Emergence and molecular characterization of the avian infectious bronchitis virus GI‐23 in commercial broiler farms from South America

• Published in: Transboundary and emerging diseases Vol. 69; no. 6; pp. 3167 - 3172
• Main Authors: Ikuta, Nilo, Fonseca, André Salvador Kazantzi, Fernando, Filipe Santos, Filho, Tobias Fernandes, Martins, Nelson Rodrigo da Silva, Lunge, Vagner Ricardo
• Format: Journal Article
• Language: English
• Published: Germany Hindawi Limited 01.11.2022
• Subjects: 5' Untranslated Regions; Amino acid sequence; Amino acids; Animals; Avian infectious bronchitis; Brazil; Brazil - epidemiology; Bronchitis; Chickens; Coronavirus Infections - epidemiology; Coronavirus Infections - veterinary; Economic impact; Epidemiology; Farms; Gene sequencing; Genotype; Genotyping; GI‐23 lineage; IBV; Infectious bronchitis virus - genetics; molecular diversity; phylogenetic; Phylogeny; Poultry; Poultry Diseases - epidemiology; Proteins; S1 gene; Sequence analysis; Spike protein; Viruses; Brazil; South America; Brazil; GI-23 lineage; molecular diversity; phylogenetic; IBV
• ISSN: 1865-1674; 1865-1682
• DOI: 10.1111/tbed.14724

Avian infectious bronchitis virus (IBV) is the etiological agent of a highly contagious disease in the poultry industry. The spike protein (S1 subunit) is responsible for the molecular diversity of the virus and many genetic types, and lineages are described worldwide. IBV genetic type I—strain 23 (GI‐23) has spread across different continents (including Asia, Europe and Africa), causing multiple outbreaks and severe economic losses throughout the poultry industry in the last decade. The present study aimed to report the emergence and molecular characterization of GI‐23 in South Brazil, being detected for the first time in South America. Eighty‐two broiler flocks presenting clinical suspicion of infectious bronchitis were selected for this study. Tracheal, renal and intestinal samples were collected for IBV detection and genotyping. A total of 57 flocks were positive for IBV by generic RT‐qPCR targeting 5' untranslated region and 31 also tested positive for GI‐11 by a specific RT‐qPCR targeting S1 gene for this lineage. The remaining 26 IBV‐positive samples were genotyped by partial and one by complete S1 gene/protein sequencing. Phylogenetic analysis demonstrated that all of them clustered into a specific branch of the GI‐23. S1 protein sequence analysis evidenced that all Brazilian GI‐23 IBVs had the two characteristic amino acid substitutions A93T and S/H118P/L, but other changes were also observed, such as S37F (n = 21; 81%), G117S (n = 17, 65%), P122S (n = 16; 61%) and W71R (n = 9; 35%). This study brings new insights into the epidemiology of the IBV GI‐23 in the world, highlighting its emergence and molecular characteristics in Brazil, South America.