]. Female-to-male infection