譯者的話：

人員入場隔離期多長時間合適？4晚、7天、14天？在即將來臨的低價低利潤養(yǎng)殖時期，任何成本的浪費或者冗余都會降低企業(yè)的競爭力，隔離期的長短不僅僅是勞務(wù)成本的增加，相應(yīng)隔離設(shè)施、檢測、物流成本也會增加。本實驗在長達(dá)近四年觀察監(jiān)測期中，多角度的對比不同生物安全措施/等級和隔離期對藍(lán)耳?。绹咧虏⌒远局辏┖蜌獯鞑サ挠绊懀?4-16個小時的淋浴更衣?lián)Q鞋+隔離是可以阻斷藍(lán)耳病毒和氣喘病的傳播的，累計45分鐘的淋浴更衣?lián)Q鞋隔離期在短期對比實驗中也顯示了有效性。此實驗結(jié)果是對既往較長的隔離期的一種挑戰(zhàn)，也是對包括非瘟在內(nèi)其他疫病的隔離期的設(shè)定的一種思考，拋玉引玉，期待著國內(nèi)有類似的研究信息共享。

同行評審

一晚的隔離時間可以防止豬繁殖和呼吸綜合癥病毒和豬肺炎支原體通過人員和污染物(靴子和工作服)傳播（上）

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 1

作者 Authors

Andrea Pitkin, MS

Satoshi Otake, DVM, PhD

Scott Dee, DVM, MS, PhD, Diplomate ACVM

概要 Summary

本文總結(jié)了4年(1438天)的觀察記錄，關(guān)于一晚的隔離時間對防止豬繁殖和呼吸綜合征病毒和豬肺炎支原體通過人員和污染物在豬群間機(jī)械傳播的能力。

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.

關(guān)鍵詞：豬，豬繁殖和呼吸綜合癥，隔離，人員，污染物

Keywords: swine, porcine reproductive and respiratory syndrome, downtime, personnel, fomites

長時間限制與其他豬群接觸過的人員進(jìn)入養(yǎng)豬場的做法(隔離)是全球養(yǎng)豬業(yè)中一個極具爭議的話題。多年來，盡管缺乏數(shù)據(jù)來支持這些隔離時間的科學(xué)性，但為了減少人員將病原體引入農(nóng)場的風(fēng)險，豬場都在實施從48小時到96小時不等的隔離時間。在文獻(xiàn)中，Sellers^[1]等人調(diào)查了人們接觸感染豬只后攜帶口蹄疫病毒的能力。結(jié)果表明，在暴露后28小時，一個人的鼻拭子陽性，但在暴露后48小時，沒有出現(xiàn)陽性。然而，嘗試復(fù)制這些結(jié)果的并沒有成功^[2]。同樣，Amass^[3]等人報道，在接觸感染豬5和24小時后，可分別從指甲沖洗和鼻拭子重獲豬繁殖和呼吸綜合征病毒(PRRSV) 的RNA。然而，在這些樣本中PRRSV的生存能力沒有被證實，也沒有觀察到傳染陰性哨兵豬。最后，Otake^[4]等人從接觸感染動物的人員的手、靴子和工作服中重獲了傳染性的PRRSV病毒，并證明傳染給了陰性哨兵豬。然而，這項研究還表明，在不考慮隔離的情況下，基本的衛(wèi)生干預(yù)措施，如淋浴和更換衣服和鞋類，可以防止PRRSV的機(jī)械傳播^[4]?？傊?，這些數(shù)據(jù)對延長隔離時間的價值提出了挑戰(zhàn)；因此，為了更好地理解這一風(fēng)險，我們總結(jié)了關(guān)于一晚的隔離時間防止豬繁殖和呼吸綜合癥病毒(PRRSV)和豬肺炎支原體(Mhyo)通過人員和污染物(靴子和工作服)從感染豬群向易感豬群傳播能力的觀察。

