The coexistence of multiple bluetongue virus electropherotypes in individual cattle during natural infection.

Evidence of multiple genotypes of bluetongue virus (BTV) serotype 11 simultaneously infecting individual cattle was demonstrated in a California sentinel herd naturally infected with two BTV serotypes (11 and 17). Monitoring of weekly virus isolates by PAGE demonstrated genome segment diversity among BTV serotype 11 isolates and an individual bull simultaneously infected with multiple electropherotypes of this serotype. No electrophoretic variations were apparent in BTV serotype 17 isolates. The results of this study indicate that multiple plaque clonings and comparative electrophoresis are required to analyse BTV field isolates accurately for the presence of mixed infections.