Makau Dennis N, Pamornchainavakul Nakarin, VanderWaal Kimberly, Kikuti Mariana, Picasso-Risso Catalina, Geary Emily, Corzo Cesar A
Department of Biomedical and Diagnostic Sciences College of Veterinary Medicine University of Tennessee, Knoxville, Tennessee, USA.
Department of Veterinary Population Medicine College of Veterinary Medicine University of Minnesota, Minneapolis, Minnesota, USA.
Transbound Emerg Dis. 2024 Oct 1;2024:5531899. doi: 10.1155/2024/5531899. eCollection 2024.
Porcine epidemic diarrhea virus (PEDV) emerged in the United States (U.S.) swine population in 2013, initiating an initial significant epidemic followed by a state of endemicity in the U.S. Despite continued monitoring, the epidemiology of PEDV during its endemic phase remains inadequately researched. Our study aimed to characterize the spatial-temporal distribution of postepidemic PEDV cases in the U.S. breeding herd and identify associated risk factors. Data from 1089 breeding farms in 27 states, reported to the Morrison Swine Health Monitoring Project from July 2014 to June 2021, were analyzed. We stratified the data into six U.S. regions and employed SaTScan for spatiotemporal permutation and cluster analysis. Survival analysis was used to assess risk factors. A notable seasonal clustering of PEDV cases was observed in winter (January-March; =0.001, relative risk = 2.2) with regional variation. Ten high-rate spatial-temporal clusters ( < 0.05) were identified ranging from 2.5 to 833.7 km and lasting 1-5 months, occurring in four regions between 2015 and 2021. For the study period, a total of 625 cases of PEDV were recorded on 372 farms. The total number of PEDV cases decreased from 95 breeding farms in 32 counties (2014-2015) to 53 farms in 28 counties (2020-2021), indicating an overall reduction in occurrence and spatial extent. Feed mitigants demonstrated a protective effect, significantly reducing the risk of PEDV occurrence (hazard ratio = 0.3, =0.003), while air filtration systems exhibited marginal benefits (hazard ratio = 0.3, =0.06). Other important risk factors included county farm density with farms in high-density regions (>31 farms/100 km) being 1.3 times more likely to experience outbreaks than in medium-density regions (13-31 farms/1000 km; < 0.001). Additionally, farms in region E had higher odds of outbreaks compared to region B. The overall decline in PEDV cases and reduced spatial extent reflect industry efforts in postepidemic control and elimination. The protective effects of feed mitigants warrant further investigation. Our findings underscore the opportunity for coordinated efforts to eliminate PEDV in the U.S. and emphasize the need for comprehensive risk profiling associated with industry practices.
猪流行性腹泻病毒（PEDV）于2013年在美国猪群中出现，引发了一场重大疫情，随后在美国进入地方流行状态。尽管持续进行监测，但PEDV在地方流行阶段的流行病学仍研究不足。我们的研究旨在描述美国种猪群中疫情后PEDV病例的时空分布，并确定相关风险因素。分析了2014年7月至2021年6月报告给莫里森猪健康监测项目的27个州1089个种猪场的数据。我们将数据分层为六个美国地区，并采用时空扫描法进行时空排列和聚类分析。生存分析用于评估风险因素。观察到PEDV病例在冬季（1月至3月；P = 0.001，相对风险 = 2.2）有明显的季节性聚集，且存在地区差异。确定了10个高发病率的时空聚类（P < 0.05），范围从2.5至833.7公里，持续1至5个月，于2015年至2021年期间在四个地区出现。在研究期间，372个农场共记录了625例PEDV病例。PEDV病例总数从2014 - 2015年32个县的95个种猪场减少到2020 - 2021年28个县的53个农场，表明发病率和空间范围总体上有所减少。饲料添加剂显示出保护作用，显著降低了PEDV发生的风险（风险比 = 0.3，P = 0.003），而空气过滤系统显示出边际效益（风险比 = 0.3，P = 0.06）。其他重要风险因素包括县农场密度，高密度地区（>31个农场/100平方公里）的农场爆发疫情的可能性是中密度地区（13 - 31个农场/1000平方公里）的1.3倍（P < 0.001）。此外，与B地区相比，E地区的农场爆发疫情的几率更高。PEDV病例的总体下降和空间范围的缩小反映了行业在疫情后控制和根除方面的努力。饲料添加剂的保护作用值得进一步研究。我们的研究结果强调了在美国协同努力消除PEDV的机会，并强调了与行业实践相关的全面风险评估的必要性。