The practice of restricting personnel entry to swine farms for extended periods of time following contact with other pigs (downtime) is a highly controversial subject throughout the global swine industry. For many years, downtime periods ranging from 48 to 96 hours have been enforced to reduce the risk of pathogen introduction to farms by personnel, despite a lack of data supporting these periods of time. In the literature, Sellers et al1 investigated the ability of people to harbor foot-and- mouth disease virus following exposure to infected swine. Results indicated the presence of one positive nasal swab from one person 28 hours post exposure, but not at 48 hours post exposure; however, attempts to replicate these results have not been successful.2 Likewise, Amass et al3 reported the recovery of porcine reproductive and respiratory syndrome virus (PRRSV) RNA from fingernail rinses and nasal swabs 5 and 24 hours, respectively, following contact with infected pigs; however, the viability of PRRSV in these samples was not confirmed and transmission to naive sentinels was not observed. Finally, Otake et al4 recovered infectious PRRSV from the hands, boots, and coveralls of personnel following contact with infected animals and demonstrated transmission to naive sentinels. However, this study also demonstrated that basic sanitary interventions such as showering and changing clothing and footwear could pre- vent mechanical spread of PRRSV, irrespective of downtime.4 Collectively, these data challenge the value of extended downtime periods; therefore, to better understand this risk, we summarized observations regarding the ability of a 1-night downtime period to prevent the mechanical spread of PRRSV and Mycoplasma hyopneumoniae (Mhyo) from infected to susceptible populations by personnel and fomites.

材料和方法

Materials and methods

設(shè)施 Facilities

我們的觀察記錄與一項為期4年（2006-2010）的PRRSV和Mhyo在豬疾病凈化中心生產(chǎn)區(qū)域模型(明尼蘇達(dá)州圣保羅)進(jìn)行的區(qū)域傳播和生物安全性評估相結(jié)合^[5,6]。在本報告中，我們將重點關(guān)注在為期4年的區(qū)域傳播和生物安全項目中使用的三個設(shè)施的活動：豬群本身、場內(nèi)人員住所和高級別生物安全的豬舍(圖1)。

Our observations were recorded in conjunction with a 4-year evaluation of area spread and biosecurity of PRRSV and Mhyo conducted at the Swine Disease Eradication Center Production Region Model (St Paul, Minnesota) over the period 2006-2010.5,6 For the purpose of this report, we will focus on activities that occurred in three facilities that were utilized throughout the 4-year area spread and biosecurity project: the source population, the on-site residence, and the high-level biosecurity building (Figure 1).

該豬群為300頭25- 120公斤的豬只，這些豬只在1 - 4年內(nèi)試驗接種了PRRSV MN-184，在2 - 4內(nèi)年試驗接種了Mhyo菌株232^[5,6]。這是一個持續(xù)流通的豬群，因此，在整個四年的研究期間，該設(shè)施從未被清空。新到的豬只，大約6到8周齡，每2到4周進(jìn)入該設(shè)施，這取決于當(dāng)前研究的實驗設(shè)計^[5,6]。新進(jìn)豬只被放置在與現(xiàn)有豬群相鄰的圍欄中，允許鼻子對鼻子的接觸，使得病原體從被感染的動物傳播到未感染的動物。在整個研究過程中，記錄了豬群呼吸系統(tǒng)疾病的臨床癥狀以及PRRSV和Mhyo在豬群內(nèi)的排毒情況，發(fā)現(xiàn)年死亡率為10% - 12% ^[5,6]。

 The source population contained three hundred 25- to 120-kg pigs that had been experimentally inoculated with PRRSV MN-184 during years 1 to 4 and with Mhyo strain 232 during years 2 to 4.5,6 This was a continuous-flow population; therefore, the facility was never emptied during the entire 4-year study. New animals, approximately 6 to 8 weeks in age, entered this facility every 2 to 4 weeks depending on the experimental design of the current study.5,6 New animals were placed in pens adjacent to existing animals, allowing for nose-to-nose contact and circulation of pathogens from infected to naive animals. Throughout the course of the study, clinical signs of respiratory disease and shedding of PRRSV and Mhyo within the population were documented, and a 10% to 12% annual mortality was recorded.5,6

現(xiàn)場住所是豬病凈化中心的一所房子，作為工作人員的淋浴進(jìn)出設(shè)施，以及一處農(nóng)場專用衣物的洗滌和鞋類的消毒場所。

The on-site residence was a house on the Swine Disease Eradication Center premises that served as a shower-in, shower-out facility for personnel and a site for washing farm-specific clothing and disinfection of farm-specific footwear.

