Sub-serotype analysis of Guangxi isolates of infectious bursal disease virus

Hyperimmune rabbit antisera against four field isolates from Guangxi and two commonly used vaccine strains of infectious bursal disease virus(IBDV) were prepared and used against heterogeneous and homogeneous IBDV strains in the virus cross-neutralization test.Relatedness values were calculated from cross-neutralization antibody titer.The result showed that 2 subtypes were distinguished among the 6 viral strains tested.Phylogenetic analysis of the different subtypes of viruses indicated that there were divergences among the field isolates and between the isolates and the vaccine strains.The study provides a reliable scientific basis for catching up the updated antigenic variation of the field IBDV strains and developing effective vaccines against IBDV.