Industry-Wide Surveillance of Marek's Disease Virus on Commercial Poultry Farms.
Industry-Wide Surveillance of Marek's Disease Virus on Commercial Poultry Farms.
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DOI：
10.1637/11525-110216-reg.1
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发表时间：
2017-06
期刊：
影响因子：
1.4
通讯作者：
Read AF
中科院分区：
文献类型：
--
作者：
Kennedy DA;Cairns C;Jones MJ;Bell AS;Salathé RM;Baigent SJ;Nair VK;Dunn PA;Read AF
马立克氏病病毒是一种鸡疱疹病毒，每年给全球家禽业造成超过10亿美元的损失。在过去的半个世纪，由于病毒的进化，两代马立克氏病疫苗显示出降低的效力。了解病毒存在的位置可能有助于了解疗效是否可能继续降低。我们进行了一项为期三年的监测研究，以评估马立克氏病病毒在商业家禽养殖场的流行情况，确定各种因素对病毒流行的影响，并记录肉鸡鸡舍在短（数周）和长（数年）时间尺度上的病毒动态。我们从美国宾夕法尼亚州的商业鸡肉和鸡蛋生产设施收集的灰尘样本中提取了DNA。使用定量聚合酶链反应（qPCR）评估野生型病毒的可检测性和浓度。使用贝叶斯广义线性混合效应模型从1018个灰尘样本的数据，我们确定了与病毒在农场的流行相关的因素。最大似然和自相关函数估计3727额外的灰尘样本被用来记录和表征随着时间的推移，在房屋内的病毒浓度。总体而言，野生型病毒在104个农场中的36个农场中至少检测到一次，农场之间的比率差异很大。在1/3家肉鸡养殖企业（公司）、4/5家肉鸡养殖企业和3/5家蛋鸡养殖企业中检测到病毒。马立克氏病病毒的可检测性因生产类型、禽龄、一年中的日期、操作（公司）、农场、房屋、鸡群和样品而异。操作（公司）是最重要的因素，占病毒可检测性变化的12%至63.4%。在个别房屋内，病毒浓度往往下降到可检测的水平以下，随后又重新出现。这些数据描述了马立克氏病病毒动态，这对病毒的进化可能很重要。
Marek’s disease virus is a herpesvirus of chickens that costs the worldwide poultry industry over 1 billion USD annually. Two generations of Marek’s disease vaccines have shown reduced efficacy over the last half century due to evolution of the virus. Understanding where the virus is present may give insight into whether continued reductions in efficacy are likely. We conducted a three-year surveillance study to assess the prevalence of Marek’s disease virus on commercial poultry farms, determine the effect of various factors on virus prevalence, and document virus dynamics in broiler chicken houses over short (weeks) and long (years) timescales. We extracted DNA from dust samples collected from commercial chicken and egg production facilities in Pennsylvania, USA. Quantitative polymerase chain reaction (qPCR) was used to assess wild-type virus detectability and concentration. Using data from 1018 dust samples with Bayesian generalized linear mixed effects models, we determined the factors that correlated with virus prevalence across farms. Maximum likelihood and autocorrelation function estimation on 3727 additional dust samples were used to document and characterize virus concentrations within houses over time. Overall, wild-type virus was detectable at least once on 36 of 104 farms at rates that varied substantially between farms. Virus was detected in 1 of 3 broiler-breeder operations (companies), 4 of 5 broiler operations, and 3 of 5 egg layer operations. Marek’s disease virus detectability differed by production type, bird age, day of the year, operation (company), farm, house, flock, and sample. Operation (company) was the most important factor, accounting for between 12% and 63.4% of the variation in virus detectability. Within individual houses, virus concentration often dropped below detectable levels and reemerged later. These data characterize Marek’s disease virus dynamics, which are potentially important to the evolution of the virus.