最后，這個高級生物安全設(shè)施有10只豬，它們在整個項目期間無PRRSV和Mhyo感染。這一設(shè)施使用的是豬群全進(jìn)全出原則；因此，第1年每2周一次(1年共26批豬)，第2 - 4年每4周一次(2 - 4年共39批豬)都有新一批豬進(jìn)入。該設(shè)施的生物安全計劃包括一系列經(jīng)過科學(xué)驗證的干預(yù)措施，針對PRRSV和Mhyo的所有直接和間接傳播途徑，包括一個空氣過濾系統(tǒng)，旨在防止引入受PRRSV和Mhyo污染的生物氣溶膠^[5-7]。

Finally, the high-level biosecurity building was a swine facility which contained 10 animals naive for PRRSV and Mhyo throughout the project. This facility was operated using all-in, all-out pig-flow principles; therefore, new batches of animals entered every 2 weeks during year 1 (a total of 26 batches of pigs during year 1) and every 4 weeks during years 2 to 4 (a total of 39 batches of pigs across years 2 to 4). The biosecurity program for this facility consisted of a series of scientifically validated interventions for all direct and indirect routes of PRRSV and Mhyo transmission, including an air filtration system designed to prevent introduction of PRRSV- and Mhyo-contaminated bioaerosols.5-7

時間周期和活動事項

Time period and activities

同樣，本著本報告的目的，我們將重點關(guān)注在為期4年的區(qū)域傳播和生物安全項目中每天發(fā)生的三個具體事項周期：污染期、清潔和隔離期以及監(jiān)測期。污染期大約每天發(fā)生在中央標(biāo)準(zhǔn)時間(CST)下午2點到4點之間。這段時間的目的是讓研究人員接觸受PRRSV和Mhyo感染的動物。在污染期間，工作人員進(jìn)入該設(shè)施的所有11個大欄內(nèi)，在那里他們飼喂動物、清理大欄地板、治療病豬、移走死豬并完成必要的維修工作。在一個常規(guī)的工作日里，會有一到兩個人進(jìn)入每個設(shè)施。每個月，工作人員還標(biāo)記并銷售育肥豬，并對豬群進(jìn)行抽樣，以檢測PRRSV和Mhyo的狀態(tài)。每天污染期結(jié)束后，工作人員離開設(shè)施，并開始清潔和隔離期。

Again, for the purpose of this report, we will focus on three specific activity periods that occurred daily throughout the 4-year area spread and biosecurity project: the contamination period, the sanitation and downtime period, and the monitoring period. The contamination period occurred from approximately 2 pm to 4 pm Central Standard Time (CST) each day. The purpose of this period was to expose study personnel to PRRSV- and Mhyo-infected animals. During the contamination period, personnel entered all 11 pens in the source-population facility, where they fed animals, cleaned pen floors, treated sick pigs, removed dead animals, and completed necessary repair work. On an average working day, one or two people would have entered each facility. On a monthly basis, personnel also marketed finished animals and sampled the population to monitor its PRRSV and Mhyo status. Following completion of the contamination period each day, personnel left the facility and initiated the sanitation and downtime period.

清潔和隔離時間在污染期之后立即開始，大約從下午4點持續(xù)到第二天上午6點，中央標(biāo)準(zhǔn)時間(CST)。這個時期的目的是中和污染期的影響。在此期間，工作人員從豬場去往住所，在那里他們脫掉農(nóng)場的衣服和鞋，洗澡，穿上自己的衣服和鞋子，并從當(dāng)天下午大約4點到第二天早上大約6點避免與豬接觸。用7%戊二醛和26%季銨鹽(辛力加；國際保護(hù)協(xié)會，亞特蘭大，喬治亞)對農(nóng)用衣物和鞋類進(jìn)行消毒。第二天中央標(biāo)準(zhǔn)時間(CST)大約早上5:30，工作人員再次洗澡，穿上干凈的農(nóng)場專用服裝衣物和鞋子，進(jìn)入高生物安全級別的設(shè)施內(nèi)，開始監(jiān)測階段。

The sanitation and downtime period occurred immediately after the contamination period and ran from approximately 4 pm to 6 am CST. The purpose of this period was to neutralize the effects of the contamination period. During this period, personnel moved from the source population to the on-site residence where they removed farm clothing and footwear, took a shower, donned street clothing and footwear, and refrained from pig contact from approximately 4 pm that afternoon until approximately 6 am the next morning. Farm-specific clothing was washed and footwear was disinfected using 7% glutaraldehyde and 26% quaternary ammonium chloride (Synergize; Preserve International, Atlanta, Georgia). At approximately 5:30 am CST on the following day, personnel took another shower, donned clean farm-specific clothing and footwear, and entered the high-level biosecurity building for initiation of the monitoring period.

