Detection, isolation and molecular characterization of bovine respiratory syncytial virus (BRSV) in field samples

Author(s)

Helena Gallicchio Domingues

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2005-05-07

Examining board members

Clarice Weis Arns; Maria Silvia Viccari Gatti; Tomomasa Yano; Domingos da Silva Leite; Aramis Augusto Pinto; Maria da Gloria Buzinaro

• Advisor: Clarice Weis Arns

Abstract

In this study techniques to detect the bovine respiratory syncytial virus (BRSV), aiming at the diagnosis and molecular characterization of this pathogen, where adapted and applied in samples collected from animals regardless of the presence of clinical signs and symptoms characteristic of infections caused by this agent. A total of 278 samples of nasal secretion and pulmonary fragments of bovine herds from the States of São Paulo and Rio Grande do Sul. By using the RT-PCR technique it was detected the presence of BRSV in seven samples, two of the nasal secretion samples, and five of the pulmonary fragments samples. The positive samples were submitted to viral isolation, and a new isolate named BRSV-108-BR was obtained after nine passages in cell cultivations. 603 pb fragments corresponding to the genomic segment of the G protein of the BRSV samples in study and obtained through the RT-PCR technique were submitted to restriction enzyme analysis (REA) and sequencing, aiming at their molecular characterization. With the REA technique, genetic variations were identified among the detected BRSV samples, suggesting that two samples belonged to the BSRV AB subgroup and five belonged to the BRSV B subgroup. However, phylogenetic analysis carried out by sequence alignment obtained with sequences available at the GeneBank revealed that all samples detected belonged to subgroup B. With this study we suggest that the REA technique to classify BRSV subgroups has a limited usefulness, serving only as a prior instrument to characterize the samples. Nevertheless, a subsequent analysis based on G protein sequencing is extremely necessary to characterize samples in one of the different BRSV existing subgroups (AU)