{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,8]],"date-time":"2026-08-08T04:42:56Z","timestamp":1786164176415,"version":"build-2736575974"},"reference-count":23,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,8,8]],"date-time":"2026-08-08T00:00:00Z","timestamp":1786147200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,8,8]],"date-time":"2026-08-08T00:00:00Z","timestamp":1786147200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"name":"National Research Centre Egypt"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Sci Rep"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Infectious bursal disease virus (IBDV) causes severe immunosuppression diseases in poultry, resulting in substantial economic losses for the global poultry industry. This study aimed to characterize circulating IBDV strains in Egyptian chicken flocks and assess their potential impact on poultry health and production. We conducted a passive surveillance study by collecting bursal samples from a total of 30 flocks, including commercial broilers, layers, and Baladi chickens, across nine Egyptian governorates in 2025. These flocks exhibited clinical signs of depression, along with kidney and bursal lesions indicative of IBDV infection. Pooled bursal homogenates were tested using RT-PCR with VP2-specific primers, revealing that 20 flocks (66.6%) tested positive for IBDV. Field and vaccine strains were distinguished by phylogenetic clustering of the VP2 hypervariable region (HVR) sequences against reference vaccine strains (D78, Winterfield 228, VAXXITEK), strains that cluster closely with reference vaccine strains are classified as vaccine-origin, whereas field strains are distinct branches indicate circulating wild-type or vvIBDV. Ten representative positive samples were inoculated in specific pathogen-free embryonated chicken eggs (SPF-ECE). The inoculated embryos exhibited haemorrhage, skull swelling, and liver necrosis with a pale-yellow appearance, along with congestion and thickening of the chorioallantoic membrane (CAM). Phylogenetic analysis of the partial VP2 gene classified the isolates according to the unified genogroup nomenclature: the majority of isolates belonged to the A3 (vvIBDV) genogroup, while one isolate clustered within the A2d (nVarIBDV) genogroup. These findings highlight the co-circulation of both virulent and variant IBDV strains in Egyptian chicken flocks, complicating disease control and demanding a continued surveillance and periodic re-evaluation of vaccination programs.<\/jats:p>","DOI":"10.1038\/s41598-026-65194-0","type":"journal-article","created":{"date-parts":[[2026,8,8]],"date-time":"2026-08-08T03:45:38Z","timestamp":1786160738000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Passive surveillance of infectious bursal disease virus circulating in Egyptian chicken flocks in 2025"],"prefix":"10.1038","volume":"16","author":[{"given":"Amr H.","family":"Abd El-Fatah","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bouran","family":"Salama","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mariam O.","family":"Elnahhas","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Noura M.","family":"Abo Shama","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7556-9398","authenticated-orcid":false,"given":"Mahmoud","family":"Shehata","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,8,8]]},"reference":[{"key":"65194_CR1","doi-asserted-by":"publisher","first-page":"1330576","DOI":"10.3389\/fimmu.2023.1330576","volume":"14","author":"T Zhang","year":"2023","unstructured":"Zhang, T., Wang, S., Liu, Y., Qi, X. & Gao, Y. Advances on adaptive immune responses affected by infectious bursal disease virus in chicken. Front. Immunol. 14, 1330576. https:\/\/doi.org\/10.3389\/fimmu.2023.1330576 (2023).","journal-title":"Front. Immunol."},{"key":"65194_CR2","doi-asserted-by":"publisher","first-page":"190","DOI":"10.1080\/03079457.2021.1873245","volume":"50","author":"MR Islam","year":"2021","unstructured":"Islam, M. R. et al. A unified genotypic classification of infectious bursal disease virus based on both genome segments. Avian Pathol. 