Comparison of MNV-S99 and MNV-1.CW3 replication under treatment with 10 U/ml IFN or with 100U/ml IFN-β revealed that the propagation of the non-persistent strain MNV-1.CW3 was inhibited significantly more and viral titers were lower 48 hpi as compared to MNV-S99 infections (Fig 2). The gene discussed is IFNB1; the disease is infection.