Catroxo, M. H. B.; Martins, A. M. C. R. P. F.; Petrella, S.; Souza, F.; Nastari, B.D.B.

apillomaviruses, belonging to the Papillomaviridae family, are small oncogenic viruses, causing papillomas and fibropapillomas in the mucosal and cutaneous epithelia of several animals. In bovine species, thirteen types (BPV 1-13) were characterized to date. In this study, the occurrence of papillomatosis in four outbreaks in cattle herds, coming from Brazilian states were registered. The papillomatous lesions were found located in the teats, udders, head and neck. Under the transmission electron microscope, by the negative staining technique, it was possible to visualized rounded-format papillomavirus, with icosahedral symmetry, characterized as "full" and "empty" particles, measuring on average 60 nm in diameter, in all the 40 samples observed of skin lesion fragments. The ultrathin sections revealed the presence of groups of viral, intranuclear, rounded particles measuring 35 nm in diameter and tubular particles with a diameter of 35-39 nm. At immunoelectron microscopy technique, positivity obtained was marked by the presence of aggregates of viral particles formed by the antigen-antibody interaction. In the immunocytochemistry technique, the antigen-antibody reaction showed colloidal gold particles evenly distributed over the surface of the virus. These results showed the importance of the transmission electron microscopy techniques in the diagnosis of bovine papillomatosis that can be used in routine procedures to identify viral agent of this important disease.

KEY WORDS: Papillomavirus, Cattle, Transmission Electron Microscopy.

CATROXO, M. H. B.; MARTINS, A. M. C. P. F.; PETRELLA, S.; SOUZA, F.; NASTARI, B. D. B. Ultrastructural study of bovine papillomavirus during outbraeks in Brazil. Int. J. Morphol., 31(2):777-784, 2013.