title: Pathogenicity of infectious bronchitis virus isolates from Ontario chickens.
abstract: Infectious bronchitis (IB) is one of the important viral diseases of chickens, and in spite of regular vaccination, IB is a continuous problem in Canadian poultry operations. In an earlier study using sentinel chickens we determined the incidence of infectious bronchitis virus (IBV) in Ontario commercial layer flocks. The objective of this study was to determine the pathogenicity of 5 nonvaccine-related IBV isolates recovered from the sentinel birds. The clinical signs, gross, and histological lesions in specific pathogen-free chickens indicated that all 5 isolates caused mild lesions in the respiratory tract. An important finding of this study was the significantly lower average daily weight gain among virus-inoculated groups of chickens during the acute phase of infection. Based on sequences of part of the S1 gene IBV-ON2, IBV-ON3, and IBV-ON5 formed a cluster and they were closely related to strain CU-82792. IBV-ON4 had 98.7% identity with the strain PA/1220/9, a nephropathogenic variant.
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph.
authors.forename: Helena
authors.initials: H
authors.lastname: Grgić
authors.forename: D Bruce
authors.initials: DB
authors.lastname: Hunter
authors.forename: Peter
authors.initials: P
authors.lastname: Hunton
authors.forename: Eva
authors.initials: E
authors.lastname: Nagy
mesh_terms: D000818:Animals; D002645:Chickens; D016000:Cluster Analysis; D018352:Coronavirus Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D005260:Female; D005838:Genotype; D015994:Incidence; D001351:Infectious bronchitis virus / Q000302:isolation & purification / Q000472:pathogenicity*; D008297:Male; D009864:Ontario / Q000453:epidemiology; D011201:Poultry Diseases / Q000453:epidemiology / Q000821:virology*; D011897:Random Allocation; D016415:Sequence Alignment; D013047:Specific Pathogen-Free Organisms; D014132:Trachea / Q000473:pathology / Q000821:virology; D014611:Vaccination / Q000662:veterinary; D015430:Weight Gain
chemical_list: D004279:DNA, Viral