Frontiers in Veterinary Science (Feb 2022)

Infectious Bronchitis Virus Infection Increases Pathogenicity of H9N2 Avian Influenza Virus by Inducing Severe Inflammatory Response

  • Lingchen Kong,
  • Lingchen Kong,
  • Lingchen Kong,
  • Lingchen Kong,
  • Renrong You,
  • Renrong You,
  • Renrong You,
  • Renrong You,
  • Dianchen Zhang,
  • Dianchen Zhang,
  • Dianchen Zhang,
  • Dianchen Zhang,
  • Qingli Yuan,
  • Qingli Yuan,
  • Qingli Yuan,
  • Qingli Yuan,
  • Bin Xiang,
  • Bin Xiang,
  • Bin Xiang,
  • Bin Xiang,
  • Jianpeng Liang,
  • Jianpeng Liang,
  • Jianpeng Liang,
  • Jianpeng Liang,
  • Qiuyan Lin,
  • Qiuyan Lin,
  • Qiuyan Lin,
  • Qiuyan Lin,
  • Chan Ding,
  • Ming Liao,
  • Ming Liao,
  • Ming Liao,
  • Ming Liao,
  • Libin Chen,
  • Libin Chen,
  • Libin Chen,
  • Libin Chen,
  • Tao Ren,
  • Tao Ren,
  • Tao Ren,
  • Tao Ren

DOI
https://doi.org/10.3389/fvets.2021.824179
Journal volume & issue
Vol. 8

Abstract

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Infectious bronchitis virus (IBV) and H9N2 avian influenza virus (AIV) are frequently identified in chickens with respiratory disease. However, the role and mechanism of IBV and H9N2 AIV co-infection remain largely unknown. Specific-pathogen-free (SPF) chickens were inoculated with IBV 2 days before H9N2 virus inoculation (IBV/H9N2); with IBV and H9N2 virus simultaneously (IBV+H9N2); with H9N2 virus 2 days before IBV inoculation (H9N2/IBV); or with either IBV or H9N2 virus alone. Severe respiratory signs, pathological damage, and higher morbidity and mortality were observed in the co-infection groups compared with the IBV and H9N2 groups. In general, a higher virus load and a more intense inflammatory response were observed in the three co-infection groups, especially in the IBV/H9N2 group. The same results were observed in the transcriptome analysis of the trachea of the SPF chickens. Therefore, IBV might play a major role in the development of respiratory disease in chickens, and secondary infection with H9N2 virus further enhances the pathogenicity by inducing a severe inflammatory response. These findings may provide a reference for the prevention and control of IBV and H9N2 AIV in the poultry industry and provide insight into the molecular mechanisms of IBV and H9N2 AIV co-infection in chickens.

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