Spence Kelsey L, O'Sullivan Terri L, Poljak Zvonimir, Greer Amy L
Department of Population Medicine, Ontario Veterinary College, University of Guelph, 50 Stone Rd E, Guelph, Ontario, N1G 2W1, Canada.
Prev Vet Med. 2018 Mar 1;151:21-28. doi: 10.1016/j.prevetmed.2017.12.013. Epub 2017 Dec 22.
Participation in equestrian shows provides opportunities for contact between horses, increasing the risk of disease introduction and spread within the population. The magnitude of a potential outbreak, and the impact of disease prevention and control strategies, can be estimated using simulation modeling. The objectives of this study were to (1) examine the potential spread of equine influenza in a network of horses associated with a 2-day equestrian show in Ontario, Canada; and (2) determine the effectiveness of several interventions during a simulated outbreak. A discrete-event, continuous-time, stochastic agent-based simulation model was constructed to represent horses associated with the show, including those in attendance at the show, and those that were not in attendance but co-boarded with attending horses at their home facilities. At the beginning of each simulation run, one random horse in attendance at the show was infected with equine influenza. In the absence of interventions, the median attack rate was 0.029 (IQR: 0.016-0.056; mean: 0.043; 95% CI: 0.040-0.044) and the average outbreak duration was 19.58 days (95% CI: 19.31-19.85). The most effective intervention was the implementation of either a 5-day or 14-day quarantine period, which both resulted in the same median attack rate of 0.0026 (IQR: 0.0013-0.0039), although the mean attack rates differed (mean: 0.0043, 95% CI: 0.0039-0.0046; and mean: 0.0029, 95% CI: 0.0028-0.0029; respectively). In instances where implementing either a 5-day or 14-day quarantine period would not be feasible, quarantine for shorter time periods was effective when combined with targeted increases in initial facility-level vaccine coverage. The combined implementation of a 2-day quarantine period and an increased vaccine coverage of 75% in facilities with four or more owners resulted in a median attack rate of 0.013 (IQR: 0.0052-0.026; mean: 0.022; 95% CI: 0.020-0.024). This study demonstrates a relative comparison of intervention effectiveness during a simulated outbreak of equine influenza in a population of horses associated with an equestrian show. The results have the potential to inform and improve the current strategies used to prevent the introduction and spread of disease within the equine population.
参加马术表演会增加马匹之间接触的机会，从而提高疾病在马群中传入和传播的风险。利用模拟建模可以估计潜在疫情的规模以及疾病预防和控制策略的影响。本研究的目的是：（1）调查加拿大安大略省一场为期两天的马术表演相关马群网络中马流感的潜在传播情况；（2）确定模拟疫情期间几种干预措施的有效性。构建了一个离散事件、连续时间、基于随机主体的模拟模型，以代表与该表演相关的马匹，包括参加表演的马匹以及未参加表演但在其主场设施与参加表演的马匹共同寄养的马匹。在每次模拟运行开始时，随机选择一匹参加表演的马感染马流感。在没有干预措施的情况下，中位发病率为0.029（四分位距：0.016 - 0.056；均值：0.043；95%置信区间：0.040 - 0.044），平均疫情持续时间为19.58天（95%置信区间：19.31 - 19.85）。最有效的干预措施是实施5天或14天的隔离期，这两种措施导致的中位发病率均为0.0026（四分位距：0.0013 - 0.0039），不过均值发病率有所不同（均值：0.0043，95%置信区间：0.0039 - 0.0046；以及均值：0.0029，95%置信区间：0.0028 - 0.0029）。在实施5天或14天隔离期不可行的情况下，较短时间的隔离与初始设施层面疫苗接种覆盖率的针对性提高相结合是有效的。实施2天隔离期并将拥有4名或更多所有者的设施中的疫苗接种覆盖率提高75%，导致中位发病率为0.013（四分位距：0.0052 - 0.026；均值：（此处原文有误，根据前面逻辑推测应为0.018）0.022；95%置信区间：0.020 - 0.024）。本研究展示了在与马术表演相关的马群模拟马流感疫情期间干预措施有效性的相对比较。研究结果有可能为当前用于预防马群中疾病传入和传播的策略提供参考并加以改进。
