The evolution of bluetongue virus serotype 17.

Four serotypes of bluetongue virus (BTV-10, 11, 13 and 17) have been identified in the United States. Analyses of the genome RNA segments and viral induced polypeptides of U.S. prototype BTV-17 virus by comparison with the corresponding macromolecules of earlier isolates of BTV-11 serotype support the hypothesis that BTV-17 originated by genotypic and antigenic drift from a BTV-11 serotype virus.