Institute of Animal Husbandry and Veterinary Medicine, Fujian Academy of Agricultural Sciences /Fujian Animal Disease Control Technology Development Center, Fuzhou, Fujian 350013, China.
Institute of Animal Husbandry and Veterinary Medicine, Fujian Academy of Agricultural Sciences /Fujian Animal Disease Control Technology Development Center, Fuzhou, Fujian 350013, China.
Poult Sci. 2024 Apr;103(4):103552. doi: 10.1016/j.psj.2024.103552. Epub 2024 Feb 20.
The novel variant IBDV (nVarIBDV, genotype A2dB1), characterized by bursal atrophy of fabricius and decreased lymphocytes, has been emerging on a large scale in Asia (including China) since late 2018. nVarIBDV is a new threat to the poultry industry, yet the currently licensed commercial vaccines, including the live viral vector vaccine, IBDV immune complex vaccine or VP2 subunit vaccine, are ineffective against nVarIBDV infection. In this study, specific-pathogen-free (SPF) chickens and broilers divided into 3 groups were vaccinated with the live viral vector vaccine, the VP2 subunit vaccine or the IBDV immune complex vaccine at 1 day-old, respectively. The SPF chickens received a secondary vaccination with the live B87 strain vaccine at 11-day-old. The bursa/body weight ratio, histopathology lesion of the bursa, and the differentiation between infected and vaccinated animals (DIVA) by qRT-PCR confirmed that the live viral vector vaccine or immune complex vaccine plus live B87 strain booster could provide at least 80% protection against the FJ2019-01 strain of nVarIBDV in SPF chickens. The broilers also received a secondary vaccination using a live W2512 G-61 strain vaccine at 14-day-old, and analyses showed that the VP2 subunit vaccine or immune complex vaccine plus the live W2512 G-61 strain booster also provided more than 80% protection against the FJ2019-01 strain of nVarIBDV. Unfortunately, the live viral vector vaccine plus live W2512 G-61 strain booster provided poor to moderate protection against FJ2019-01 in broilers. These findings suggest that combining commercial vaccines with rational booster immunization can effectively protect chickens against an nVarIBDV challenge.
新型 IBDV（nVarIBDV，基因型 A2dB1），以法氏囊萎缩和淋巴细胞减少为特征，自 2018 年底以来在亚洲（包括中国）大规模出现。nVarIBDV 是家禽业的新威胁，但目前许可的商业疫苗，包括活病毒载体疫苗、IBDV 免疫复合物疫苗或 VP2 亚单位疫苗，对 nVarIBDV 感染无效。在这项研究中，将无特定病原体（SPF）鸡和肉鸡分为 3 组，分别在 1 日龄时接种活病毒载体疫苗、VP2 亚单位疫苗或 IBDV 免疫复合物疫苗。SPF 鸡在 11 日龄时接受活 B87 株疫苗的二次接种。通过 qRT-PCR 对法氏囊/体重比、法氏囊的组织病理学病变以及区分感染和免疫动物（DIVA）进行评估，证实活病毒载体疫苗或免疫复合物疫苗加活 B87 株加强免疫可对 SPF 鸡中的 FJ2019-01 株 nVarIBDV 提供至少 80%的保护。肉鸡还在 14 日龄时接受活 W2512 G-61 株疫苗的二次接种，分析表明 VP2 亚单位疫苗或免疫复合物疫苗加活 W2512 G-61 株加强免疫对 FJ2019-01 株 nVarIBDV 的保护率也超过 80%。不幸的是，活病毒载体疫苗加活 W2512 G-61 株加强免疫对 FJ2019-01 株在肉鸡中的保护效果不佳或中等。这些发现表明，将商业疫苗与合理的加强免疫相结合，可以有效地保护鸡免受 nVarIBDV 的挑战。
