Veterinary Epidemiology, Economics and Public Health Group, Department of Pathobiology and Population Science, Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire, AL9 7TA United Kingdom.
Veterinary Epidemiology, Economics and Public Health Group, Department of Pathobiology and Population Science, Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire, AL9 7TA United Kingdom.
J Dairy Sci. 2017 Nov;100(11):9215-9233. doi: 10.3168/jds.2016-11863. Epub 2017 Aug 23.
To implement appropriate and effective disease control programs at the national level, up-to-date and unbiased information on disease frequency is needed. The aim of this study was to estimate the prevalence of selected endemic infectious diseases in the population of dairy herds in Great Britain. Bulk milk tank (BMT) samples from 225 randomly selected dairy farms, stratified by region and herd size, were tested for antibodies against bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1, Mycobacterium avium ssp. paratuberculosis, Leptospira Hardjo, Salmonella spp., Coxiella burnetii, Fasciola hepatica, Neospora caninum, and Ostertagia ostertagi. Furthermore, the presence of BVDV, C. burnetii, and Chlamydia-like organisms was determined by PCR. The apparent herd prevalence was estimated as a weighted proportion of positive herds. The true prevalence was calculated when a test was used with known test characteristics for the cut-off value used. Among unvaccinated herds, the true prevalence of BMT antibodies against BVDV was estimated at 66% [95% confidence interval (CI): 56-77%], M. avium ssp. paratuberculosis 68% (95% CI: 59-77%), bovine herpesvirus type 1 62% (95% CI: 52-73%), Leptospira Hardjo 47% (95% CI: 34-60%), and Salmonella spp. 48% (95% CI: 39-56%). The apparent prevalence of BMT antibodies against C. burnetii was 80% (95% CI: 75-85%), F. hepatica 55% (95% CI: 48-62%), N. caninum 46% (95% CI: 38-54%), and O. ostertagi 95% (95% CI: 91-98%). The BVDV, C. burnetii, and Chlamydia-like antigens were detected in 5 (95% CI: 2-9%), 29 (95% CI: 21-36%), and 31% (95% CI: 24-38%) of herds, respectively. Our results show that dairy cows across GB are frequently exposed to the studied pathogens, which are endemic at high levels with some geographical variations. These prevalence estimates provide a much-needed basis to assess whether nationwide control programs for the studied pathogens are justified by their potential economic, environmental, and public health implications. Should surveillance and control programs be initiated, the estimates presented here are a baseline against which progress can be assessed.
为了在国家层面实施适当且有效的疾病控制计划，需要有关疾病频率的最新和无偏倚信息。本研究的目的是估计英国奶牛群中选定的地方性传染病的流行率。从 225 个随机选择的奶牛场的批量奶罐 (BMT) 样本中，根据地区和畜群规模进行分层，检测针对牛病毒性腹泻病毒 (BVDV)、牛疱疹病毒 1 型、禽分枝杆菌副结核亚种、钩端螺旋体 Hardjo、沙门氏菌、考克斯氏体、肝片吸虫、刚地弓形虫和奥斯特利希虫的抗体。此外，通过 PCR 确定 BVDV、C. burnetii 和类衣原体的存在。根据阳性畜群的加权比例估计明显的畜群流行率。当使用针对所用截止值具有已知测试特征的测试时，计算真实流行率。在未接种疫苗的畜群中，BVDV 的 BMT 抗体的真实流行率估计为 66%[95%置信区间 (CI)：56-77%]，禽分枝杆菌副结核亚种为 68% (95% CI：59-77%)，牛疱疹病毒 1 型为 62% (95% CI：52-73%)，钩端螺旋体 Hardjo 为 47% (95% CI：34-60%)，沙门氏菌为 48% (95% CI：39-56%)。BMT 针对 C. burnetii 的抗体的明显流行率为 80% (95% CI：75-85%)，肝片吸虫为 55% (95% CI：48-62%)，刚地弓形虫为 46% (95% CI：38-54%)，奥斯特利希虫为 95% (95% CI：91-98%)。BVDV、C. burnetii 和类衣原体抗原分别在 5 个 (95% CI：2-9%)、29 个 (95% CI：21-36%)和 31% (95% CI：24-38%)的畜群中检测到。我们的结果表明，英国各地的奶牛经常接触到这些研究中的病原体，这些病原体在高流行水平上流行，存在一些地理差异。这些流行率估计为评估研究病原体的全国性控制计划是否具有其潜在的经济、环境和公共卫生意义提供了急需的依据。如果启动监测和控制计划，这里提出的估计数将作为评估进展的基线。
