In contrast to other viral infections (17), IFN-α or IFN-β production in response to influenza infection was unaltered (Fig. 1B) at a time point (day 2 p.i.)previously demonstrated to represent the time of significant A/X-31 influenza virus-induced type 1 IFN secretion in this model (26). This evidence concerns the gene IFNA1 and viral infectious disease.