Additional file 4: of Previous infection with virulent strains of Newcastle disease virus reduces highly pathogenic avian influenza virus replication, disease, and mortality in chickens Costa-HurtadoMar AfonsoClaudio MillerPatti ShepherdEric ChaRa SmithDiane SpackmanErica KapczynskiDarrell SuarezDavid SwayneDavid Pantin-JackwoodMary 2015 Study 3: average distribution of NDV-NP antigen by IHC. Tissues from chickens inoculated simultaneously or sequentially with mNDV and with a HPAIV. Single and simultaneously infected groups were analyzed at 2 dpi and at 2 days after inoculation with the HPAIV in groups sequentially infected (bird 1/bird 2).