We and others have described differences in the mechanism and efficacy with which NS1 proteins control induction of IFN by influenza virus itself or by exogenous stimuli such as infection with Sendai virus or Newcastle disease virus (NDV) (Hayman et al., 2006; Jiao et al., 2008; Kochs et al., 2007; Kuo et al., 2010; Munir et al., 2011; Park et al., 2003; Wang et al., 2010). This evidence concerns the gene IFNA1 and infection.