Brazilian avian metapneumovirus subtypes A and B: experimental infection of broilers and evaluation of vaccine efficacy

Pesquisa Veterinária Brasileira

Márcia B. Dos Santos²  Matheus C. Martini²  Helena L. Ferreira¹  Luciana H.a. Da Silva²  Paulo A. Fellipe²  Fernando R. Spilki¹  Clarice W. Arns² 

[1] ,Universidade Estadual de Campinas Instituto de Biologia Laboratório de VirologiaCampinas SP ,Brazil

关键词: Avian metapneumovirus;    in vivo replication;    vaccine protection;    Metapneumovirus aviário;    replicação in vivo;    proteção vacinal;   

DOI  :  10.1590/S0100-736X2012001200008

来源: SciELO

【 摘 要 】

Avian metapneumovirus (aMPV) is a respiratory pathogen associated with the swollen head syndrome (SHS) in chickens. In Brazil, live aMPV vaccines are currently used, but subtypes A and, mainly subtype B (aMPV/A and aMPV/B) are still circulating. This study was conducted to characterize two Brazilian aMPV isolates (A and B subtypes) of chicken origin. A challenge trial to explore the replication ability of the Brazilian subtypes A and B in chickens was performed. Subsequently, virological protection provided from an aMPV/B vaccine against the same isolates was analyzed. Upon challenge experiment, it was shown by virus isolation and real time PCR that aMPV/B could be detected longer and in higher amounts than aMPV/A. For the protection study, 18 one-day-old chicks were vaccinated and challenged at 21 days of age. Using virus isolation and real time PCR, no aMPV/A was detected in the vaccinated chickens, whereas one vaccinated chicken challenged with the aMPV/B isolate was positive. The results showed that aMPV/B vaccine provided a complete heterologous virological protection, although homologous protection was not complete in one chicken. Although only one aMPV/B positive chicken was detected after homologous vaccination, replication in vaccinated animals might allow the emergence of escape mutants.

【 授权许可】

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