Genetic reassortment of bluetongue virus serotype 11 strains in the bovine.

Reassortants of bluetongue virus Serotype 11 (BTV-11) were isolated from a yearling heifer experimentally infected with two electrophoretically different strains (UC-2 and UC-8) by subcutaneous inoculation. Viruses were recovered by direct titration of sonicated blood samples onto Vero cell monolayers, which were overlaid with agarose and later plaque purified. The parental electropherotype of UC-8 was identified as the predominant virus strain during the infection; UC-2 was not isolated. UC-2 infectivity was shown by reassortants which contained genome segments that were identical in migration pattern to the parental UC-2 electropherotype. The observations demonstrate that segmental reassortment can occur during mixed infections in the bovine, between strains of the same BTV serotype.