Classification of infectious bursal disease virus into genogroups

Abstract

Infectious bursal disease virus (IBDV) causes infectious bursal disease (IBD), an immunosuppressive disease of poultry. The current classification scheme of IBDV is confusing because it is based on antigenic types (variant and classical) as well as pathotypes. Many of the amino acid changes differentiating these various classifications are found in a hypervariable region of the capsid protein VP2 (hvVP2), the major host protective antigen. Data from this study were used to propose a new classification scheme for IBDV based solely on genogroups identified from phylogenetic analysis of the hvVP2 of strains worldwide. Seven major genogroups were identified, some of which are geographically restricted and others that have global dispersion, such as genogroup 1. Genogroup 2 viruses are predominately distributed in North America, while genogroup 3 viruses are most often identified on other continents. Additionally, we have identified a population of genogroup 3 vvIBDV isolates that have an amino acid change from alanine to threonine at position 222 while maintaining other residues conserved in this genogroup (I242, I256 and I294). A222T is an important mutation because amino acid 222 is located in the first of four surface loops of hvVP2. A similar shift from proline to threonine at 222 is believed to play a role in the significant antigenic change of the genogroup 2 IBDV strains, suggesting that antigenic drift may be occurring in genogroup 3, possibly in response to antigenic pressure from vaccination.Electronic supplementary materialThe online version of this article (doi:10.1007/s00705-017-3500-4) contains supplementary material, which is available to authorized users.

Revisiting the genetic diversity of classical swine fever virus: A proposal for new genotyping and subgenotyping schemes of classification

“…Similar approaches have been accomplished for other viral agents. Thus, the growing number of sequences for infectious bursal disease virus (IBDV) and the use of phylogenetic methodologies have enabled a new classification of this viral agent into seven genogroups, updating the previous classification which only recognized three groups (Michel & Jackwood, ). Likewise, for porcine circovirus type 2 (PCV2), a new genotype has been added to the previous taxonomic classification, after the analysis of approximately 3,300 new sequences of the complete genome of this virus (Franzo, Cortey, Segales, Hughes, & Drigo, ), which were submitted to GenBank database after the first taxonomical classification for PCV2 had been accomplished (Grau‐Roma et al., ).…”

Origin and global spreading of an ancestral lineage of the infectious bursal disease virus

“…The IBDV genome evolves rapidly via mutation, and less commonly by reassortment of both genome segments and recombination (He, Ma, Wang, Li, & Ding, ; Le Nouën et al, ; Pikuła, Lisowska, Jasik, & Śmietanka, ; Soubies et al, ). The action of these mechanisms has led to the emergence of a great deal of genetic variability, as evidenced by the existence of diverse evolutionary lineages in the viral populations (Michel & Jackwood, ).…”

Comparative in vivo pathogenicity study of an ITA genotype isolate (G6) of infectious bursal disease virus

“…In 2011, a new genotype of IBDV, named ITA, was detected in Italian broilers vaccinated with live IBDV vaccines (Lupini et al, 2016). Full genome characterization confirmed ITA to be a genetically different IBDV (Felice et al, 2017) and a recently proposed classification for IBDV into genogroups placed the ITA genotype into genogroup 6, together with a few other strains detected in Saudi Arabia and Russia (Michel & Jackwood, 2017). The currently available epidemiological and clinical data regarding strains of IBDV of the ITA genotype do not allow for a precise definition of their degree of pathogenicity, since the viruses have been detected in IBDVvaccinated broilers, sometimes with poor performance.…”