Zhou Yaping, Guo Ting, Zhao Hongmei, Hao Yongqing
Laboratory of Microbiology and Immunology, School of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China.
Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, Inner Mongolia, China.
Vet Med Sci. 2025 Sep;11(5):e70608. doi: 10.1002/vms3.70608.
Bovine respiratory disease complex (BRDC), a multifactorial syndrome driven by viral and bacterial co-infections, poses significant challenges to cattle health in northern China. We performed a large-scale epidemiological and phylogenetic investigation (2022-2024) to identify BRDC pathogens in the region. A total of 5052 samples from symptomatic Holstein calves (nasal swabs, sera, tissues) were analysed using virological, bacteriological and molecular methods. Viral pathogens-bovine viral diarrhoea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine parainfluenza virus-3 (BPIV-3) and bovine herpesvirus-1 (BHV-1)-dominated infections, with pronounced seasonal peaks in colder months. The prevalence of non-cytopathic BVDV highlighted clinical difficulties. Bacterial infections involved Mycoplasma bovis (M. bovis), Mannheimia haemolytica and Pasteurella multocida, with M. bovis prevalent in mixed infections. Phylogenetic analysis revealed biological connections between Chinese isolates and international strains (e.g., BVDV subgenotypes 1a/1d and BPIV-3c), showing global pathogen flow. Transmission electron microscopy revealed the presence of viral popular structure. Meanwhile, seasonality strongly influenced viral dynamics, while bacterial detection remained stable, involving environmental and management factors. Pathogen co-infections demonstrate the complexity of BRDC. This study provides the first comprehensive BRDC pathogen profile for northern China, emphasising the need for region-specific control strategies, including multipathogen vaccines and improved biosecurity.
牛呼吸道疾病综合征（BRDC）是一种由病毒和细菌共同感染引起的多因素综合征，给中国北方的牛健康带来了重大挑战。我们进行了一项大规模的流行病学和系统发育调查（2022 - 2024年），以确定该地区的BRDC病原体。使用病毒学、细菌学和分子方法对来自有症状的荷斯坦犊牛的5052份样本（鼻拭子、血清、组织）进行了分析。病毒病原体——牛病毒性腹泻病毒（BVDV）、牛呼吸道合胞病毒（BRSV）、牛副流感病毒3型（BPIV - 3）和牛疱疹病毒1型（BHV - 1）——主导感染，在较冷月份有明显的季节性高峰。非细胞病变性BVDV的流行突出了临床困难。细菌感染涉及牛支原体（M. bovis）、溶血曼氏杆菌和多杀性巴氏杆菌，M. bovis在混合感染中普遍存在。系统发育分析揭示了中国分离株与国际菌株（如BVDV亚型1a/1d和BPIV - 3c）之间的生物学联系，显示了全球病原体的传播。透射电子显微镜揭示了病毒颗粒结构的存在。同时，季节性强烈影响病毒动态，而细菌检测保持稳定，涉及环境和管理因素。病原体共同感染证明了BRDC的复杂性。本研究提供了中国北方首个全面的BRDC病原体概况，强调了制定针对该地区的控制策略的必要性，包括多病原体疫苗和改善生物安全措施。
