CASP3 and infection: We, and others, have previously reported that influenza virus induces apoptosis upon infection.10, 31, 32, 33 Moreover, influenza virus induces cell death through the apoptotic pathway and not by necrosis.31, 32, 33 In further support of this, we reported that viral infection resulted in the activation of several factors of the intrinsic apoptotic pathway,10 including PARP, a substrate of caspase-3.