This may have been because there was insufficient NSDV/GV protein at the time of the NDV superinfection to provide a complete block of the IFN induction pathway inside each infected cell; the reduction in reporter gene activity was indeed less pronounced if NDV was applied after shorter periods of GV or NSDV infection such as four hours post infection (data not shown), showing that it takes some time for the active block of the IFN induction pathway to take effect. The gene discussed is IFNA1; the disease is infection.