Isolation And Identification Of Infectious Bursal Disease Virus

Infectious bursal disease(IBD)is an acute and highly contagious infectious disease,caused by infectious bursal disease virus(IBDV).IBDV mainly against chicken bursa of fabricius B lymphocyte in the organization,and make the decrease in the number of B cells,cause severe immunosuppression,leading to immune failure and induce secondary infection.In recent years,IBD epidemic strains continue to produce new mutations.This study from a region of Fujian suspected IBD chicken Fabricius bursa and spleen tissues and successfully isolated from a strain of the virus,by chicken embryo culture,RT-PCR,gene sequencing,animalregression test method of the virus were identified,the results are as follows:1.After inoculation of chick chorioallantoic membrane,the symptoms of hemorrhage in the head and extremities were occurred,the half chicken embryo lethal dose(EID50)is 10-4.5/0.2mL.2.In animal regression test,the infected SPF chicken thigh and breast muscle hemorrhage,bursa of Fabricius,spleen swelling hemorrhage.3.The sequencing analysis showed that,the strains and reference medium partial strong virulence vaccine strains of nucleotide and deduced amino acid sequence homology with high,respectively 98.7%-99.0%,99.0%-99.5%,heptapeptide are for SWSASGS and virulence related sites of the same amino acids,in genetic relationship is in the same evolution branch and phylogenetic relationship of close,may has the same source.The results showed that the pathogen of this study was IBDV and had a strong virulence.