50, 190\u2013206. https:\/\/doi.org\/10.1080\/03079457.2021.1873245 (2021).","journal-title":"Avian Pathol."},{"key":"65194_CR3","doi-asserted-by":"publisher","first-page":"105195","DOI":"10.1016\/j.psj.2025.105195","volume":"104","author":"H Yu","year":"2025","unstructured":"Yu, H. et al. Epidemiological characteristics of infectious bursal disease virus (IBDV) in China from 2023 to 2024: Mutated very virulent IBDV (mvvIBDV) is associated with atypical IBD. Poult. Sci. 104, 105195. https:\/\/doi.org\/10.1016\/j.psj.2025.105195 (2025).","journal-title":"Poult. Sci."},{"key":"65194_CR4","doi-asserted-by":"publisher","first-page":"8255","DOI":"10.3390\/ijms24098255","volume":"24","author":"H Gao","year":"2023","unstructured":"Gao, H., Wang, Y., Gao, L. & Zheng, S. J. Genetic insight into the interaction of IBDV with host\u2014a clue to the development of novel IBDV vaccines. Int. J. Mol. Sci. 24, 8255 (2023).","journal-title":"Int. J. Mol. Sci."},{"key":"65194_CR5","doi-asserted-by":"publisher","first-page":"867","DOI":"10.3390\/vaccines11040867","volume":"11","author":"I Nwagbo","year":"2023","unstructured":"Nwagbo, I. et al. Genomic analysis of infectious bursal disease virus in Nigeria: Identification of unique mutations of yet unknown biological functions in both segments A and B. Vaccines 11, 867 (2023).","journal-title":"Vaccines"},{"key":"65194_CR6","doi-asserted-by":"publisher","first-page":"8182160","DOI":"10.1155\/2016\/8182160","volume":"2016","author":"HB Aliyu","year":"2016","unstructured":"Aliyu, H. B., Sa\u2019idu, L., Jamilu, A., Andamin, A. D. & Akpavie, S. O. Outbreaks of virulent infectious bursal disease in flocks of battery cage brooding system of commercial chickens. J. Veterinary Med. 2016, 8182160. https:\/\/doi.org\/10.1155\/2016\/8182160 (2016).","journal-title":"J. Veterinary Med."},{"key":"65194_CR7","doi-asserted-by":"publisher","first-page":"2388","DOI":"10.3390\/v15122388","volume":"15","author":"M Legnardi","year":"2023","unstructured":"Legnardi, M. et al. First detection and molecular characterization of novel variant infectious bursal disease virus (genotype A2dB1b) in Egypt. Viruses 15, 2388 (2023).","journal-title":"Viruses"},{"key":"65194_CR8","unstructured":"OIE. Infectious bursal disease (Gumboro disease). In Chapter 2.3.12. OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals 1\u201321 (Paris, 2016)."},{"key":"65194_CR9","doi-asserted-by":"publisher","first-page":"3022","DOI":"10.1093\/molbev\/msab120","volume":"38","author":"K Tamura","year":"2021","unstructured":"Tamura, K., Stecher, G. & Kumar, S. MEGA11: Molecular evolutionary genetics analysis version 11. Mol. Biol. Evol. 38, 3022\u20133027 (2021).","journal-title":"Mol. Biol. Evol."},{"key":"65194_CR10","doi-asserted-by":"publisher","first-page":"12827","DOI":"10.1128\/JVI.01501-07","volume":"81","author":"T Letzel","year":"2007","unstructured":"Letzel, T. et al. Molecular and structural bases for the antigenicity of VP2 of infectious bursal disease virus. J. Virol. 81, 12827\u201312835 (2007).","journal-title":"J. Virol."},{"key":"65194_CR11","doi-asserted-by":"publisher","first-page":"283","DOI":"10.21608\/bvmj.2015.32516","volume":"28","author":"GF El-Bagoury","year":"2015","unstructured":"El-Bagoury, G. F., El-Nahas, E. M. & El-Habbaa, A. S. Isolation and molecular characterization of IBDV from Qualubyia governorate, Egypt, 2015. Benha Veterinary Med. J. 28, 283\u2013294. https:\/\/doi.org\/10.21608\/bvmj.2015.32516 (2015).","journal-title":"Benha Veterinary Med. J."},{"key":"65194_CR12","doi-asserted-by":"publisher","first-page":"46","DOI":"10.1016\/j.ijvsm.2014.02.004","volume":"2","author":"SA Mawgod","year":"2014","unstructured":"Mawgod, S. A., Arafa, A. S. & Hussein, H. A. Molecular genotyping of the infectious bursal disease virus (IBDV) isolated from broiler flocks in Egypt. Int. J. Veterinary Sci. Med. 2, 46\u201352. https:\/\/doi.org\/10.1016\/j.ijvsm.2014.02.004 (2014).","journal-title":"Int. J. Veterinary Sci. Med."