Papillomavirus in yaks: the isolates of bovine papillomavirus type 1 have a high possibility of belonging to a novel type

Although papillomaviruses (PVs) have been widely reported in vertebrates, there have been only a few PV reports in yaks (Bos grunniens). In 2012, Bam et al. reported bovine papillomavirus type 1 (BPV-1) and BPV-2 associated with cutaneous papillomatosis in yaks, which provided genomic and pathology information for yak PVs. However, nucleotide identity and phylogenic analyses revealed that there are two isolates with a high possibility of belonging to a novel type that is not BPV-1. The argument was thought to be caused by type-specific primers. Our analysis showed that BPV-1 type-specific primers can detect not only BPV-1 but also other PVs. It suggests that identification results using type-specific primers should be confirmed with more robust methods in molecular epidemiological studies.