Characterisation of an Indonesian very virulent strain of infectious bursal disease virus

Abstract

An Indonesian very virulent (vv) strain of infectious bursal disease virus (IBDV), designated Tasik94, was characterised both in vivo and at the molecular level. Inoculation of Tasik94 into 5-week-old specific-pathogen-free (SPF) chickens resulted in 100% morbidity and 45% mortality. The complete nucleotide and predicted amino acid sequences of genomic segments A and B were determined. Across each of the three deduced open reading frames (ORFs), Tasik94 shared the greatest nucleotide homology to Dutch vv strain D6948. Phylogenetic analyses were performed using 15 full-length polyprotein sequences and a total of 105 VP2 hypervariable region sequences from geographically and pathogenically diverse strains. In each case, Tasik94 grouped closely with vv strains, particularly those from Europe. The deduced VP1, VP2, VP3, VP4 and VP5 protein sequences of Tasik94 were aligned with those from published strains and putative virulence determinants were identified in VP2, VP3 and VP4. Alignment of additional protein sequences across the VP2 hypervariable region confirmed that residues Ile[242], Ile[256] and Ile[294] were highly-conserved amongst vv strains, and may account for their enhanced virulence.

Genetic characterization of South American infectious bursal disease virus reveals the existence of a distinct worldwide-spread genetic lineage

“…The dIBDVs share relevant amino acids markers (222S, 256V, 294L and 299N/S) with both vvIBDV and nonvvIBDV strains. The 222S residue was already reported in the classic Lukert strain, in few vvIBDVs, and in a Belgian isolate that was considered a European variant with a different antigenic profile produced by the P222S change (Rudd et al, 2002;Jackwood & Sommer-Wagner, 2007;Letzel et al, 2007). The 256V and 294L residues are characteristic of the non-vvIBDVs, while the dIBDVs have a 299N, like most non-vvIBDVs, or 299S, as most vvIBDVs.…”

Extensive antigenic changes in an atypical isolate of very virulent infectious bursal disease virus and experimental clinical control of this virus with an antigenically classical live vaccine

“…The nt sequence of the 99323 isolate was mostly similar with that of reference vvIBDV strain 89163 (only nine nt positions differed, 98.0% nt identity). Four of these nt changes were silent mutations, hence the deduced aa sequence was also very similar to that of 89163 (Figure 1) and presented the four aa positions 222A, 256I, 284I and 299S, which have been found in every vvIBDV so far characterized, with the two exceptions of an early IBDV strain from Ivory Coast that has not been reisolated since 1988 (Brown et al, 1994;Cao et al, 1998;To et al, 1999;Zierenberg et al, 2000) and of Indonesian strain Tasik94, which differs from typical vvIBDVs by lacking residue 222A (Rudd et al, 2002). However, the 99323 isolate also exhibited three non-silent nt changes, which encoded three aa changes that have not so far been found in any other vvIBDV-like viruses; namely, Y220 0/ F, G254 0/ S and A321 0/ T. These changes occurred in regions that are known to be important for antigenicity: VP2 major hydrophilic peak A (position 220), VP2 first minor hydrophilic peak (position 254) and VP2 second major hydrophilic peak (position 321) (Schnitzler et al, 1993;Vakharia et al, 1994;van den Berg et al, 1996).…”

Phylogeographic distribution of very virulent infectious bursal disease virus isolates in the Iberian Peninsula

“…Since the usage and availability of nucleic acid sequences have been extended in the veterinary field, numerous studies have characterized IBDV isolates all over the world (i.e., Brown et al, 1994;Etterradossi et al, 2000;Zierenberg et al, 2000;Liu et al, 2002;Rudd et al, 2002;Hernandez et al, 2006) …”

“…In the geographic design, two large areas that contained different regions of the Iberian Peninsula were considered: the Mediterranean region (Catalunya, València, lles Balears, Murcia, Andalucía) together with the northeastern region (Aragó n, Navarra, Rioja; M/E region); and the Atlantic and central-western regions (Portugal, Galicia, Castilla-la-Mancha, Castilla-Leó n; A/W region). A matrix of nucleotide divergence between regions was calculated using MEGA 4 (Tamura et al, 2007) and the gamma TamuraÁNei model. This distance matrix of nucleotide divergence was used to perform principal coordinate (PCO) analysis using the PCO program (Anderson, 2003).…”

“…The first principal coordinate accounts for as much variability in the data as possible, and each following coordinate accounts for as much of the remaining variability as possible. Finally, a neighbour-joining tree including Iberian and world vvIBDV nucleotide sequences was constructed using MEGA 4 (Tamura et al, 2007) and the gamma TamuraÁNei model. The confidence of internal branches was estimated by means of 1000 bootstrap replicates.…”