Halasa Tariq, Boklund Anette
Section of Epidemiology, the National Veterinary Institutes, Technical University of Denmark, Copenhagen, Denmark.
PLoS One. 2014 Jul 11;9(7):e102480. doi: 10.1371/journal.pone.0102480. eCollection 2014.
The objectives of this study were to assess whether current surveillance capacity is sufficient to fulfill EU and Danish regulations to control a hypothetical foot-and-mouth disease (FMD) epidemic in Denmark, and whether enlarging the protection and/or surveillance zones could minimize economic losses. The stochastic spatial simulation model DTU-DADS was further developed to simulate clinical surveillance of herds within the protection and surveillance zones and used to model spread of FMD between herds. A queuing system was included in the model, and based on daily surveillance capacity, which was 450 herds per day, it was decided whether herds appointed for surveillance would be surveyed on the current day or added to the queue. The model was run with a basic scenario representing the EU and Danish regulations, which includes a 3 km protection and 10 km surveillance zone around detected herds. In alternative scenarios, the protection zone was enlarged to 5 km, the surveillance zone was enlarged to 15 or 20 km, or a combined enlargement of the protection and surveillance zones was modelled. Sensitivity analysis included changing surveillance capacity to 200, 350 or 600 herds per day, frequency of repeated visits for herds in overlapping surveillance zones from every 14 days to every 7, 21 and 30 days, and the size of the zones combined with a surveillance capacity increased to 600 herds per day. The results showed that the default surveillance capacity is sufficient to survey herds on time. Extra resources for surveillance did not improve the situation, but fewer resources could result in larger epidemics and costs. Enlarging the protection zone was a better strategy than the basic scenario. Despite that enlarging the surveillance zone might result in shorter epidemic duration, and lower number of affected herds, it resulted frequently in larger economic losses.
本研究的目的是评估当前的监测能力是否足以满足欧盟和丹麦的法规要求，以控制丹麦假设的口蹄疫（FMD）疫情，以及扩大保护区和/或监测区是否可以将经济损失降至最低。进一步开发了随机空间模拟模型DTU-DADS，以模拟保护区和监测区内畜群的临床监测，并用于模拟口蹄疫在畜群之间的传播。模型中纳入了一个排队系统，并根据每天450个畜群的日常监测能力，决定指定监测的畜群是在当天进行调查还是加入队列。该模型在代表欧盟和丹麦法规的基本情景下运行，其中包括在检测到的畜群周围设置3公里的保护区和10公里的监测区。在替代情景中，将保护区扩大到5公里，将监测区扩大到15或20公里，或者对保护区和监测区进行联合扩大建模。敏感性分析包括将监测能力改为每天200、350或600个畜群，将重叠监测区内畜群的重复访问频率从每14天改为每7、21和30天，以及将区域大小与监测能力提高到每天600个畜群相结合。结果表明，默认的监测能力足以按时对畜群进行调查。额外的监测资源并没有改善情况，但资源减少可能导致更大规模疫情和成本增加。扩大保护区是比基本情景更好的策略。尽管扩大监测区可能会缩短疫情持续时间，减少受影响畜群数量，但它经常会导致更大的经济损失。
