Submitted to: American Association of Avian Pathologists
Publication Type: Abstract only
Publication Acceptance Date: 1/10/2014
Publication Date: 7/26/2014
Citation: Costa-Hurtado, M., Afonso, C.L., Miller, P.J., Shepherd, E.M., Smith, D.M., Pantin Jackwood, M.J. 2014. Host antiviral defenses induced by a mesogenic strain of Newcastle disease virus prevents infection with a highly pathogenic avian influenza virus in chickens [abstract]. American Association of Avian Pahologists Annual Meeting, July 26-29, 2014, Denver, Colorado. CD-ROM. Interpretive Summary:
Technical Abstract: Avian influenza virus (AIV) and Newcastle disease virus (NDV) are two of the most important viruses affecting poultry worldwide. Co-infections of poultry with AIV and NDV are a problem from both the clinical point of view and the diagnosis of these viruses. To evaluate the dynamics of AIV-NDV co-infections, specific pathogen free (SPF) white leghorn chickens were co-infected with a mesogenic strain of NDV (mNDV) (Pigeon 84) and with a HPAIV (A/chicken/Jalisco/CPA-12283-12/2012 H7N3) by simultaneous or sequential inoculation. We found that previous infection of chickens with mNDV can prevent infection with HPAIV 3 days later, consequently protecting against disease and mortality due to HPAIV. To understand the mechanism of the viral interference observed, different immune-modulators were evaluated. Cytokines, including IFN-a, IFN-ß, IFN-', IL-6, IL-1ß and IL-2 were determined at different time points in sera and spleen lysates taken from chickens infected with mNDV. Differences in the activation profile of immune cells from blood, lung and spleen were also assessed. The results were then compared with the protection attained against HPAIV infection at the different time points after mNDV infection. We found that when mNDV has replication advantage is able to interfere with a HPAIV infection by inducing an antiviral state due to the activation of innate immune mechanisms. In conclusion, previous infection with mNDV can interfere with HPAIV infection; however, the innate immune response induced by the mNDV depends on the levels of virus replication in tissues which will affect the outcome observed.