Pathogenicity, immunogenicity, and multi-organ tissue tropism of a novel variant infectious bursal disease virus in specific pathogen-free chickens

Background and Aim: Novel variant infectious bursal disease virus (nVarlBDV) occurs worldwide, causing significant morbidity and bursal atrophy in chickens, leading to immunosuppression and heavy economic losses. This study aimed to evaluate the pathogenicity, immunogenicity, and virus load of nVarl...

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Main Authors: Hair-Bejo, Mohd, Mazlan, Mazlina, Be, Tein Hock, Han, Chong Hao, Mohamed Sohaimi, Norfitriah, Ugwu, Chidozie Clifford
Format: Article
Language:en
Published: Veterinary World 2026
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Online Access:http://psasir.upm.edu.my/id/eprint/123788/1/123788.pdf
http://psasir.upm.edu.my/id/eprint/123788/
https://veterinaryworld.org/Vol.19/February-2026/10.php
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author Hair-Bejo, Mohd
Mazlan, Mazlina
Be, Tein Hock
Han, Chong Hao
Mohamed Sohaimi, Norfitriah
Ugwu, Chidozie Clifford
author_facet Hair-Bejo, Mohd
Mazlan, Mazlina
Be, Tein Hock
Han, Chong Hao
Mohamed Sohaimi, Norfitriah
Ugwu, Chidozie Clifford
author_sort Hair-Bejo, Mohd
building UPM Library
collection Institutional Repository
content_provider Universiti Putra Malaysia
content_source UPM Institutional Repository
continent Asia
country Malaysia
description Background and Aim: Novel variant infectious bursal disease virus (nVarlBDV) occurs worldwide, causing significant morbidity and bursal atrophy in chickens, leading to immunosuppression and heavy economic losses. This study aimed to evaluate the pathogenicity, immunogenicity, and virus load of nVarlBDV in organs of specific-pathogen-free (SPF) chickens. Materials and Methods: Sixty, 21-day-old SPF chickens were divided into Groups A and B. Birds in Group A were inoculated with 106.75 EID50/ mL of nVarlBDV (UPM1432/2019) while Group B served as a control. Four birds from Group B were sacrificed at 0 days post-inoculation (dpi). Four birds from each group were sacrificed at 1, 3, 5, 7, 10, 14, and 21 dpi. Clinical signs and serum samples were collected. Body, bursa, and spleen weights, and gross lesions were recorded. Bursa samples were collected for histological examination, while the bursa, spleen, caecal tonsils, thymus, and bone marrow were collected for the virus load determination. Data was analyzed using Student’s t-test at 95 Results: Watery diarrhea and ruffled feathers, bursal atrophy, yellowish stain, decreased folds, firm consistency of bursa, and splenomegaly were observed in Group A. Bursal follicles were atrophied with bursal lesion scores of 4 to 5. IBD antibody titer in Group A, ranging from 6921 -13869 ELISA units at 5-21 dpi, was significantly higher (p<0.05) than in Group B at all timepoints. The viral load was highest in the bursa and lowest in the bone marrow and was detected from 1-21 dpi in the bursa, spleen, caecal tonsil, and thymus, and up to 7 dpi in the bone marrow with a copy number ranging from 7.111 - 12.414 log10. Conclusion: The nVarlBDV was highly pathogenic, immunogenic, and highly infective in the organs of SPF chickens. It could cause immunosuppression in chickens, exposing them to secondary infections with resultant heavy economic losses, and this report of the detection of nVarlBDV in these organs up to 21 dpi is novel.
