Genetic diversity of bovine papillomavirus types, including two putative new types, in teat warts from dairy cattle herds

Teat papillomatosis affects dairy cows worldwide. Milking can become difficult due to teat warts, and maintaining affected cows in the herds may diminish economic profit in the dairy industry. Currently, 13 bovine papillomavirus (BPV) types have been fully characterized, and numerous putative BPV types have been identified through partial L1 gene PCR. In order to identify the viral types present in warts on the udders of dairy cows, 40 teat lesions from 24 cows from 13 cattle farms in three States of Brazil were evaluated by PV L1 gene PCR. The warts that were evaluated contained sequences from BPVs 6-10, the putative BPV types BAPV9 and BAPV4, and two unreported putative papillomavirus (PV) types, named BPV/BR-UEL6 and BPV/BR-UEL7. In addition, mixed infections and coinfections were identified, since more than one lesion was observed on the udders of 13 cows. Phylogenetic analysis showed that BPV/BR-UEL6 is closely related to BPVs belonging to the genus Xipapillomavirus, while BPV/BR-UEL7 clustered with the previously reported strains Cervus timorensis and Pudu puda PVs, which represent a putative new PV type, and it was only distantly related to xi-, epsilon-, delta- and dyoxi-PVs. These results provide information that will assist in the understanding of the association of BPVs 6, 7, 8, 9, and 10, as well as putative BPV types BAPV4 and BAPV9, with mammary papillomatosis. This is the first characterization of putative novel PV types BPV/BR-UEL6 and BPV/BR-UEL7 in teat warts of dairy cows, highlighting the high genetic diversity of BPVs associated with teat papillomatosis.