Bovine respiratory syncytial virus

Bovine respiratory syncytial virus (BRSV) is a major cause of respiratory disease, mainly in young cattle, characterized by interstitial pneumonia. Distribution of BRSV infections is worldwide and the virus has been identified in different episodes in Brazil. The virus belongs to the genus Pneumovirus of the Paramyxoviridae family and its negative sense non-segmented RNA genome encodes 10 proteins. Fusion (F) and attachment (G) proteins constitute the main target for immune responses of the host. This fact may be related to the great variability of these proteins and its corresponding genes among field isolates, as determined by both monoclonal antibodies and phylogenetic analysis using nucleotide sequences. Transmission, immune responses and pathogenesis of BRSV infections were studied in the natural host under natural and experimental conditions; however, some aspects regarding the immunobiology of infection are yet poorly understood. The use of experimental models of infection, especially rodents, may provide new information on these subjects. The present status on laboratory diagnosis of infections and control measures to prevent BRSV outbreaks are also presented and discussed.