 監(jiān)測期是與該報告有關(guān)的第三個也是最后一個事項期，監(jiān)測時間為每天中央標(biāo)準(zhǔn)時間(CST)上午6時至8時，在該高生物安全設(shè)施內(nèi)進(jìn)行。這個時期的目的是衡量在清潔和隔離期間所采用的做法的有效性。具體來說是測量兩個結(jié)果：對人員進(jìn)行PRRSV和Mhyo檢測，以及檢測設(shè)施中飼養(yǎng)的哨兵豬的PRRSV-Mhyo狀態(tài)。清潔和隔離時間結(jié)束后，工作人員立即從住所前往距離約100米的高級別生物安全設(shè)施。進(jìn)入設(shè)施專用接待室后，立刻進(jìn)行拭子檢查，以確定人員、衣物和鞋類上是否存在PRRSV RNA或Mhyo DNA。為了收集樣本，滌綸拭子(Fisher Scientific, Hanover Park, Illinois)浸入含有3%胎牛血清的微量培養(yǎng)基(MEM)中(Difco, Detroit, Michigan)，并以“之”字型在每個人的頭部、面部、頸部、軀干、手、手臂和腿上滑動擦拭。然后將拭子保存在-20℃的MEM中，直到收集后24 - 48小時進(jìn)行實驗室分析，以保持病毒完整性并最大化檢測敏感性。取樣后，穿上設(shè)施專用的靴子、工作服和手套，并用7%的戊二醛和26%的季銨鹽對靴子進(jìn)行消毒。工作人員隨后進(jìn)入豬群內(nèi)，喂豬，打掃圍欄。此外，每周對這10頭豬進(jìn)行健康診斷評估，包括對呼吸道疾病的臨床癥狀進(jìn)行目視觀察，對所有10頭豬進(jìn)行血液檢測和鼻腔擦拭。在采集之后，明尼蘇達(dá)大學(xué)獸醫(yī)診斷實驗室(明尼蘇達(dá)圣保羅MN VDL)通過聚合酶鏈反應(yīng)(PCR)對人員、污染物和動物的所有樣本進(jìn)行了PRRSV RNA和Mhyo DNA的檢測^[8,9]。

The monitoring period was the third and final period pertaining to this report and occurred in the high-biosecurity building from approximately 6 am to 8 am CST each day. The purpose of this period was to measure the efficacy of the practices utilized during the sanitation and downtime period. Specifically, two outcomes were measured: detection of PRRSV and Mhyo on personnel and the PRRSV-Mhyo status of sentinel animals housed in the facility. Upon completion of the sanitation and downtime period, personnel moved immediately from the on-site residence to the high-level biosecurity building, a distance of approximately 100 m. Upon entry into the facility-specific anteroom, a swabbing protocol, designed to determine if PRRSV RNA or Mhyo DNA was present on personnel, clothing, and footwear, was conducted.5,6 For collection of samples, Dacron swabs (Fisher Scientific, Hanover Park, Illinois) were immersed in minimal essential medium (MEM) supplemented with 3% fetal calf serum (Difco, Detroit, Michigan) and swiped using a zigzag pattern across each person’s head, face, neck, torso, hands, arms, and legs. Swabs were then stored in MEM at -20°C to maintain viral integrity and maximize testing sensitivity until laboratory analysis could be conducted 24 to 48 hours post collection. Following sampling, facility-specific boots, coveralls, and gloves were donned and boots were disinfected using 7% glutaraldehyde and 26% quaternary ammonium chloride. Personnel then entered the animal air space, fed pigs, and cleaned pens. In addition, on a weekly basis, a diagnostic assessment of the health of this 10-pig population was conducted, involving visual observation of clinical signs of respiratory disease and blood testing and nasal swabbing of all 10 pigs. Immediately following collection, all samples from personnel, fomites, and animals were tested for PRRSV RNA and Mhyo DNA by polymerase chain reaction (PCR) at the University of Minnesota Veterinary Diagnostic Laboratory (MN VDL, St Paul, Minnesota).8,9