|Costa Hurtado, Mar - Orise Fellow|
Submitted to: International Symposium on Avian Influenza
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2015
Publication Date: 4/12/2015
Citation: Costa Hurtado, M., Afonso, C.L., Miller, P.J., Shepherd, E.M., Smith, D.M., Pantin Jackwood, M.J. 2015. Previous infection with a mesogenic strain of Newcastle disease virus affects infection with highly pathogenic avian influenza viruses in chickens [abstract]. 9th International Symposium on Avian Influenza, Athens, Georgia. p.87.
Technical Abstract: Avian influenza virus (AIV) and Newcastle disease virus (NDV) are two of the most important viruses affecting poultry worldwide, but little is known on the interactions between these two viruses when infecting birds. In a previous study we found that infection of chickens with a mesogenic strain of NDV (mNDV) could prevent subsequent infection with a highly pathogenic (HP) AIV, consequently protecting against disease and mortality. To determine the minimum dose of mNDV required to protect chickens against HPAIV infection, 2-week-old birds were inoculated with different doses of mNDV (10^4, 10^5 or 10^6 embryo infective dose (EID)50) followed 3 days later by inoculation with an HPAIV (10^5 or 10^6 EID50). Although birds co-infected with the higher mNDV doses (10^5 or 10^6) survived for longer than birds inoculated only with HPAIV (10^5), we did not observe the same protection with the lower dose of mNDV (10^4) or when given the higher dose of HPAIV (10^6), indicating that the titer of the viruses are determinant in the viral interference observed. We also examined the duration of protection provided by a high dose of mNDV (10^7 EID50) on HPAIV infection. Five-week-old chickens were inoculated with mNDV followed by inoculation with 10^6 EID50 of an HPAIV given 2, 4, 6, and 9 days after the mNDV. Surprisingly, an increase in survival was found in all co-infected groups when compared to the HPAIV single-inoculated group. In conclusion, previous inoculation with mNDV can affect HPAIV replication in chickens for more than a week but this viral interference is titer dependent.