With great interest I read your article, which adresses the important question on the role of contaminating sequences in reference genomes. However, in this paragraph I see two points that need clarification. First, Bovine Herpesvirus 6 (also termed bovine lymphotropic herpesvirus) has not yet been associated with disease in cattle. Instead it has been identified in blood samples of a high proportion of asymptomatic cattle (for reference see Rovnak J, et al., J Virol. 1998 May;72(5):4237-42). Second, Bovine herpesvirus 6 belongs to the family herpesviridae, and not to the family retroviridae. The latter show a mechanism of host genome integration using a virus encodes reverse transcriptase. This is not the case for herpesviruses, although host genome integration has been assumed to occur in some herpesviruses by a still unknown mechanism. Clearly, designating Bovine herpesvirus 6 a retrovirus is misleading.