De Jong M C, van der Poel W H, Kramps J A, Brand A, van Oirschot J T
Department of Pathobiology and Epidemiology, Institute for Animal Science and Health, Lelystad, The Netherlands.
Am J Vet Res. 1996 May;57(5):628-33.
To determine if transmission of virus among seropositive cattle is a plausible mechanism for the permanent presence of bovine respiratory syncytial virus (BRSV) in dairy herds, and how likely, with the scenario for persistence, there will be only 1 clinical outbreak of BRSV per year.
Build a stochastic model, parameter estimation from serologic data on BRSV, and interpret the estimated parameter values from the model analysis.
Monthly data on the prevalence of antibodies directed against BRSV in sera from all cattle in 6 dairy herds.
Parameter estimation applying general linear models, model analysis using calculation of the reproduction ratio for simplified models, and Monte-Carlo simulation for the whole model.
Persistence of BRSV by transmission among seropositive cattle given estimated parameter values would be accompanied by frequent extinctions (once every 10 to 50 years) and long infectious periods in seropositive cattle (100 days). Moreover, in the model, a single clinical outbreak among seronegative cattle only occurred with external forcing.
From these data, transmission among seropositive cattle is not a plausible mechanism for persistence of BRSV in dairy herds.
确定血清反应阳性牛之间的病毒传播是否是奶牛群中牛呼吸道合胞病毒（BRSV）持续存在的一种合理机制，以及在这种持续存在的情况下，每年仅发生1次BRSV临床暴发的可能性有多大。
构建一个随机模型，根据BRSV的血清学数据进行参数估计，并从模型分析中解释估计的参数值。
6个奶牛群中所有牛血清中针对BRSV的抗体流行率的月度数据。
应用一般线性模型进行参数估计，使用简化模型的繁殖率计算进行模型分析，并对整个模型进行蒙特卡罗模拟。
根据估计的参数值，血清反应阳性牛之间的传播导致BRSV持续存在将伴随着频繁灭绝（每10至50年一次）以及血清反应阳性牛的长感染期（100天）。此外，在模型中，血清反应阴性牛中仅在有外部因素作用时才会发生单次临床暴发。
根据这些数据，血清反应阳性牛之间的传播不是BRSV在奶牛群中持续存在的合理机制。
