Molecular studies of the Brazilian infectious bronchitis virus isolates

Abstract

Avian infectious bronchitis virus (IBV) isolates have been widely characterized by reverse transcription followed by polymerase chain reaction and DNA sequencing. In present study, these techniques were applied to three viral genomic regions comprising the complete and/or a partial S1 segment, S2 and nucleocapsid genes. DNA sequences from viral isolates obtained from 1972 to 1989 and from 2006 to 2008 were compared. High similarity (>90%) was observed among some of the genomic segments, including S1 hypervariable region, which could suggest a common origin or ancestry. DNA sequences from S2 and N protein genes obtained from different infected tissues of the same flock were analyzed, and a clear segregation between respiratory and intestinal tract was observed. Therefore, these data suggest cocirculation of more than one viral strain in the same flock. 57.1% of DNA sequences from the S1 complete segment samples, 53.3% from the S2 fragment and 62.5% from the partial N gene were found to be different from analyzed sequences from reference strains leading to the conclusion that parte of viral isolates included in this study may be considered region specific. Considering the simultaneous analysis of the three genes, a large IBV genetic profile was observed in both old and recent isolates groups. However, most prominent diversity between viral isolates was obtained in the period from 1972 and 1989, showing the presence of a large number of variants in the state of Minas Gerais before the official approval of vaccination (1980).

<n>Genetic diversity of avian coronavirus infectious bronchitis detected from commercial poultry in Brazil</n>

“…Most of the isolates from this study were identified as belonging to the BR-I genotype (CHACON et al, 2011). This genotype appeared to be the most disseminated and predominant IBV variant causing disease in poultry, because our results and other epidemiological studies detected this genotype in different Brazilian regions (ABREU et al, 2010;FELIPPE et al, 2010) from birds with respiratory, renal, enteric or reproductive signs and mortality. Additionally only the isolate USP 555-6 (detected in tracheal tissue) clustered together with isolates belonging to the BR-II genotype (Figure 2).…”

Characterization of novel, pathogenic field strains of infectious bronchitis virus (IBV) in poultry in Trinidad and Tobago

“…Phylogenetic analysis using the spike glycoprotein S1 coding region is useful for the differentiation and classification of IBV strains and lineages, and for predicting levels of cross‐protective immunity (Bayry et al., 2005; Valastro et al., 2016). Multiple studies carried out in Latin America have identified IBV as causing disease on poultry farms across the region, in both vaccinated and unvaccinated settings (Abreu et al., 2010; Jackwood, 2012; Villarreal et al., 2010). Further analysis of novel strains identified in Brazil, Argentina and Uruguay revealed distinctive South American lineages.…”

“…The scale bar represents the number of nucleotide substitutions per site, and the tree is mid-point rooted for sake of clarity only [Colour figure can be viewed at wileyonlinelibrary.com] Phylogenetic analysis using the spike glycoprotein S1 coding region is useful for the differentiation and classification of IBV strains and lineages, and for predicting levels of cross-protective immunity (Bayry et al, 2005;Valastro et al, 2016). Multiple studies carried out in Latin America have identified IBV as causing disease on poultry farms across the region, in both vaccinated and unvaccinated settings (Abreu et al, 2010;Jackwood, 2012;Villarreal et al, 2010).…”

“…However, over time, new variants of IBV, some with increased virulence, such as the California‐type, Pennsylvania and Georgia strains, have emerged in the United States (Jackwood, 2012; Jackwood, Hilt, Sellers, Williams, & Lasher, 2010; Lee, Hilt, & Jackwood, 2001; Thor, Hilt, Kissinger, Paterson, & Jackwood, 2011). IBV has also been reported to be circulating in Brazil, Mexico, Chile and Colombia (Abreu et al., 2010; Chacon et al., 2011; Jackwood, 2012; Villarreal et al., 2010). Brazil has described the presence of unique variants of IBV, in addition to variants similar to the European 793B type and Mass type (Villarreal et al., 2010).…”