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Title: Experimental co-infection of SPF chickens with low pathogenicity avian influenza virus (LPAIV) subtypes H9N2, H5N2 and H7N9, and infectious bronchitis virus (IBV)

Author
item COSTA-HURTADO, MAR - Orise Fellow
item Smith, Diane
item JACKWOOD, MARK - University Of Georgia
item Spackman, Erica
item Shepherd, Eric
item Pantin Jackwood, Mary

Submitted to: International Poultry Scientific Forum
Publication Type: Abstract Only
Publication Acceptance Date: 11/10/2014
Publication Date: 1/26/2015
Citation: Costa-Hurtado, M., Smith, D.M., Jackwood, M., Spackman, E., Shepherd, E.M., Pantin Jackwood, M.J. 2015. Experimental co-infection of SPF chickens with low pathogenicity avian influenza virus (LPAIV) subtypes H9N2, H5N2 and H7N9, and infectious bronchitis virus (IBV) [abstract]. 2015 International Poultry Scientific Forum, January 26-27, 2015, Atlanta, Georgia. CDROM.

Interpretive Summary:

Technical Abstract: Avian influenza virus (AIV) and infectious bronchitis virus (IBV) are two of the most important respiratory viruses affecting poultry worldwide, but little is known about the effect of co-infection of these two viruses in poultry. Low pathogenicity (LP) AIV can produce from mild to moderate upper respiratory disease that can be exacerbated by other factors in the field. Since commercial poultry is routinely vaccinated with live IBV vaccines we evaluated the dynamics of LPAIV-IBV co-infections and their effect on disease outcome in chickens. Four-week-old specific pathogen free (SPF) white leghorn chickens were intraocular and intranasally inoculated with a live IBV Mass vaccine strain and with one of three different subtype LPAIV’s: A/chicken/Egypt/12/2013 (H9N2), A/chicken/HK/2212982/2014 (H7N9), and A/chicken/Mexico-Coahuila/IA20/11/2011 (H5N2), by simultaneous or sequential inoculation (LPAIV given 3 days after IBV). Viruses were also given individually. No clinical signs were observed in any of the experimental groups. However, differences in the titers of virus shed by the oropharyngeal route were observed and depended on the LPAIV strain used. No effect on H5N2 LPAIV shedding was observed in co-infected birds, this virus being shed in high titers from all inoculated birds. However, birds previously or simultaneously inoculated with IBV shed higher titers of the H9N2 LPAIV when compared to the single LPAIV infected birds. On the other hand, lower titers of the H7N9 LPAIV were shed by birds previously infected with IBV, but titers were higher in birds simultaneously inoculated with both viruses when compared to single LPAIV-inoculated birds. In conclusion, the effect of co-infection of chickens with IBV and LPAIV varies depending on the LPAIV and the timing of co-infection, with exacerbation, reduction, or no effect on virus shedding.