Abstract
Urogenital carcinoma is a common cause of morbidity and mortality in California sea lions (Zalophus californianus, CSLs).5 Multiple factors have been associated with the development of urogenital carcinoma in CSLs, including genetic factors, otarine herpesvirus-1 infection, and organochlorines.1,2,7,9 Arising from the genital tissue, most notably the cervix and vagina of females and the penis and prepuce of males,3,7 urogenital carcinoma is often aggressive and is characterized by widespread metastasis.5,7 Early genital lesions are often characterized by carcinoma "in situ" and intraepithelial neoplasia.3,7 Urogenital carcinoma metastasis can lead to severe clinical disease, including paresis, paralysis, rectal prolapse, and hydroureter.5 To the authors' knowledge, there is currently no specific ante-mortem diagnostic test for urogenital carcinoma in the CSLs, and neoplasia is often diagnosed late in the disease progression, after severe clinical signs have developed.5 In humans, the cervicovaginal cytology screening test ("Pap" test) is considered the standard of care screening method for preneoplastic and neoplastic cervical diseases, as this screening test has been directly associated with the significant decrease in morbidity and mortality associated with neoplastic cervical disease.10
Cervical and vaginal cell cytology has been described in some marine mammal species, but is most often used to improve reproductive efficiency.6,8 There is some cytologic evidence that vaginal epithelial abnormalities could be attributed to pre-cancerous lesions in the CSL,11 but as the cervical and vaginal epithelium may undergo hormone-related changes during the reproductive cycle, further evaluation is warranted.4 The purpose of this work was to characterize normal cervical and proximal vaginal cytology and to determine if cervicovaginal cytology could be used as a simple ante-mortem screening test for urogenital carcinoma in CSLs. Subadult and adult female CSLs were opportunistically sampled at the time of necropsy throughout the reproductive cycle. Closed and open body cavity proximal vaginal and cervical cytology samples were collected using cotton-tipped applicators. Closed body cavity sampling was performed with the use of swab guards to ensure proximal vaginal or cervical cell sampling. Cytology samples were stained with Wright-Giemsa stain and evaluated via light microscope. Normal and abnormal cell morphology was characterized. Histopathologic sampling and evaluation was used to confirm individual reproductive stage and to determine if individuals were affected by urogenital carcinoma at the time of death. Sampling is ongoing.
* Presenting author
+ Student presenter
Literature Cited
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