Dórea Fernanda C, Nöremark Maria, Widgren Stefan, Frössling Jenny, Boklund Anette, Halasa Tariq, Ståhl Karl
Department of Disease Control and Epidemiology, National Veterinary Institute (SVA), Uppsala, Sweden.
Department of Diagnostics and Scientific Advice, The National Veterinary Institute, Copenhagen, Denmark.
Front Vet Sci. 2017 Jul 24;4:118. doi: 10.3389/fvets.2017.00118. eCollection 2017.
To minimize the potential consequences of an introduction of foot-and-mouth disease (FMD) in Europe, European Union (EU) member states are required to present a contingency plan. This study used a simulation model to study potential outbreak scenarios in Sweden and evaluate the best control strategies. The model was informed by the Swedish livestock structure using herd information from cattle, pig, and small ruminant holdings in the country. The contact structure was based on animal movement data and studies investigating the movements between farms of veterinarians, service trucks, and other farm visitors. All scenarios of outbreak control included depopulation of detected herds, 3 km protection and 10 km surveillance zones, movement tracing, and 3 days national standstill. The effect of availability of surveillance resources, i.e., number of field veterinarians per day, and timeliness of enforcement of interventions, was assessed. With the estimated currently available resources, an FMD outbreak in Sweden is expected to be controlled (i.e., last infected herd detected) within 3 weeks of detection in any evaluated scenario. The density of farms in the area where the epidemic started would have little impact on the time to control the outbreak, but spread in high density areas would require more surveillance resources, compared to areas of lower farm density. The use of vaccination did not result in a reduction in the expected number of infected herds. Preemptive depopulation was able to reduce the number of infected herds in extreme scenarios designed to test a combination of worst-case conditions of virus introduction and spread, but at the cost of doubling the number of herds culled. This likely resulted from a combination of the small outbreaks predicted by the spread model, and the high efficacy of the basic control measures evaluated, under the conditions of the Swedish livestock industry, and considering the assumed control resources available. The results indicate that the duration and extent of FMD outbreaks could be kept limited in Sweden using the EU standard control strategy and a 3 days national standstill.
为将口蹄疫（FMD）传入欧洲可能造成的后果降至最低，欧盟（EU）成员国须提交一份应急计划。本研究使用模拟模型来研究瑞典可能出现的疫情情景，并评估最佳控制策略。该模型依据瑞典的牲畜结构构建，利用了该国牛、猪和小型反刍动物养殖场的畜群信息。接触结构基于动物移动数据以及对兽医、服务卡车和其他农场访客在农场间移动情况的调查研究。所有疫情控制情景均包括对检测到的畜群进行扑杀、设立3公里的保护区域和10公里的监测区域、追踪动物移动情况以及实施3天的全国性禁运。评估了监测资源的可用性（即每天的现场兽医数量）以及干预措施执行的及时性所产生的影响。根据目前估计可用的资源，在任何评估情景下，预计瑞典的口蹄疫疫情在检测到后的3周内能够得到控制（即检测到最后一个感染畜群）。疫情起始地区的农场密度对控制疫情所需时间影响不大，但与农场密度较低的地区相比，在高密度地区传播需要更多的监测资源。使用疫苗接种并未使预期的感染畜群数量减少。在旨在测试病毒引入和传播最坏情况组合的极端情景中，先发制人的扑杀能够减少感染畜群数量，但代价是扑杀畜群数量增加一倍。这可能是由于传播模型预测的小规模疫情爆发，以及在瑞典畜牧业条件下评估的基本控制措施的高效性，同时考虑到假定可用的控制资源。结果表明，采用欧盟标准控制策略并实施3天的全国性禁运，瑞典口蹄疫疫情的持续时间和范围可以得到限制。