},{"key":"65194_CR13","doi-asserted-by":"publisher","first-page":"133","DOI":"10.1080\/03079457.2012.661403","volume":"41","author":"H M\u00fcller","year":"2012","unstructured":"M\u00fcller, H., Mundt, E., Eterradossi, N. & Islam, M. R. Current status of vaccines against infectious bursal disease. Avian Pathol. 41, 133\u2013139 (2012).","journal-title":"Avian Pathol."},{"key":"65194_CR14","doi-asserted-by":"publisher","first-page":"292","DOI":"10.1080\/00439339.2020.1716652","volume":"76","author":"O Orakpoghenor","year":"2020","unstructured":"Orakpoghenor, O., Oladele, S. B. & Abdu, P. A. Infectious bursal disease: Transmission, pathogenesis, pathology and control-an overview. World\u2019s Poult. Sci. J. 76, 292\u2013303 (2020).","journal-title":"World\u2019s Poult. Sci. J."},{"key":"65194_CR15","doi-asserted-by":"publisher","DOI":"10.3390\/v15010130","author":"AS Asfor","year":"2022","unstructured":"Asfor, A. S. et al. Modeling infectious bursal disease virus (IBDV) antigenic drift in vitro. Viruses. https:\/\/doi.org\/10.3390\/v15010130 (2022).","journal-title":"Viruses"},{"key":"65194_CR16","doi-asserted-by":"publisher","first-page":"225","DOI":"10.1016\/j.antiviral.2009.09.006","volume":"84","author":"X Qi","year":"2009","unstructured":"Qi, X. et al. Naturally occurring mutations at residues 253 and 284 in VP2 contribute to the cell tropism and virulence of very virulent infectious bursal disease virus. Antiviral Res. 84, 225\u2013233. https:\/\/doi.org\/10.1016\/j.antiviral.2009.09.006 (2009).","journal-title":"Antiviral Res."},{"key":"65194_CR17","doi-asserted-by":"publisher","first-page":"e639","DOI":"10.1002\/cpz1.639","volume":"3","author":"V Reddy","year":"2023","unstructured":"Reddy, V., Nazki, S., Asfor, A. & Broadbent, A. J. An infectious bursal disease virus (IBDV) reverse genetics rescue system and neutralization assay in chicken B cells. Curr. Protoc. 3, e639. https:\/\/doi.org\/10.1002\/cpz1.639 (2023).","journal-title":"Curr. 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Sci. 103, 103623. https:\/\/doi.org\/10.1016\/j.psj.2024.103623 (2024).","journal-title":"Poult. Sci."},{"key":"65194_CR23","doi-asserted-by":"crossref","unstructured":"Abd El-Fatah, A. H. et al. Molecular characterization of circulating infectious bursal disease viruses in chickens from different Egyptian governorates during 2023. Virol. J. 21, 312. https:\/\/doi:10.1186\/s12985-024-02559-9 (2024).","DOI":"10.1186\/s12985-024-02559-9"}],"container-title":["Scientific Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-65194-0","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-65194-0.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-65194-0.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,8]],"date-time":"2026-08-08T04:06:44Z","timestamp":1786162004000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-65194-0"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,8]]},"references-count":23,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,12]]}},"alternative-id":["65194"],"URL":"https:\/\/doi.org\/10.1038\/s41598-026-65194-0","relation":{},"ISSN":["2045-2322"],"issn-type":[{"value":"2045-2322","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,8]]},"assertion":[{"value":"24 February 2026","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"29 July 2026","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"8 August 2026","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"The authors declare no competing interests.","order":1,"name":"Ethics","label":"Competing interests","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"All experimental procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee of EVA Pharma for Pharmaceutical Industries, Egypt (Approval No. EVA\/003\/2025). All methods were performed in accordance with the relevant institutional guidelines and regulations for animal care and use. Prior to sample collection, oral permission was obtained from the owners of the poultry farms.","order":2,"name":"Ethics","label":"Ethical approval and consent to participate","group":{"name":"EthicsHeading","label":"Declarations"}}],"article-number":"24540"}}