title: Characterization of nephropathogenic infectious bronchitis virus DMV/1639/11 recovered from Delmarva broiler chickens in 2011.
abstract: A limited outbreak of nephropathogenic infectious bronchitis (NIB) occurred in three Delmarva (DMV) commercial broiler chicken flocks in 2011. Isolates of NIB virus (NIBV)--DMV/1639/11, DMV/3432/11, and DMV/3902/11--were characterized by sequence analysis of the N-terminal subunit (S1) of the spike (S) gene. Findings indicated that the isolates were identical to each other and to PA/9579A/10, a 2010 isolate from poultry in Pennsylvania. The 2010 and 2011 isolates appear to have originated from a 1997-2000 NIB outbreak in Pennsylvania. DMV/1639/11 and PA/9579A/10 were determined to be nephropathogenic in susceptible chickens, yielding virus reisolations from kidney and inducing characteristic interstitial nephritis microscopic lesions. In a controlled laboratory study, 40% of chickens vaccinated with a combination live vaccine containing infectious bronchitis virus (IBV) strains Massachusetts (Mass) + Connecticut (Conn) were positive on virus isolation attempts after challenge with DMV/1639/11, compared with only 13% of Mass + Arkansas (Ark) vaccinates. Both combination vaccines gave partial protection against the development of DMV/1639/11-induced renal lesions. Although numerically fewer chickens vaccinated with Mass + Conn had interstitial nephritis compared with those vaccinated with Mass + Ark, neither vaccine combination offered greater protection (P < 0.05) than observed in unvaccinated chickens challenged with DMV/1639/11. Mass + Ark vaccinations, applied under commercial conditions in the hatchery (spray) and on-farm (spray), did not protect the trachea or kidney from DMV/1639/11 challenge. Serologic testing of broiler flocks found < 3% (2 of 69) tested to possess specific antibodies to DMV/1639/11, indicating the virus had not become established in the region.
authors.affiliation: Avian Biosciences Center, University of Delaware, Department of Animal and Food Sciences, Newark, DE 19716-2150, USA. jgelb@udel.edu
authors.forename: Jack
authors.initials: J
authors.lastname: Gelb
authors.forename: Brian S
authors.initials: BS
authors.lastname: Ladman
authors.forename: Conrad R
authors.initials: CR
authors.lastname: Pope
authors.forename: J Miguel
authors.initials: JM
authors.lastname: Ruano
authors.forename: Erin M
authors.initials: EM
authors.lastname: Brannick
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Bautista
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Coughlin
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Preskenis
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002645:Chickens; D018352:Coronavirus Infections / Q000453:epidemiology / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D003691:Delaware / Q000453:epidemiology; D001351:Infectious bronchitis virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D007668:Kidney / Q000473:pathology / Q000821:virology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011201:Poultry Diseases / Q000453:epidemiology / Q000517:prevention & control / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D017422:Sequence Analysis, DNA / Q000662:veterinary; D020539:Sequence Analysis, Protein / Q000662:veterinary; D017385:Sequence Homology; D013047:Specific Pathogen-Free Organisms; D017778:Vaccines, Combined / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology*; D014774:Virulence
chemical_list: D000914:Antibodies, Viral; D017778:Vaccines, Combined; D014765:Viral Vaccines