title: Experimental co-infections of domestic ducks with a virulent Newcastle disease virus and low or highly pathogenic avian influenza viruses.
abstract: Infections with avian influenza viruses (AIV) of low and high pathogenicity (LP and HP) and Newcastle disease virus (NDV) are commonly reported in domestic ducks in many parts of the world. However, it is not clear if co-infections with these viruses affect the severity of the diseases they produce, the amount of virus shed, and transmission of the viruses. In this study we infected domestic ducks with a virulent NDV virus (vNDV) and either a LPAIV or a HPAIV by giving the viruses individually, simultaneously, or sequentially two days apart. No clinical signs were observed in ducks infected or co-infected with vNDV and LPAIV, but co-infection decreased the number of ducks shedding vNDV and the amount of virus shed (P<0.01) at 4 days post inoculation (dpi). Co-infection did not affect the number of birds shedding LPAIV, but more LPAIV was shed at 2 dpi (P<0.0001) from ducks inoculated with only LPAIV compared to ducks co-infected with vNDV. Ducks that received the HPAIV with the vNDV simultaneously survived fewer days (P<0.05) compared to the ducks that received the vNDV two days before the HPAIV. Co-infection also reduced transmission of vNDV to naïve contact ducks housed with the inoculated ducks. In conclusion, domestic ducks can become co-infected with vNDV and LPAIV with no effect on clinical signs but with reduction of virus shedding and transmission. These findings indicate that infection with one virus can interfere with replication of another, modifying the pathogenesis and transmission of the viruses.
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA 30605, USA. Electronic address: Mary.Pantin-Jackwood@ARS.USDA.gov.
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Pantin-Jackwood
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA 30605, USA.
authors.forename: Mar
authors.initials: M
authors.lastname: Costa-Hurtado
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA 30605, USA.
authors.forename: Patti J
authors.initials: PJ
authors.lastname: Miller
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA 30605, USA.
authors.forename: Claudio L
authors.initials: CL
authors.lastname: Afonso
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA 30605, USA.
authors.forename: Erica
authors.initials: E
authors.lastname: Spackman
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA 30605, USA.
authors.forename: Darrell R
authors.initials: DR
authors.lastname: Kapczynski
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA 30605, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Shepherd
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA 30605, USA.
authors.forename: Diane
authors.initials: D
authors.lastname: Smith
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA 30605, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Swayne
mesh_terms: D000818:Animals; D060085:Coinfection / Q000662:veterinary; D004372:Ducks / Q000821:virology; D009980:Influenza A virus / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000821:virology*; D009521:Newcastle Disease / Q000821:virology*; D009522:Newcastle disease virus / Q000472:pathogenicity*; D014774:Virulence; D017201:Virus Shedding
keywords: Avian influenza virus; Co-infections; Domestic ducks; Newcastle disease virus; Viral interference