译者的话：
人员入场隔离期多长时间合适？4晚、7天、14天？在即将来临的低价低利润养殖时期，任何成本的浪费或者冗余都会降低企业的竞争力，隔离期的长短不仅仅是劳务成本的增加，相应隔离设施、检测、物流成本也会增加。本实验在长达近四年观察监测期中，多角度的对比不同生物安全措施/等级和隔离期对蓝耳病（美国高致病性毒株）和气喘病传播的影响：14-16个小时的淋浴更衣换鞋+隔离是可以阻断蓝耳病毒和气喘病的传播的，累计45分钟的淋浴更衣换鞋隔离期在短期对比实验中也显示了有效性。此实验结果是对既往较长的隔离期的一种挑战，也是对包括非瘟在内其他疫病的隔离期的设定的一种思考，抛玉引玉，期待着国内有类似的研究信息共享。
同行评审
一晚的隔离时间可以防止猪繁殖和呼吸综合症病毒和猪肺炎支原体通过人员和污染物(靴子和工作服)传播（下）
A one-night downtime period prevents the spread of porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae by personnel and fomites (boots and coveralls) - Part 2
作者 Authors
Andrea Pitkin, MS
Satoshi Otake, DVM, PhD
Scott Dee, DVM, MS, PhD, Diplomate ACVM
概要 Summary
本文总结了4年(1438天)的观察记录，关于一晚的隔离时间对防止猪繁殖和呼吸综合征病毒和猪肺炎支原体通过人员和污染物在猪群间机械传播的能力。
This paper summarizes observations recorded over a 4-year (1438-day) period regarding the ability of a 1-night period of downtime to prevent mechanical spread of porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae between pig populations by personnel and fomites.
关键词：猪，猪繁殖和呼吸综合症，隔离，人员，污染物
Keywords: swine, porcine reproductive and respiratory syndrome, downtime, personnel, fomites
控制组 Controls
除了每天对动物、人和无生命物体采样，还进行了两套控制实验，即PRRSV扩散控制和PRRSV隔离期控制。这些控制不包括Mhyo，因为它们是在研究的第一年执行的，那时PRRSV是之前在猪群中接种的唯一病原体。传播控制的目的是记录PRRSV是否通过人员和污染物接触感染动物后传染给哨兵猪(图2)。在连续5天内，1人接触了猪群内的感染动物，然后在不经过任何基本清洁措施(淋浴、洗手、换工作服和靴子)的情况下到高级别生物安全设施中立即接触了阴性哨兵猪(10头6至8周大的猪)。隔离期的控制的目的是记录人员和污染物所造成的PRRSV传播是否可以通过基本的清洁措施来防止(图3)。连续5天，有1名人员在猪群中接触了感染的猪，然后立即去往高级别生物安全设施接触哨兵猪，那里有10头6至8周龄的阴性哨兵猪。在进入高级别设施之前，这名人员在接触不同组的猪之间都会洗澡，更换工作服和靴子，但没有遵守指定的隔离时间。对照组被分开圈养，以防止直接和间接接触。按照上述情况进行日常动物护理，使每组动物和工作人员之间有广泛的身体接触。此外，如前所述，在指定地点采集日常工作人员拭子和污染物拭子(图2和图3)。另外，两个对照组的哨兵猪在第0天(抵达哨点设施时)、第5天(5天接触期结束时)和第20天(接触期结束后15天)进行了血液检测。在MN VDL通过PCR检测血液样本是否存在PRRSV RNA。
In addition to the daily sampling of animals, people, and inanimate objects, two sets of control protocols, the PRRSV Spread Control and the PRRSV Downtime Control, were conducted. These controls did not involve Mhyo because they were conducted during year 1 of the study, when PRRSV was the only pathogen previously inoculated in the source population. The objective of the Spread Control was to document whether PRRSV spread to naive sentinels had occurred by personnel and fomites following contact with infected animals (Figure 2). For 5 consecutive days, one person contacted infected animals in the source population and then immediately contacted naive sentinels (n = 10 pigs 6 to 8 weeks of age) in the high-level biosecurity building in the absence of basic sanitary measures (showering, washing hands, changing coveralls and boots). The objective of the Downtime Control was to document whether PRRSV transmission by personnel and fomites could be prevented by basic sanitary measures (Figure 3). For 5 consecutive days, one person moved from the source population to the high-level biosecurity building, which contained 10 naive sentinel pigs 6 to 8 weeks of age. Before entering the high-level building, this person took a shower and changed coveralls and boots between groups, but did not observe a designated period of downtime. The control groups were housed separately to prevent direct and indirect contact. Daily animal care was practiced as described, which allowed for extensive physical contact between animals and personnel in each group. In addition, daily personnel swabs and fomite swabs were collected at designated points (Figures 2 and 3) as previously described. Furthermore, sentinel animals in both control groups were blood tested on Day 0 (on arrival at the sentinel facility), on Day 5 (at the end of the 5-day contact period) and on Day 20 (15 days after completion of the contact period). Blood samples were tested for the presence of PRRSV RNA by PCR at the MN VDL.
