Molecular characterization of circulating infectious bursal disease viruses in chickens from different Egyptian governorates during 2023.

Autor: Abd El-Fatah AH; Egyptian Company for Biological & Pharmaceutical Industries (Vaccine Valley), 6th October City, Giza, 12511, Egypt., Ayman D; Egyptian Company for Biological & Pharmaceutical Industries (Vaccine Valley), 6th October City, Giza, 12511, Egypt., Samir M; Laboratory for Veterinary Quality Control On Poultry Production, Animal Health Research Institute, Agricultural Research Center, Dokki, Giza, 12618, Egypt., Eid S; Egyptian Company for Biological & Pharmaceutical Industries (Vaccine Valley), 6th October City, Giza, 12511, Egypt., Elgamal M; Department of Virology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt., El-Sanousi AA; Department of Virology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt., Ibrahim M; Department of Birds and Rabbit Medicine, Faculty of Veterinary Medicine, University of Sadat City, Menoufiya, 32958, Egypt. mahmoud.jameel@vet.usc.edu.eg., AlKhazindar M; Botany and Microbiology Department, Faculty of Science, Cairo University, Giza, Egypt., Ali MM; Biotechnology Department, Faculty of Science, Cairo University, Giza, Egypt., Afify A; Biotechnology Department, Faculty of Science, Cairo University, Giza, Egypt.
Jazyk: angličtina
Zdroj: Virology journal [Virol J] 2024 Nov 30; Vol. 21 (1), pp. 312. Date of Electronic Publication: 2024 Nov 30.
DOI: 10.1186/s12985-024-02559-9
Abstrakt: Infectious bursal disease virus (IBDV) induces severe immunosuppression in chickens, leading to significant economic losses in the global poultry industry. This study investigated 52 chicken flocks, including commercial broilers, layers, and baladi, from various Egyptian governorates in 2023. These flocks exhibited symptoms of depression, along with kidney and bursa lesions, indicative of IBDV infection. Pooled Bursal homogenates were tested using RT-PCR with VP2-specific primers, revealing that 20 flocks tested positive for IBDV. Six representative samples were selected from 20 positive flocks for isolation in embryonated chicken eggs. The embryonic lesions observed included haemorrhage, skull swelling, and liver necrosis with a pale-yellow appearance, in addition to congestion and thickening in the chorioallantoic membrane (CAM). Partial amplification of the VP2 gene from the harvested embryo suspensions of the six IBDV isolates was performed for sequencing. Phylogenetic analysis of the sequences revealed that five IBDV isolates (VV4, VV5, VV6, VV10, and VV16) belonged to the very virulent strain group A3 cluster, whereas one isolate (VV2) clustered with Chinese Variant strains in the A2d group. Sequence analysis of the hypervariable region (HVR) of VP2 compared to that of Egypt-USC-IBD-1-2019 and vvIBDV/Beh21/Egypt/18 highly virulent IBDV strains revealed several amino acid mutations. The VP2 HVR of all isolates maintained the serine-rich heptapeptide sequence SWSASGS, which is adjacent to the major hydrophilic peak B and serves as a virulence marker. Histopathological examination revealed that bursae from chickens infected with vvIBDV exhibited marked interlobular oedema and lymphoid depletion. In contrast, bursae from chickens infected with Variant IBDV showed massive lymphoid depletion, with hyperplasia of the bursal capsule. These findings highlight the circulation of both virulent and Variant IBDV strains in Egyptian chicken flocks, complicating disease control. Consequently, there is a need to update vaccination programs and vaccine strains for IBDV in Egypt.
Competing Interests: Declarations. Ethical approval: Ethical approval for this study was given by the Institutional Animal Care and Use Committee under University of Sadat City No. VUSC-038–1-23. Ethical consideration: The authors confirm that all authors have reviewed and submitted the manuscript to this journal for the first time. Competing  interests: The authors declare no competing interests.
(© 2024. The Author(s).)
Databáze: MEDLINE
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