Emergence of the novel infectious bursal disease virus variant in vaccinated poultry flocks in Egypt

• DOI: 10.1080/03079457.2024.2348513
• Publication Date: 2024-05-24T07:43:20Z
• Authors: Momtaz A. Shahein; Hesham A. Sultan; Ali Zanaty; Amany Adel; Zienab Mosaad; Dalia Said; Ahmed Erfan; Mohamed Samy; Abdullah Selim; Karim Selim; Mahmoud M. Naguib; Heba Hassan; Osama El Shazly; Zeinab A. El-badiea; Mahmoud K. Moawad; Abdelhafez Samir; Mohamed El Shahaby; Eman Farghaly; Samah Eid; Mohamed N. Abdelaziz; Mohamed M. Hamoud; Osama Mehana; Naglaa M. Hagag; Ahmed Samy
• Keywords: Infectious bursal disease; Flock; Newcastle Disease

Since the detection of antigenically atypical very virulent Infectious bursal disease viruses (vvIBDV) in Egypt 1999, country has been experiencing recurrent outbreaks with high mortality rates and typical gross lesions associated vvIBDV. However, a significant change occurred 2023, marked by notable increase reported subclinical IBDV cases. To evaluate field situation, samples from 21 farms 2023 18 2021 2022, all which had experienced IBD based on clinical diagnosis, were collected, subjected to VP2-HVR sequencing. Phylogenetic analysis revealed that collected 2022 clustered classical strains In one sample Egyptian vvIBDV, another IBDV, rest novel variant (nVarIBDV) circulating China. The alignment deduced amino acid sequences for VP2 showed classic identical Winterfield or Lukert strains, while vvIBDV exhibited two out three residues found namely Y220F G254S, but not A321T. Meanwhile, nVarIBDV. variants mutation at position 321 (321V), represents most exposed part capsid is known have massive impact antigenicity, except 318G instead. This report highlights emergence new Egypt, Chinese variants, spreading subclinically broiler across wide geographic area.