The VP2 variable region of African and German isolates of infectious bursal disease virus: comparison with very virulent, "classical" virulent, and attenuated tissue culture-adapted strains

Abstract

11 African and two German IBDV strains isolated in the mid '80s from field outbreaks in vaccinated and unvaccinated chicken flocks displayed features of very virulent (vv) IBDV strains. The sequence data of the VP2 variable region and phylogenetic analysis confirm that these strains can be grouped within vv IBDV strains which appeared at the same time on the three continents Africa, Asia, and Europe. Strain Cu-1wt, responsible for severe IBD outbreaks in Germany 13 years earlier, showed some relatedness to these strains, but also significant differences at the genomic level, even though this strain has also features of the vv IBDV strains.

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).…”

Restriction fragment length polymorphism analysis of the VP2 gene of Australian strains of infectious bursal disease virus

“…All IBDV strains are immunosuppressive; however, strains can be classified according to differences in virulence and antigenicity (van den Berg, 2000). Classical IBDV strains have worldwide distribution, with some strains capable of causing low mortalities.…”

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

“…Many molecular studies in Gumboro have been restricted to the regional level: Spain (Pagès-Mante et al, 1991;Majó et al, 2002;Dolz et al, 2005), Uruguay (Hernandez et al, 2006), Croatia (Lojkic et al, 2008), People's Republic of China (Liu et al, 2002) or Brazil (Fernandes et al, 2009). In contrast, few studies seek for evolutive relationships on a global scale among vvIBDV strains Zierenberg et al, 2000). In order to determine the population structure present among vvIBDV strains, this study adopted two approaches: a general comparison among most (n065) of the vvIBDV strains described worldwide, and a regional longitudinal analysis including 102 vvIBDV Iberian strains isolated during a 20-year period.…”

“…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) …”