Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, UPM Serdang, Selangor Darul Ehsan 43400, Malaysia.
Avian Unit, Veterinary Teaching Hospital, Ahmadu Bello University, Zaria, P.M.B. 1045, Nigeria.
J Vet Sci. 2024 Sep;25(5):e70. doi: 10.4142/jvs.23297.
Infectious bursal disease (IBD) is an important viral poultry disease that vaccination can control.
This study examined the immune protection of immune-complex (Vaccine A) and attenuated live (Vaccine B) IBD vaccines in specific-pathogen-free (SPF) chickens against a novel Malaysian variant IBD virus (vaIBDV) challenge.
One-day-old (n =75) SPF chickens were divided randomly into the following three groups of 25 chicks each: Control, Vaccine A, and Vaccine B groups. The vaIBDV strain, UPM1432/2019, was used for the challenge at 21 and 28days post-vaccination (dpv). Five birds from unchallenged and challenged groups were sacrificed seven days post-challenge, and blood, bursa, spleen, and cloacal swabs were collected. The IBD antibodies (Abs), lymphoid lesions, and viral load were determined.
The UPM1432/2019 virus induced bursal damage in vaccinated SPF chickens despite Ab titers. The mean Ab titers of the Vaccine A challenged group were significantly lower ( < 0.002) than in the unchallenged group at 28 dpv. The bursal indices of the vaccinated unchallenged groups did not differ significantly from those of the vaccinated challenged groups ( = 0.94). Microscopically, the bursae of the challenged groups showed significant atrophy. The bursal lesion score was higher ( < 0.05) in the control and Vaccine B challenged groups than the Vaccine A challenged group. The challenged group had a higher viral load than the vaccinated groups ( < 0.001).
Neither vaccine fully protected against a vaIBDV challenge, highlighting the limitations of current vaccines and the need for further research.
传染性法氏囊病（IBD）是一种重要的病毒性禽类疾病，可以通过疫苗接种来控制。
本研究检测了免疫复合物（疫苗 A）和减毒活疫苗（疫苗 B）对无特定病原体（SPF）鸡在新型马来西亚变异传染性法氏囊病病毒（vaIBDV）攻毒时的免疫保护作用。
将 1 日龄（n =75）SPF 鸡随机分为以下三组，每组 25 只鸡：对照组、疫苗 A 组和疫苗 B 组。在接种后 21 天和 28 天（dpv），使用 UPM1432/2019 株作为攻毒毒株。在攻毒后第 7 天，从未攻毒和攻毒组中各随机选择 5 只鸡进行安乐死，采集血液、法氏囊、脾脏和泄殖腔拭子。检测 IBD 抗体（Abs）、淋巴病变和病毒载量。
尽管有 Ab 滴度，但 UPM1432/2019 病毒还是会引起接种 SPF 鸡的法氏囊损伤。疫苗 A 攻毒组的平均 Ab 滴度在 28 dpv 时明显低于未攻毒组（<0.002）。接种疫苗的未攻毒组和攻毒组的法氏囊指数没有显著差异（=0.94）。显微镜下，攻毒组的法氏囊明显萎缩。与疫苗 A 攻毒组相比，对照组和疫苗 B 攻毒组的法氏囊病变评分更高（<0.05）。攻毒组的病毒载量高于接种组（<0.001）。
两种疫苗都不能完全预防 vaIBDV 攻毒，这突显了当前疫苗的局限性，需要进一步研究。
