Molecular Characterization of Brazilian Infectious Bursal Disease Virus Isolated from 1997 to 2005.

The article presents information on a molecular study of Brazilian infectious bursal disease virus (IBDV) isolated from broiler and layer flocks from 1997 to 2005. Forty-one IBDV isolates were obtained from Brazilian broiler and layer flocks by reverse transcription-polymerase chain reaction (PCR), 25 of which were identified as very virulent by restriction enzyme analysis. Results of the study showed that all isolates had the typical amino acid residues and are clustered in a phylogenetic tree with the very virulent IBDV strains and that the isolates came from the same locale but were collected in different years, indicating that the strains circulating in farms in Brazil are undergoing slight but continuous exchanges.