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spelling my.upm.eprints-1237882026-03-18T08:25:59Z http://psasir.upm.edu.my/id/eprint/123788/ Pathogenicity, immunogenicity, and multi-organ tissue tropism of a novel variant infectious bursal disease virus in specific pathogen-free chickens Hair-Bejo, Mohd Mazlan, Mazlina Be, Tein Hock Han, Chong Hao Mohamed Sohaimi, Norfitriah Ugwu, Chidozie Clifford Background and Aim: Novel variant infectious bursal disease virus (nVarlBDV) occurs worldwide, causing significant morbidity and bursal atrophy in chickens, leading to immunosuppression and heavy economic losses. This study aimed to evaluate the pathogenicity, immunogenicity, and virus load of nVarlBDV in organs of specific-pathogen-free (SPF) chickens. Materials and Methods: Sixty, 21-day-old SPF chickens were divided into Groups A and B. Birds in Group A were inoculated with 106.75 EID50/ mL of nVarlBDV (UPM1432/2019) while Group B served as a control. Four birds from Group B were sacrificed at 0 days post-inoculation (dpi). Four birds from each group were sacrificed at 1, 3, 5, 7, 10, 14, and 21 dpi. Clinical signs and serum samples were collected. Body, bursa, and spleen weights, and gross lesions were recorded. Bursa samples were collected for histological examination, while the bursa, spleen, caecal tonsils, thymus, and bone marrow were collected for the virus load determination. Data was analyzed using Student’s t-test at 95 Results: Watery diarrhea and ruffled feathers, bursal atrophy, yellowish stain, decreased folds, firm consistency of bursa, and splenomegaly were observed in Group A. Bursal follicles were atrophied with bursal lesion scores of 4 to 5. IBD antibody titer in Group A, ranging from 6921 -13869 ELISA units at 5-21 dpi, was significantly higher (p<0.05) than in Group B at all timepoints. The viral load was highest in the bursa and lowest in the bone marrow and was detected from 1-21 dpi in the bursa, spleen, caecal tonsil, and thymus, and up to 7 dpi in the bone marrow with a copy number ranging from 7.111 - 12.414 log10. Conclusion: The nVarlBDV was highly pathogenic, immunogenic, and highly infective in the organs of SPF chickens. It could cause immunosuppression in chickens, exposing them to secondary infections with resultant heavy economic losses, and this report of the detection of nVarlBDV in these organs up to 21 dpi is novel. Veterinary World 2026-02-17 Article PeerReviewed text en cc_by_4 http://psasir.upm.edu.my/id/eprint/123788/1/123788.pdf Hair-Bejo, Mohd and Mazlan, Mazlina and Be, Tein Hock and Han, Chong Hao and Mohamed Sohaimi, Norfitriah and Ugwu, Chidozie Clifford (2026) Pathogenicity, immunogenicity, and multi-organ tissue tropism of a novel variant infectious bursal disease virus in specific pathogen-free chickens. Veterinary World, 19 (2). pp. 591-603. ISSN 0972-8988; eISSN: 2231-0916 https://veterinaryworld.org/Vol.19/February-2026/10.php Veterinary (all) 10.14202/vetworld.2026.591-603
spellingShingle Veterinary (all)
Hair-Bejo, Mohd
Mazlan, Mazlina
Be, Tein Hock
Han, Chong Hao
Mohamed Sohaimi, Norfitriah
Ugwu, Chidozie Clifford
Pathogenicity, immunogenicity, and multi-organ tissue tropism of a novel variant infectious bursal disease virus in specific pathogen-free chickens
title Pathogenicity, immunogenicity, and multi-organ tissue tropism of a novel variant infectious bursal disease virus in specific pathogen-free chickens
title_full Pathogenicity, immunogenicity, and multi-organ tissue tropism of a novel variant infectious bursal disease virus in specific pathogen-free chickens
title_fullStr Pathogenicity, immunogenicity, and multi-organ tissue tropism of a novel variant infectious bursal disease virus in specific pathogen-free chickens
title_full_unstemmed Pathogenicity, immunogenicity, and multi-organ tissue tropism of a novel variant infectious bursal disease virus in specific pathogen-free chickens
title_short Pathogenicity, immunogenicity, and multi-organ tissue tropism of a novel variant infectious bursal disease virus in specific pathogen-free chickens
title_sort pathogenicity, immunogenicity, and multi-organ tissue tropism of a novel variant infectious bursal disease virus in specific pathogen-free chickens
topic Veterinary (all)
url http://psasir.upm.edu.my/id/eprint/123788/1/123788.pdf
http://psasir.upm.edu.my/id/eprint/123788/
https://veterinaryworld.org/Vol.19/February-2026/10.php
url_provider http://psasir.upm.edu.my/