Elvander M, Baule C, Persson M, Egyed L, Ballagi-Pordány A, Belák S, Alenius S
Department of Cattle and Sheep, National Veterinary Institute, Uppsala, Sweden.
Acta Vet Scand. 1998;39(2):251-64. doi: 10.1186/BF03547797.
Experimental infections with bovine respiratory syncytial virus (BRSV) and bovine viral diarrhoea virus (BVDV) were performed to study the effect of concurrent BRSV and BVDV infections. Twelve seronegative calves, in 3 groups, were inoculated on a single occasion with pure BRSV (group A), BRSV and noncytopathogenic BVDV (group B) or mock infected (group C). Mild respiratory symptoms were recorded 4 to 5 days post inoculation (dpi) in group A and group B calves. One calf in group A was severely affected and required medical treatment. In group B, fever (40.7-41.4 degrees C) was prominent 7 to 8 dpi. Only calves in group B were BVDV positive in purified lymphocytes at 2 to 14 dpi and showed increased serum interferon levels, with a peak at 4 dpi, indicating BVDV to be responsible for inducing the rise. BRSV was detected in lung lavage fluids up to 7 dpi for group A calves, compared to 11 dpi for group B and calves in this group also seroconverted later displaying lower BRSV titers. The time lag before an antibody response and the titers recorded in group B, indicated that the duration of BVDV infection in lymphocytes negatively influenced the capacity to mount a BRSV antibody response.
进行了牛呼吸道合胞病毒（BRSV）和牛病毒性腹泻病毒（BVDV）的实验性感染，以研究BRSV和BVDV并发感染的影响。将12头血清阴性的犊牛分为3组，一次性接种纯BRSV（A组）、BRSV和非致细胞病变的BVDV（B组）或进行 mock 感染（C组）。接种后4至5天（dpi），A组和B组犊牛出现轻度呼吸道症状。A组有一头犊牛受到严重影响，需要医疗救治。在B组中，接种后7至8天出现明显发热（40.7 - 41.4摄氏度）。仅B组犊牛在接种后2至14天，纯化淋巴细胞中的BVDV呈阳性，且血清干扰素水平升高，在4 dpi时达到峰值，表明BVDV是导致这种升高的原因。A组犊牛在肺灌洗液中检测到BRSV的时间长达7 dpi，而B组为11 dpi，且该组犊牛血清转化较晚，BRSV滴度较低。B组抗体反应出现的时间滞后以及记录的滴度表明，淋巴细胞中BVDV感染的持续时间对产生BRSV抗体反应的能力有负面影响。
