Three non-vvIBDV strains detected in two broiler flocks were sequenced and compared to IBDV reference and Italian strains. The flocks, which belonged to two intensive farms located in Northern Italy, were vaccinated against IBDV and experienced recurrent bacterial infections and poor performances. Nucleotide sequence analysis of a 406bp-fragment of the genome, coding for the hypervariable region of VP2, revealed a homology of 100% between two of the strains and of 99% between them and the third one. Predicted amino acid sequences of the three strains were identical. When compared to classical, attenuated, very virulent and variant reference strains, as well as to Italian strains, they revealed to belong to a separate cluster. They showed a maximum degree of nucleotide and amino acid identity (95% and 95,6%, respectively) with only one IBDV strain, among those whose sequences are available in GenBank. At the amino acid level, the homology between the analyzed strains and published Italian strains ranged from 88% to 91%. Amino acid substitutions were observed in two of the hydrophilic peaks of VP2. Further studies are needed to evaluate the pathogenicity of these peculiar strains, their circulation in commercial broiler farms and the extent of protection offered against them by commercial IBDV vaccines.
Bonci M., Giovanardi D., Pesente P., Morandini E., Lupini C., Cecchinato M., et al. (2013). Caratterizzazione molecolare di ceppi del virus della Bursite Infettiva isolati recentemente in Italia.. Parma : La Ducale srl.
Caratterizzazione molecolare di ceppi del virus della Bursite Infettiva isolati recentemente in Italia.
BONCI, MICHELA;GIOVANARDI, DAVIDE;LUPINI, CATERINA;CECCHINATO, MATTIA;CATELLI, ELENA
2013
Abstract
Three non-vvIBDV strains detected in two broiler flocks were sequenced and compared to IBDV reference and Italian strains. The flocks, which belonged to two intensive farms located in Northern Italy, were vaccinated against IBDV and experienced recurrent bacterial infections and poor performances. Nucleotide sequence analysis of a 406bp-fragment of the genome, coding for the hypervariable region of VP2, revealed a homology of 100% between two of the strains and of 99% between them and the third one. Predicted amino acid sequences of the three strains were identical. When compared to classical, attenuated, very virulent and variant reference strains, as well as to Italian strains, they revealed to belong to a separate cluster. They showed a maximum degree of nucleotide and amino acid identity (95% and 95,6%, respectively) with only one IBDV strain, among those whose sequences are available in GenBank. At the amino acid level, the homology between the analyzed strains and published Italian strains ranged from 88% to 91%. Amino acid substitutions were observed in two of the hydrophilic peaks of VP2. Further studies are needed to evaluate the pathogenicity of these peculiar strains, their circulation in commercial broiler farms and the extent of protection offered against them by commercial IBDV vaccines.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
