Laboratory of Animal Virology, Department of Veterinary Preventive Medicine, Universidade Estadual de Londrina, Brazil.
Section for Epidemiology, Norwegian Veterinary Institute, Norway.
Comp Immunol Microbiol Infect Dis. 2020 Aug;71:101494. doi: 10.1016/j.cimid.2020.101494. Epub 2020 May 11.
The etiological agents involved in a bovine respiratory disease (BRD) outbreak were investigated in a dairy heifer calf rearing unit from southern Brazil. A battery of PCR assays was performed to detect the most common viruses and bacteria associated with BRD, such as bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine alphaherpesvirus 1 (BoHV-1), bovine coronavirus (BCoV), bovine parainfluenza virus 3 (BPIV-3), , , , and . Bronchoalveolar lavage fluid (BALF) samples were taken from 21 heifer calves (symptomatic = 15; asymptomatic = 6) that, during the occurrence of the BDR outbreak, were aged between 6 and 90 days. At least one microorganism was detected in 85.7 % (18/21) of the BALF samples. Mixed infections were more frequent (72.2 %) than single infections (27.7 %). The interactions between viruses and bacteria were the most common in coinfections (55.5 %). The frequencies of BRD agents were 38.1 % for BRSV, 28.6 % for BVDV, 33.3 % for BCoV, 42.85 % for 33.3 % for , and 19 % for . BoHV-1, BPIV-3, and were not identified in any of the 21 BALF samples. Considering that BALF and not nasal swabs were analyzed, these results demonstrate the etiological multiplicity that may be involved in BRD outbreaks in dairy calves.
巴西南部一个奶牛小母牛饲养单位发生了牛呼吸道疾病（BRD）暴发，对涉及的病原体进行了调查。该研究采用了一系列 PCR 检测方法，以检测与 BRD 相关的最常见病毒和细菌，如牛病毒性腹泻病毒（BVDV）、牛呼吸道合胞体病毒（BRSV）、牛α疱疹病毒 1 型（BoHV-1）、牛冠状病毒（BCoV）、牛副流感病毒 3 型（BPIV-3）、、、和。从 21 头小母牛（有症状的 = 15 头；无症状的 = 6 头）的支气管肺泡灌洗液（BALF）样本中检测到至少一种微生物，这些小母牛在发生 BDR 暴发时的年龄在 6 至 90 天之间。在 85.7%（18/21）的 BALF 样本中检测到至少一种微生物。混合感染比单一感染更为常见（72.2%比 27.7%）。在共感染中，病毒和细菌之间的相互作用最为常见（55.5%）。BRD 病原体的检出率分别为 BRSV 38.1%、BVDV 28.6%、BCoV 33.3%、 33.3%、和 19%。BoHV-1、BPIV-3 和 未在 21 个 BALF 样本中的任何一个中被鉴定出来。由于分析的是 BALF 而不是鼻拭子，这些结果表明，在奶牛犊牛的 BRD 暴发中可能涉及多种病因。
