title: A Real-Time Reverse-Transcription Polymerase Chain Reaction for Differentiation of Massachusetts Vaccine and Brazilian Field Genotypes of Avian Infectious Bronchitis Virus.
abstract: The avian infectious bronchitis virus is classified into serotypes or genotypes (or both) in different poultry-producing countries of the world. In Brazil, Massachusetts type (Mass), used as a live vaccine, and local field Brazilian variants (genotypes; BR) predominate in the commercial poultry flocks. This study describes the development and validation of two real-time reverse-transcription polymerase chain reactions (RT-qPCR) for the specific detection of Mass and BR genotypes in allantoic fluids and clinical samples. Genotype-specific primers, combined with a generic probe targeted to the S1 gene, originated Mass RT-qPCR and BR RT-qPCR-specific assays. Analytical sensitivity and linearity of these assays were determined in comparison with an IBV generic real-time RT-PCR based on the 5' untranslated region (5'UTR RT-qPCR). Mass RT-qPCR detected five Mass field isolates, three vaccine samples, and one coinfected sample (BR and Mass) while BR RT-qPCR detected 16 BR field isolates. Both assays were linear (R(2) > 0.98), reproducible, and as sensitive as the classical 5'UTR RT-qPCR used to detect IBV. In the analysis of 141 IBV clinical samples, 8 were positive for Mass RT-qPCR, 76 for BR RT-qPCR, and 2 for both assays. In the remaining 55 samples, 25 were positive only for 5'UTR RT-qPCR and 30 were negative for the three assays. In conclusion, both assays were able to detect Mass and BR genotypes, allowing rapid and easy IBV molecular typing from allantoic fluids and clinical samples.
authors.affiliation: A Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil - ULBRA, Canoas, 92425-900, Rio Grande do Sul, Brazil.|B Simbios Biotecnologia, Cachoeirinha, 94940-030, Rio Grande do Sul, Brazil.
authors.forename: Aline Padilha de
authors.initials: AP
authors.lastname: Fraga
authors.affiliation: A Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil - ULBRA, Canoas, 92425-900, Rio Grande do Sul, Brazil.|B Simbios Biotecnologia, Cachoeirinha, 94940-030, Rio Grande do Sul, Brazil.
authors.forename: Nilo
authors.initials: N
authors.lastname: Ikuta
authors.affiliation: B Simbios Biotecnologia, Cachoeirinha, 94940-030, Rio Grande do Sul, Brazil.
authors.forename: André Salvador Kazantzi
authors.initials: AS
authors.lastname: Fonseca
authors.affiliation: C Universidade FEEVALE, Novo Hamburgo, 93352-000, Rio Grande do Sul, Brazil.
authors.forename: Fernando Rosado
authors.initials: FR
authors.lastname: Spilki
authors.affiliation: A Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil - ULBRA, Canoas, 92425-900, Rio Grande do Sul, Brazil.
authors.forename: Eder
authors.initials: E
authors.lastname: Balestrin
authors.affiliation: A Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil - ULBRA, Canoas, 92425-900, Rio Grande do Sul, Brazil.
authors.forename: Carolina Dias
authors.initials: CD
authors.lastname: Rodrigues
authors.affiliation: D Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, 91540-000, Rio Grande do Sul, Brazil.
authors.forename: Cláudio Wageck
authors.initials: CW
authors.lastname: Canal
authors.affiliation: A Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil - ULBRA, Canoas, 92425-900, Rio Grande do Sul, Brazil.|B Simbios Biotecnologia, Cachoeirinha, 94940-030, Rio Grande do Sul, Brazil.
authors.forename: Vagner Ricardo
authors.initials: VR
authors.lastname: Lunge
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D002645:Chickens; D018352:Coronavirus Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D005838:Genotype; D001351:Infectious bronchitis virus / Q000235:genetics* / Q000276:immunology*; D016133:Polymerase Chain Reaction / Q000662:veterinary*; D011201:Poultry Diseases / Q000453:epidemiology* / Q000821:virology; D017422:Sequence Analysis, DNA / Q000662:veterinary; D014613:Vaccines, Attenuated / Q000235:genetics; D014765:Viral Vaccines / Q000235:genetics*
chemical_list: D014613:Vaccines, Attenuated; D014765:Viral Vaccines
keywords: Brazil; IBV; diagnosis; infectious bronchitis virus; molecular typing; variant