Oncogenic papillomavirus-like particles in Angelfish (Pterophyllum scalare) from Iran

Investigation of fish neoplasms is one of the most important topics in aquaculture research. In addition to the necessity of this kind of research on edible fish (as excellent sources of protein), those with significant economic role should be attended as well. An ornamental fish with visible tumors is not a proper one to sell, therefore looking for causative agents and prevention methods also in some cases treatment, is required. In this study, swellings on the lips of 100 specimens of Angelfish (Pterophyllum scalare) were analyzed through histopathological method with preparing histology slides using hematoxylin and eosin (H&E) and also Masson’s Trichrome staining techniques and examined by light microscope. Electron microscopy was also used to observe the virus particlesIn the histopathological investigation, the smooth and cauliflower-like tumor lesions were identified with both characteristics of fibroma and papilloma known as fibropapilloma. Moreover, the interpreted results of electron micrographs declared the existence of papillomavirus-like particles. Given that the environmental carcinogenic factors and other oncogenic infectious agents are among the suspects of neoplasia causers in the aquatic ecosystems, based on the outcomes of the present research, papillomavirus-like agents were identified as the culprit of neoplasia in studied specimens of P. scalare which could be a notice for the aquaculture industry to take more considerations than ever, on the biosafety and health-protective issues including filtration, disinfection, water quality control and using the broodstocks free of oncogenic agents, to be immune from neoplasm.