Antigenic and Genetic Characteristics of the Akabane Viruses Isolated from Sentinel Cattle in Okayama Prefecture

Abstract

A serological survey conducted in Okayama Prefecture from September to November, 2001, revealed that 35% of the farms and 27.6% of sentinel calves investigated were positive for antibodies to the Akabane virus (AKAV). The virus was isolated from erythrocytes and blood plasma of a sentinel calf in late September. As a result of the cross-neutralization (NT) test, the isolates demonstrated various antigenic relationships to the reference (JaGAr39) strain and a distinct antigenic relationship with a highly virulent AKAV known as the Iriki strain. SRNA sequence data identified the isolate as the same as reported AKAVs. Phylogenetic analysis with known AKAVs put the isolate in the cluster that includes the Iriki strain, but in a very divergent position. These results suggest that the isolate may be a new genotype.