Abstract

Both papillomaviruses and gammaherpesviruses have been suggested as the cause of oral and genital papillomas in bottlenose dolphins. Herpesvirus particles have been observed in both oral and genital lesions; and twenty-seven dolphin papillomavirus (DPV) types have been identified via PCR. Virus-specific PCRs for each of the known twenty-seven DPVs and the dolphin gammaherpesvirus were developed and validated.

To help clarify the association of these viruses in papillomatous lesions, 24 oral and 36 genital mucosae samples were analyzed using each of the twenty-eight virus-specific PCRs. An in situ hybridization assay was developed for DPV detection in histological sections of biopsies that had been determined to contain DPVs. Papillomaviruses and the dolphin gammaherpesvirus were all detected on both clinically normal and lesional genital mucosae. Gammaherpesvirus was also detected on three samples of non-lesional skin. However, the in situ assay did localize the DPVs in the vacuolizing cells. Multiple type DPV infections were found in almost all genital mucosae. One DPV was exclusively detected in one oral lesion. The role of DPVs, multiple type DPV infections and the dolphin gammaherpesvirus remains unclear, and the formation of genital papilloma may be multi-factorial. Until more information is generated, no virus group should be considered the exclusive cause of genital papillomas. The role of the oral DPV in formation of oral papillomas and squamous cell carcinomas warrants further investigation.