Calderón Bernal Johan Manuel, Fernández Ana, Arnal José Luis, Baselga Cristina, Benito Zuñiga Alfredo, Fernández-Garyzábal José Francisco, Vela Alonso Ana Isabel, Cid Dolores
Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.
Exopol. Veterinary Diagnostic and Autogenous Vaccine Laboratory, Polígono Río Gállego, D/8., 50840 San Mateo de Gállego, Zaragoza, Spain.
Vet Microbiol. 2023 May;280:109701. doi: 10.1016/j.vetmic.2023.109701. Epub 2023 Feb 17.
A hierarchical cluster analysis was used to classify outbreaks of bovine respiratory disease (BRD; n = 156) in natural groups according to the detection of nine pathogens (parainfluenza 3 virus (PI-3), bovine respiratory syncytial virus (BRSV), bovine coronavirus (BCV), bovine viral diarrhea virus (BVDV), and bovine herpesvirus 1 (BHV-1), Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis. Pathogens were detected by individual q-PCRs. Two clusters were identified. Cluster 1 was characterized by a relatively high frequency (40-72%) of four BRD-associated viruses, supporting their primary involvement in BRD. Cluster 2 was characterized by frequencies of PI-3, BRSV, or BVDV below 10% each. P. multocida and M. haemolytica were detected with high frequencies in both clusters (P > 0.05), while M. bovis and H. somni showed a significantly higher frequency in cluster 1and 2, respectively. Outbreaks in cluster 1 were associated with preweaning calves younger than 5 months (OR 2.2; 95% CI 1.1-4.5) and with cold months, whereas cluster 2 was associated with fattening calves older than 5 months after arrival to feedlots and without any seasonality. Thus, in addition to the classic epidemiological BRD pattern characterized by the primary involvement of viruses occurring preferably during winter and affecting young calves, there is a second pattern in which viruses would be less relevant, affecting mainly calves older than 5 months at any time of the year. This study allows a better understanding of the BRD epidemiology, which can be useful when implementing management and prophylaxis measures for a better control of this disease.
采用层次聚类分析方法，根据9种病原体（副流感3病毒（PI-3）、牛呼吸道合胞病毒（BRSV）、牛冠状病毒（BCV）、牛病毒性腹泻病毒（BVDV）、牛疱疹病毒1型（BHV-1）、溶血曼氏杆菌、多杀性巴氏杆菌、睡眠嗜组织菌和牛支原体）的检测结果，对自然群体中的牛呼吸道疾病（BRD；n = 156）暴发进行分类。病原体通过个体定量PCR检测。确定了两个聚类。聚类1的特征是四种与BRD相关病毒的频率相对较高（40-72%），支持它们在BRD中起主要作用。聚类2的特征是PI-3、BRSV或BVDV的频率均低于10%。多杀性巴氏杆菌和溶血曼氏杆菌在两个聚类中的检测频率均较高（P>0.05），而牛支原体和睡眠嗜组织菌分别在聚类1和聚类2中显示出显著更高的频率。聚类1中的暴发与5月龄以下的断奶前犊牛（OR 2.2；95%CI 1.1-4.5）以及寒冷月份有关，而聚类2与育肥场中5月龄以上到达育肥场的犊牛有关，且没有任何季节性。因此，除了以病毒主要参与、冬季多发且影响幼龄犊牛为特征的经典BRD流行病学模式外，还存在第二种模式，即病毒相关性较低，主要在一年中的任何时候影响5月龄以上的犊牛。这项研究有助于更好地理解BRD流行病学，这在实施管理和预防措施以更好地控制这种疾病时可能会有用。
