The introduction and spread of porcine epidemic diarrhoea virus (PEDV) in North America resulted in significant death loss in the swine industry. As the industry learned how to manage this disease, many new risks were identified, including the potential for feed and feed ingredients to become contaminated and spread PEDV. In addition, biosecurity practices were reevaluated and strengthened throughout the industry. At the time of the outbreak epidemiologists did not understand, as well as they are understood today, all the risk factors that contribute to the spread of PEDV. As a result, the epidemiological investigations into the 2014 PEDV outbreak in eastern Canada may not have investigated all risk factors as thoroughly as they would be investigated today. In retrospect, many of the Bradford Hill criteria used to determine causation were not fulfilled. This review identifies risk factors that were not included in the 2014 epidemiology. If these risk factors were included in the epidemiology, the conclusions and determination of causation may have been different.

中文翻译：

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加拿大2014年猪流行性腹泻病毒暴发：流行病学调查中未考虑的重要危险因素可能会改变结论。


猪流行性腹泻病毒（PEDV）在北美的传入和传播导致养猪业大量死亡。随着行业了解如何控制这种疾病，许多新的风险被识别出来，包括饲料和饲料原料被污染和传播 PEDV 的可能性。此外，整个行业的生物安全实践得到了重新评估和加强。在疫情爆发时，流行病学家并不了解导致 PEDV 传播的所有危险因素，正如他们今天所了解的那样。因此，对 2014 年加拿大东部 PEDV 疫情的流行病学调查可能没有像今天那样彻底调查所有风险因素。回想起来，许多用于确定因果关系的布拉德福德希尔标准都没有得到满足。本次审查确定了 2014 年流行病学中未包含的风险因素。如果将这些危险因素纳入流行病学研究中，得出的结论和因果关系的确定可能会有所不同。