譯者的話(huà)：

人員入場(chǎng)隔離期多長(zhǎng)時(shí)間合適？4晚、7天、14天？在即將來(lái)臨的低價(jià)低利潤(rùn)養(yǎng)殖時(shí)期，任何成本的浪費(fèi)或者冗余都會(huì)降低企業(yè)的競(jìng)爭(zhēng)力，隔離期的長(zhǎng)短不僅僅是勞務(wù)成本的增加，相應(yīng)隔離設(shè)施、檢測(cè)、物流成本也會(huì)增加。本實(shí)驗(yàn)在長(zhǎng)達(dá)近四年觀(guān)察監(jiān)測(cè)期中，多角度的對(duì)比不同生物安全措施/等級(jí)和隔離期對(duì)藍(lán)耳?。绹?guó)高致病性毒株）和氣喘病傳播的影響：14-16個(gè)小時(shí)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(jì)45分鐘的淋浴更衣?lián)Q鞋隔離期在短期對(duì)比實(shí)驗(yàn)中也顯示了有效性。此實(shí)驗(yàn)結(jié)果是對(duì)既往較長(zhǎng)的隔離期的一種挑戰(zhàn)，也是對(duì)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(guó)內(nèi)有類(lèi)似的研究信息共享。

同行評(píng)審

一晚的隔離時(shí)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(guò)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(guān)察記錄，關(guān)于一晚的隔離時(shí)間對(duì)防止豬繁殖和呼吸綜合征病毒和豬肺炎支原體通過(guò)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(zhǎng)時(shí)間限制與其他豬群接觸過(guò)的人員進(jìn)入養(yǎng)豬場(chǎng)的做法(隔離)是全球養(yǎng)豬業(yè)中一個(gè)極具爭(zhēng)議的話(huà)題。多年來(lái)，盡管缺乏數(shù)據(jù)來(lái)支持這些隔離時(shí)間的科學(xué)性，但為了減少人員將病原體引入農(nóng)場(chǎng)的風(fēng)險(xiǎn)，豬場(chǎng)都在實(shí)施從48小時(shí)到96小時(shí)不等的隔離時(shí)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(shí)，一個(gè)人的鼻拭子陽(yáng)性，但在暴露后48小時(shí)，沒(méi)有出現(xiàn)陽(yáng)性。然而，嘗試復(fù)制這些結(jié)果的并沒(méi)有成功^[2]。同樣，Amass^[3]等人報(bào)道，在接觸感染豬5和24小時(shí)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(méi)有被證實(shí)，也沒(méi)有觀(guān)察到傳染陰性哨兵豬。最后，Otake^[4]等人從接觸感染動(dòng)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(xiàng)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(lèi)，可以防止PRRSV的機(jī)械傳播^[4]。總之，這些數(shù)據(jù)對(duì)延長(zhǎng)隔離時(shí)間的價(jià)值提出了挑戰(zhàn)；因此，為了更好地理解這一風(fēng)險(xiǎn)，我們總結(jié)了關(guān)于一晚的隔離時(shí)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(guò)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(guān)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(guān)察記錄與一項(xiàng)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(píng)估相結(jié)合^[5,6]。在本報(bào)告中，我們將重點(diǎn)關(guān)注在為期4年的區(qū)域傳播和生物安全項(xiàng)目中使用的三個(gè)設(shè)施的活動(dòng)：豬群本身、場(chǎng)內(nèi)人員住所和高級(jí)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(yàn)接種了PRRSV MN-184，在2 - 4內(nèi)年試驗(yàn)接種了Mhyo菌株232^[5,6]。這是一個(gè)持續(xù)流通的豬群，因此，在整個(gè)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(shí)驗(yàn)設(shè)計(jì)^[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(duì)鼻子的接觸，使得病原體從被感染的動(dòng)物傳播到未感染的動(dòng)物。在整個(gè)研究過(guò)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(chǎng)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(chǎng)專(zhuān)用衣物的洗滌和鞋類(lèi)的消毒場(chǎng)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(gè)高級(jí)生物安全設(shè)施有10只豬，它們?cè)谡麄€(gè)項(xiàng)目期間無(wú)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(jì)劃包括一系列經(jīng)過(guò)科學(xué)驗(yàn)證的干預(yù)措施，針對(duì)PRRSV和Mhyo的所有直接和間接傳播途徑，包括一個(gè)空氣過(guò)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(shí)間周期和活動(dòng)事項(xiàng)

