Analogous to its role in reovirus-induced cell death, Bid is implicated in apoptosis caused by many viruses [68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79] . However, prior to our study, it was not known whether Bid modulates the pathogenesis of viral disease. The function of Bid in viral pathogenesis has been examined in a previous study, which found that the BH3-only protein, Puma, but not Bid, contributes to apoptosis-mediated elimination of antigen-specific T cells following acute infection with herpes simplex virus-1 [80] . Here, we demonstrate a pathogenic function for Bid in viral infection. Should Bid similarly modulate disease outcomes following infection by other virulent viruses, antiapoptotic compounds targeting Bid [81, 82, 83] may serve as useful antiviral therapeutics.