Hagenaars T J, Donnelly C A, Ferguson N M
Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, St Mary's Campus, Norfolk Place, London, UK.
Epidemiol Infect. 2006 Apr;134(2):359-67. doi: 10.1017/S0950268805004966.
In recent years, the control or eradication of scrapie and any other transmissible spongiform encephalopathies (TSEs) possibly circulating in the sheep population has become a priority in Britain and elsewhere in Europe. A better understanding of the epidemiology of scrapie would greatly aid the development and evaluation of control and eradication strategies. Here we bound the range of key epidemiological parameters using a combination of relatively detailed pathogenesis and demography data, more limited data on susceptibility and incubation times, and recent survey data on scrapie incidence in Great Britain. These data are simultaneously analysed using mathematical models describing scrapie transmission between sheep and between flocks. Our analysis suggests that occurrence of scrapie in a flock typically provokes changes in flock management that promote termination of the outbreak, such as the adoption of selective breeding, and that a large fraction of cases (possibly over 80%) goes undetected. We show that the data analysed are consistent with the within-flock reproduction number of scrapie lying in the range 1.5-6, consistent with previous epidemiological studies.
近年来，在英国和欧洲其他地区，控制或根除羊瘙痒病以及可能在绵羊群体中传播的任何其他传染性海绵状脑病（TSEs）已成为首要任务。更好地了解羊瘙痒病的流行病学将极大地有助于控制和根除策略的制定与评估。在此，我们结合相对详细的发病机制和人口统计学数据、关于易感性和潜伏期的更有限数据以及英国近期羊瘙痒病发病率的调查数据，确定了关键流行病学参数的范围。使用描述绵羊之间和羊群之间羊瘙痒病传播的数学模型对这些数据进行了同时分析。我们的分析表明，羊群中羊瘙痒病的出现通常会引发羊群管理的变化，从而促进疫情的终止，例如采用选择性育种，而且很大一部分病例（可能超过80%）未被发现。我们表明，所分析的数据与羊瘙痒病在羊群内的繁殖数在1.5至6的范围内一致，这与先前的流行病学研究一致。
