Molecular characterization of avian infectious bronchitis virus strains from outbreaks in Argentina (2001–2008)

Abstract

Twenty infectious bronchitis virus isolates were recovered from broilers and layers in different outbreaks amongst commercial poultry flocks in different geographic regions of Argentina from 2001 to 2008. The viruses were isolated from the tracheas, lungs, and caecal tonsils of birds that were showing respiratory signs. Further analysis based on their nucleotide and amino acid sequences in hypervariable region (HVR) 1 and the intervening sequence including HVRs 1 and 2 (HVR1/2) of the S1 gene was done to determine the genetic relationships among them and reference strains. Five isolates were highly related to the Massachusetts or Connecticut serotypes, indicating the probability of the detection and isolation of vaccine strains. The other Argentinean isolates formed three separate clusters (A, B and C), distant from the vaccine serotypes, with no correlation between the generated clusters and a geographic pattern. These observations could explain the failure of the Massachusetts serotype vaccination programmes to control IBV in these flocks. In addition, the utilization of HVR1/2 and HVR1 sequences resulted in trees with similar topology but the phylogenetic relationships using HVR1/2 nucleotide sequences were better supported by higher bootstrap values. Therefore, the sequences of the HVR1/2 region are recommended for phylogenetic studies.

The genotyping of Infectious bronchitis virus in Taiwan by a multiplex amplification refractory mutation system reverse transcription polymerase chain reaction

“…3,19 An IBV infection generally lasts for 3-10 days, thus an effective and rapid typing of IBV outbreaks, even in vaccinated flocks, is beneficial and will help with the conducting of the proper procedures needed to control the spread of the disease. 3,26 Although serotyping of IBV can be achieved by hemagglutination inhibition, virus neutralization, and enzymelinked immunosorbent assays, nucleic acid-based methods remain feasible options because of their advantages of reliability and rapidity. 20 As a possible alternative to restriction enzyme digestion, hybridization, or nucleotide sequencing, reverse transcription polymerase chain reaction (RT-PCR) has been developed to detect IBV.…”

Genotipificación de variantes del virus de bronquitis infecciosa aviar en el departamento del Tolima, Colombia

“…In the study of Acevedo et al (14), this isolate was grouped in the same clade of the M41 strain, in which HT6 also grouped.Therefore, it is believed that the HT6 strain may have been an isolated of vaccine strain. The isolation of vaccine strain in chickens with IB symptoms can be related to the virulence reversion of live attenuated vaccine which may cause dissemination and persistence of the vaccine virus (24), or even with the immunosuppression of birds with consequent increased vaccine reactions, resulting in clinical signs compatible with IB (10). In a study of phylogenetic relationship in Argentina, vaccine strains were also isolated in the country and they were grouped in the same cluster of the Massachusetts strains (10).…”

“…Otros países como Brasil, Argentina, Australia y Túnez, también pasan por la misma situación. Estrategias de vacunación usando las vacunas autorizadas para el control de la BI han resultado inefectivas debido a la circulación de nuevos genotipos (7)(8)(9)(10)(11)(12). Por lo tanto, después de la identificación de los genotipos de campo (VBI), es importante la implementación de planes de control adecuados, usando cepas vacunales específicas para ofrecer protección contra la enfermedad.…”

“…The isolated from Brazil (13), Cuba (14) and Argentina (10) were also used to evaluate the phylogenetic relationship with the samples from Colombia. The GeneBank accession numbers of IBV variants are: IBV/Brazil/SC02 (GQ169247), IBV/Brazil/PR07 (GQ169244), I B V / B ra z i l / S P 0 2 ( G Q 1 6 9 2 5 0 ) , C u b a / L a inserción en la región S1 de la zona hipervariable (4).…”

“…Vaccine strategies using licensed vaccines to control the IB have been ineffective, due to the circulation of new genotypes (7)(8)(9)(10)(11)(12). Therefore, after identifying the IBV field genotypes it is important to implement appropriate control plans, using specific vaccine strains for each region in order to offer protection against the disease.…”