图1：各设施及人员日常流动示意图。研究人员每天在现场住所淋浴并穿上干净的衣服和鞋子，之后进入高级生物安全设施(空气过滤的)，穿上干净的衣服和靴子并洗手，然后进入有猪的区域，这些猪是猪繁殖和呼吸综合征病毒(PRRSV)和肺炎支原体(Mhyo)的双阴性猪。在与动物接触之前，采集手上、工作服和靴子上的拭子，用聚合酶链反应检测PRRSV RNA和Mhyo DNA。在完成动物护理任务后，工作人员进入猪场，那里有300头感染了PRRSV和Mhyo的猪只。完成动物护理工作后，工作人员重新进入住所，他们在那里洗澡，穿上干净的衣服，并保持1晚不接触动物。第二天早上，重复此过程。这种人员流动模式重复了1438天。
图2：猪繁殖与呼吸综合征病毒(PRRSV)传播控制实验中的人员流动总结图。该实验的目的是证明在没有特定生物安全控制的情况下，PRRSV可以通过人员和污染物从受感染的猪群传播到阴性猪群。对照实验连续进行5天，每天在进入高级别生物安全设施时从手、工作服和靴子上采集棉拭子，并用聚合酶链反应检测PRRSV RNA。
图3：猪繁殖和呼吸综合征病毒(PRRSV)隔离期控制实验中的人员流动总结图。该实验的目的是记录是否可以采取基本的卫生措施来防止通过人员和污染物造成的PRRSV传播。控制方案连续进行了5天，包括人员在淋浴和更换衣服和鞋类后从PRRS阳性猪群直接前往高级生物安全设施。在进入后一个设施时，采集手、工作服和靴子上的拭子，并通过聚合酶链反应检测PRRSV RNA。
结果 Results
在为期1438天的研究期间，共有25名人员参与了上述设施之间的活动。分别采集和检测了7174个人员样本和4833个污染物样本（PRRSV RNA和Mhyo DNA检测）。在4年的研究期间，所有拭子均为PCR阴性，且高水平生物安全设施中饲养的所有动物( 480只)均为PRRSV阴性和Mhyo阴性。清洁和隔离时间每天大约持续14至16小时。在扩散控制实验中，观察到PRRSV的二次机械传播是由接触受污染的人员和污染物引起的。暴露第5天，10个哨兵猪中有5个PRRSv阳性，而暴露第20天，10个哨兵猪中有10个PRRSv阳性。此外，在与猪群中的受感染动物接触后进入高生物安全设施时采集的人员和污染物标本，其中45个棉签中有40个检测到PRRSV RNA。相反，PRRSV在隔离控制期内到哨兵猪的传播被阻止，因为所有哨兵猪在测试期间保持PRRSV阴性。在所有5天暴露时间中，直到离开猪群，在人员和污染物的45个棉拭子中有42个检测到PRRSV RNA。在淋浴和更换靴后进入哨兵猪设施时采集的所有拭子(45 / 45)均为PCR阴性。不同组的猪只间，人员洗澡、换工作服和靴子的时间大约是45分钟。
Over the course of the 1438-day study period, a total of 25 people were involved in movements and activities between the aforementioned facilities. A total of 7174 and 4833 personnel and fomite samples, respectively, were tested for PRRSV RNA and Mhyo DNA. All swabs were PCR-negative and all animals (n = 480) housed in the high-level biosecurity facility remained PRRSV-naive and Mhyo-naive throughout the entire 4-year study period. The approximate duration of the sanitation and downtime period was 14 to 16 hours each day. Mechanical spread of PRRSV secondary to contact with contaminated personnel and fomites was observed during the Spread Control protocol. Five of 10 sentinels were PRRSV-positive on Day 5 post exposure, while 10 of 10 sentinels were PRRSV-positive on Day 20 post exposure. In addition, PRRSV RNA was detected on 40 of 45 swabs collected from personnel and fomites upon entry into the high-biosecurity facility following contact with the infected animals in the source population. In contrast, PRRSV transmission to sentinels was prevented during the Downtime Control protocol, as all sentinels remained PRRSV-negative over the testing period. While PRRSV RNA was detected on 42 of 45 swabs from personnel and fomites collected upon exiting the source population across all 5 exposure days, all swabs (45 of 45) collected upon entry into the sentinel facility following a shower and coverall-boot change were PCR-negative. The time required to shower and change coveralls and boots between groups was approximately 45 minutes.