Time period and activities

同樣，本著本報(bào)告的目的，我們將重點(diǎn)關(guān)注在為期4年的區(qū)域傳播和生物安全項(xiàng)目中每天發(fā)生的三個(gè)具體事項(xiàng)周期：污染期、清潔和隔離期以及監(jiān)測(cè)期。污染期大約每天發(fā)生在中央標(biāo)準(zhǔn)時(shí)間(CST)下午2點(diǎn)到4點(diǎn)之間。這段時(shí)間的目的是讓研究人員接觸受PRRSV和Mhyo感染的動(dòng)物。在污染期間，工作人員進(jìn)入該設(shè)施的所有11個(gè)大欄內(nèi)，在那里他們飼喂動(dòng)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(gè)常規(guī)的工作日里，會(huì)有一到兩個(gè)人進(jìn)入每個(gè)設(shè)施。每個(gè)月，工作人員還標(biāo)記并銷(xiāo)售育肥豬，并對(duì)豬群進(jìn)行抽樣，以檢測(cè)PRRSV和Mhyo的狀態(tài)。每天污染期結(jié)束后，工作人員離開(kāi)設(shè)施，并開(kāi)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(shí)間在污染期之后立即開(kāi)始，大約從下午4點(diǎn)持續(xù)到第二天上午6點(diǎn)，中央標(biāo)準(zhǔn)時(shí)間(CST)。這個(gè)時(shí)期的目的是中和污染期的影響。在此期間，工作人員從豬場(chǎng)去往住所，在那里他們脫掉農(nóng)場(chǎng)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(diǎn)到第二天早上大約6點(diǎn)避免與豬接觸。用7%戊二醛和26%季銨鹽(辛力加；國(guó)際保護(hù)協(xié)會(huì)，亞特蘭大，喬治亞)對(duì)農(nóng)用衣物和鞋類(lèi)進(jìn)行消毒。第二天中央標(biāo)準(zhǔn)時(shí)間(CST)大約早上5:30，工作人員再次洗澡，穿上干凈的農(nóng)場(chǎng)專(zhuān)用服裝衣物和鞋子，進(jìn)入高生物安全級(jí)別的設(shè)施內(nèi)，開(kāi)始監(jiān)測(cè)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(cè)期是與該報(bào)告有關(guān)的第三個(gè)也是最后一個(gè)事項(xiàng)期，監(jiān)測(cè)時(shí)間為每天中央標(biāo)準(zhǔn)時(shí)間(CST)上午6時(shí)至8時(shí)，在該高生物安全設(shè)施內(nèi)進(jìn)行。這個(gè)時(shí)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(lái)說(shuō)是測(cè)量?jī)蓚€(gè)結(jié)果：對(duì)人員進(jìn)行PRRSV和Mhyo檢測(cè)，以及檢測(cè)設(shè)施中飼養(yǎng)的哨兵豬的PRRSV-Mhyo狀態(tài)。清潔和隔離時(shí)間結(jié)束后，工作人員立即從住所前往距離約100米的高級(jí)別生物安全設(shè)施。進(jìn)入設(shè)施專(zhuān)用接待室后，立刻進(jìn)行拭子檢查，以確定人員、衣物和鞋類(lèi)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(gè)人的頭部、面部、頸部、軀干、手、手臂和腿上滑動(dòng)擦拭。然后將拭子保存在-20℃的MEM中，直到收集后24 - 48小時(shí)進(jìn)行實(shí)驗(yàn)室分析，以保持病毒完整性并最大化檢測(cè)敏感性。取樣后，穿上設(shè)施專(zhuān)用的靴子、工作服和手套，并用7%的戊二醛和26%的季銨鹽對(duì)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(duì)這10頭豬進(jìn)行健康診斷評(píng)估，包括對(duì)呼吸道疾病的臨床癥狀進(jìn)行目視觀(guān)察，對(duì)所有10頭豬進(jìn)行血液檢測(cè)和鼻腔擦拭。在采集之后，明尼蘇達(dá)大學(xué)獸醫(yī)診斷實(shí)驗(yàn)室(明尼蘇達(dá)圣保羅MN VDL)通過(guò)聚合酶鏈反應(yīng)(PCR)對(duì)人員、污染物和動(dòng)物的所有樣本進(jìn)行了PRRSV RNA和Mhyo DNA的檢測(cè)^[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