Molecular epidemiology studies on partial sequences of both genome segments reveal that reassortant infectious bursal disease viruses were dominantly prevalent in southern China during 2000-2012.

A molecular epidemiology study of infectious bursal disease viruses (IBDVs) isolated from seven provinces in southern China during the years 2000-2012 was performed based on partial sequences of genome segments A and B, namely the hypervariable region of the A-VP2 gene (A-vVP2) and the b fragment of VP1 gene (B-VP1b) from a total of 91 field isolates. Sequence analysis based on vVP2 revealed that 72 out of 91 isolates had the same characteristic amino acid (aa) sequences as vvIBDV. The mutation of D212N in A-vVP2 has become prevalent in the recent isolates.

Molecular epidemiology of infectious bursal disease viruses isolated from Southern China during the years 2000-2010.

We performed a molecular epidemiology study of infectious bursal disease virus (IBDV) from six provinces in southern China by analyzing IBDVs isolated during the years 2000-2010. Sequence analysis of hypervariable regions of the VP2 gene (vVP2) in the genome of these isolates revealed that the majority of these viruses (45/59) were characterized as vv (very virulent) IBDV genotype, 12 out of 59 isolates were avirulent IBDV genotype and two from Guangxi were intermediate IBDV genotype. Phylogenetic analysis revealed that 45 vvIBDV genotype isolates have divided into five groups, all displaying strong divergence from the currently used vaccine strains.

[Molecular epidemiology of infectious bursal disease virus in Guangxi during the period of 2000 to 2007].

Tissue samples of Fabricius' bursa collected from Nanning, Yulin, Beihai and Wuzhou in the provinces of Guangxi in China during the years of 2000-2007, were detected by a established reverse transcriptase polymerase chain reaction (RT-PCR) technique for IBDV. Viral isolation was performed on the positive samples by chicken embryo inoculation via chorio-allantoic membrane (CAM). Results showed that 27 isolates of IBDV were obtained.