title: Previous infection with virulent strains of Newcastle disease virus reduces highly pathogenic avian influenza virus replication, disease, and mortality in chickens.
abstract: Highly pathogenic avian influenza virus (HPAIV) and Newcastle disease virus (NDV) are two of the most important viruses affecting poultry worldwide and produce co-infections especially in areas of the world where both viruses are endemic; but little is known about the interactions between these two viruses. The objective of this study was to determine if co-infection with NDV affects HPAIV replication in chickens. Only infections with virulent NDV strains (mesogenic Pigeon/1984 or velogenic CA/2002), and not a lentogenic NDV strain (LaSota), interfered with the replication of HPAIV A/chicken/Queretaro/14588-19/95 (H5N2) when the H5N2 was given at a high dose (10(6.9) EID50) two days after the NDV inoculation, but despite this interference, mortality was still observed. However, chickens infected with the less virulent mesogenic NDV Pigeon/1984 strain three days prior to being infected with a lower dose (10(5.3-5.5) EID50) of the same or a different HPAIV, A/chicken/Jalisco/CPA-12283-12/2012 (H7N3), had reduced HPAIV replication and increased survival rates. In conclusion, previous infection of chickens with virulent NDV strains can reduce HPAIV replication, and consequently disease and mortality. This interference depends on the titer of the viruses used, the virulence of the NDV, and the timing of the infections. The information obtained from these studies helps to understand the possible interactions and outcomes of infection (disease and virus shedding) when HPAIV and NDV co-infect chickens in the field.
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. mar.costa-hurtado@ars.usda.gov.
authors.forename: Mar
authors.initials: M
authors.lastname: Costa-Hurtado
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. claudio.afonso@ars.usda.gov.
authors.forename: Claudio L
authors.initials: CL
authors.lastname: Afonso
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. patti.miller@ars.usda.gov.
authors.forename: Patti J
authors.initials: PJ
authors.lastname: Miller
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. eshepherd54@gmail.com.
authors.forename: Eric
authors.initials: E
authors.lastname: Shepherd
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. rami.cha@berkeley.edu.
authors.forename: Ra Mi
authors.initials: RM
authors.lastname: Cha
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. diane.smith@ars.usda.gov.
authors.forename: Diane
authors.initials: D
authors.lastname: Smith
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. erica.spackman@ars.usda.gov.
authors.forename: Erica
authors.initials: E
authors.lastname: Spackman
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. darrell.kapczynski@ars.usda.gov.
authors.forename: Darrell R
authors.initials: DR
authors.lastname: Kapczynski
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. david.suarez@ars.usda.gov.
authors.forename: David L
authors.initials: DL
authors.lastname: Suarez
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. david.swayne@ars.usda.gov.
authors.forename: David E
authors.initials: DE
authors.lastname: Swayne
authors.affiliation: Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA, USA. Mary.Pantin-Jackwood@ars.usda.gov.
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Pantin-Jackwood
mesh_terms: D000818:Animals; D002645:Chickens; D060085:Coinfection / Q000276:immunology / Q000662:veterinary / Q000821:virology; D053125:Influenza A Virus, H5N2 Subtype / Q000502:physiology*; D057920:Influenza A Virus, H7N3 Subtype / Q000502:physiology*; D005585:Influenza in Birds / Q000276:immunology* / Q000401:mortality / Q000821:virology; D009521:Newcastle Disease / Q000276:immunology* / Q000821:virology; D009522:Newcastle disease virus / Q000472:pathogenicity / Q000502:physiology*; D011201:Poultry Diseases / Q000276:immunology* / Q000401:mortality / Q000821:virology; D013047:Specific Pathogen-Free Organisms; D014774:Virulence; D014779:Virus Replication; D017201:Virus Shedding