讨论 Discussion
在撰写本报告所用的条件下，隔离时间为1晚(持续14至16小时)防止了PRRSV和Mhyo在感染猪群和易感猪群之间通过人员和污染物传播。虽然这些信息本质上是观察得出的，并且是在模型条件下收集的，但它对延长隔离时间的有效性提出了挑战。另外，虽然以前报道过关于数据描述污染物和人员机械传播PRRSV的能力[4,5]，以及降低这些风险的干预策略的研究，但这项新研究是新颖的和严谨的、因为这些观察是经过一段长时间收集的，涉及众多人员，采用广泛的基于抗原的取样程序，包括一组基于PRRSV的控制实验。遗憾的是，由于研究设计的限制，大量的对照，以及一组Mhyo对照，不能包括在内。此外，本研究不需要采集人员的鼻拭子。这一决定是基于之前的一项研究中[3]，从人类鼻腔样本中重获的PRRSV RNA仅限于暴露48小时后收集的单个样本。这是作者的观点，如果这的确是一个真实的结果，那么我们预期检测到的频率将更大，最初检测到的时间应该发生在暴露后的早期，而病毒也会在更多的研究人员身上被检测到。最后，由于我们的研究周期很长，而且过程的侵入性，因此不可能在如此多的参与者中强制执行。
Under the conditions utilized to compile this report, a downtime period of 1 night (14 to 16 hours in duration) prevented the spread of PRRSV and Mhyo by personnel and fomites between infected and susceptible populations. While the information is strictly observational in nature and was collected under model conditions, it challenges the validity of extended downtime periods. Furthermore, while data describing the ability of fomites and personnel to mechanically transmit PRRSV, along with intervention strategies to reduce these risks, have been previously published,4,5 this new study is novel and rigorous, as the observations were collected over an extended period of time, involved numerous people, employed an extensive antigen-based sampling procedure, and included a set of control protocols based on PRRSV. Unfortunately, due to study-design limitations, a larger number of controls, as well as a set of Mhyo controls, could not be included. In addition, this study did not require the collection of nasal swabs from personnel. This decision was based on the fact that in a previous study,3 recovery of PRRSV RNA from human nasal samples was limited to a single sample collected 48 hours post exposure. It was the authors’ opinion that if this was indeed a true result, we would have expected that the frequency of detection would have been greater, that the initial detection would have occurred at an early period(s) post exposure, and that virus would have been detected in a larger number of study personnel. Finally, due to the length of our study period and the invasiveness of the procedure, it would have been impossible to enforce compliance over such a large number of participants.
总之，尽管这些观察结果很有趣，并且有潜力提高养猪业人员隔离政策的有效性，但显然还需要更多的研究来调查和澄清这个问题。例如，由于这些观察结果仅适用于PRRSV和Mhyo，我们不知道它们是否可在其他病原体中使用，如猪圆环病毒2型或猪流感病毒。最终，我们也没有确定防止病原体传播所需的最短隔离时间。基于这些关于PRRSV和Mhyo的观察，任何时长的隔离都可以被认为是“浪费的时间”。但是，由于我们的对照使用不包括Mhyo，所以在没有更多数据的情况下，我们无法得出任何肯定的结论。理想情况下，如果未来的研究可以回答这些问题，并且可以在整个行业的决策者之间进行有组织的讨论，也许可以在行业领导者之间达成一致，从而形成一个国际性的隔离计划。在此之前，我们希望从该报告中得到的观察将会在早期的适应者之间发起讨论，指导决策制定，并促进那些已经被这些数据说服的人所拥有和操作的体系之间的变化。
In conclusion, while these observations are intriguing and have the potential to improve the efficacy of the personnel downtime policies within the industry, more research is clearly needed to investigate and clarify questions which still exist surrounding this issue. For example, since these observations are applicable only to PRRSV and Mhyo, we do not know whether they would be repeatable across other pathogens such as porcine circovirus type 2 or swine influenza virus. Nor have we conclusively determined the minimum amount of downtime required to prevent pathogen spread. On the basis of these observations regarding PRRSV and Mhyo, any amount of downtime could be considered “wasted time.” However, since our controls did not include Mhyo, we cannot draw any affirmative conclusions without more data. Ideally, if future studies could answer these questions, and an organized discussion could take place across decision makers throughout the industry, perhaps agreement across industry leaders could be reached, resulting in the development of a national program of downtime. Until then, it is hoped that the observations from this report will initiate discussions across early adaptors, guide decision making, and promote change across systems owned and operated by those who are already convinced by these data.
启示 Implications
• 在本研究条件下，基本清洁程序可防止人员和污染物(靴子和工作服)对PRRSV和Mhyo的机械传播。
Under the conditions of this study, mechanical spread of PRRSV and Mhyo by personnel and fomites (boots and coveralls) is prevented by basic sanitation procedures.
• 根据这些观察，不需要通过延长隔离时间来减少人员和机械污染物传播这两种病原体的风险。
On the basis of these observations, extended downtime periods are not required to reduce the risk of mechanical spread of these two pathogens by personnel and fomites.
• 在进行进一步研究之前，不应将这些结果推广到其他病原体，如猪圆环病毒2型或猪流感病毒。
These results should not be extrapolated across other pathogens such as porcine circovirus type 2 or swine influenza virus until further research can be conducted.
猪场实用！母猪发情鉴定的方法及注
母猪如何养殖？揭秘母猪养殖的秘密
猪场如何消毒，怎么让你的付出达到
炎炎夏日，送上猪舍省钱、降温、效
提高仔猪存活率不难，就做好这5点！
脚下有泥，心中有光 | 牧原农艺师
携手共赢，友谊长存：江西正邦作物保
国新办举行7月份国民经济运行情况新
农业农村部就2022年“三夏”生产形势