Managing PEDv infection in sow herd: Control or Eradication? 母猪群中 PEDv 的感染管理 : 控制或根除? Luc Dufresne DVM Director of Health Assurance 卢克迪弗雷纳, 兽医专家健康保障主

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1 Managing PEDv infection in sow herd: Control or Eradication? 母猪群中 PEDv 的感染管理 : 控制或根除? Luc Dufresne DVM Director of Health Assurance 卢克迪弗雷纳, 兽医专家健康保障主任

2 Seaboard Farms 西宝德猪场 Total 78 sow farms 336,000 sows 78 个母猪场共 336,000 头母猪 All were initially infected during outbreak of 2013 and 2014 在 2013 至 2014 病毒爆发期间, 所有猪场均出现感染疫情 Currently only 1 farm is receiving naïve gilts 目前仅一家猪场接收未感染过病毒的后备母猪 All other farms are receiving gilts that have been exposed to PEDv but are not shedding at the time of transfer 其它猪场接收的后备母猪均有 PEDv 的感染史, 但在转运过程中未发现有排毒的现象

3 Load close homogenize phase 1: Based on TGE protocol 第一阶段装猪封群均化处理 : 基于 TGE 策略 Load-close-homogenize program similar to TGE. 施行与 TGE 类似的装猪, 装猪封群均化过程 Wean all piglets 10 days of age and older into an off-site facility. 大于 10 天的仔猪断乳后转到场外 Enter gilt to induce a minimum of 12 week closure of the farm 引进的后备母猪需进行至少 12 周的隔离 Start immediately exposing sows and gilts 2 to 5 weeks pre-farrow with scours 用腹泻物给分娩前 2 到 5 周的母猪和后备即刻感染 The purpose of tissue feedback is to get all animals onsite uniformly exposed to the virus as quickly as possible 进行组织返饲的目的是尽快使猪只一致性感染病毒 Whole herd feedback is performed a minimum of 3 times in a two week period. 全群返饲需在 2 周内至少执行 3 次 Ratio of 1 intestine to 10 sows for each feedback. 每次返饲用一副肠组织处理 10 头母猪 The number of sows recorded to show some clinical signs varied greatly from less than 40% up to 90%. 记录显示产生临床症状的母猪数量变化明显, 由不足 40% 升至 90%

4 Immunity 免疫 In our experience herds return to normal (pre-break) pre-wean mortality 5 to 6 weeks after exposure. 根据我们的经验, 畜群在感染后 5 到 6 周恢复到断乳前正常死亡率 Using the above protocol, about 70% of herds pre-wean mortality remains normal for an extended period. 使用上述策略, 约 70% 的畜群断乳前死亡率在很长一段时间内保持正常 Unfortunately, the remainder of herds experience varying degrees of clinical relapse. 不幸的是, 其余的畜群经历了不同程度的临床复发 Herds that broke during the 2 nd wave of infection that occurred during winter never returned to normal and moved from acute to chronic infection. 在冬季被第二波病毒爆发所感染的畜群, 不会再恢复到正常状态, 而是一个由急性感染过渡到慢性感染的过程

5 Classic PED 典型的猪流行性腹泻病 n = 86 herds 86 个猪群相对基线的断奶百分比 Avg TTBP = 7.4 wks 95% CI = 恢复到基准生产所需时间 =7.4 周 Avg lost 2,501/1000 sows 95% CI = 64-4,939 平均损失,2501/ 每千头母猪感染后周数

6 Total company-seaboard 公司全部

7 Endemic sow herd 地方流行发病母猪畜群 Failure to induce complete herd protective immunity? Not likely 未能引起完全的群体保护免疫? 不太可能 Waning herd immunity combine with a higher than normal viral challenge (Main cause) 群体免疫力减弱结合高毒价病毒感染 ( 主要原因 ) Additional risk factor 其他危险因素 No or limited herd closure 没有或仅进行有限的畜群封闭 Gilt exposure on-site or entering shedding gilts 场内后备母猪感染或引入正在排毒的后备母猪 Size of the farm (>5000 sows) 农场大小 (>5000 头母猪 ) Colder temperatures 低温 Walkthrough farrowing house 通透产房

8 Lessons learned 得到的经验 It is not TGE! 这不是 TGE! Virus exposure is the easy part 病毒感染很容易 Virus replicate at very high level especially in piglet 病毒在仔猪身上的复制水平尤为高 Do not allow the virus to replicate more than necessary 不允许病毒进行超常的复制 Virus is highly infectious 病毒感染性很高 Hygiene need to reach new standard 卫生需要达到新的标准 Minimize movement of animals and people 尽量减少动物和人员移动 Herd Immunity is as high as it going to get 3 to 4 week after exposure 畜群的免疫效果在病毒接种后的 3 到 4 周达到最高 Herd may be non clinical but virus is still present 畜群可能未表现出临床症状但病毒依然存在 Time is not on your side! 时间不是你来决定的! 6 to 12 week after the initial exposure is the time to eliminate the virus from the environment 病毒在初次感染后的 6 至 12 周后会逐渐从环境中清除

9 New protocol 新流程 As soon as herd is diagnosed positive for PEDv 一旦畜群被确诊为 PEDV 阳性 All piglet 7+ days are wean offsite 所有大于 7 天的仔猪需场外断乳 All remaining piglet are Euthanized immediately 所有其余的仔猪立即进行安乐死 Exposure 感染 Control inoculum (virus amplified on CD piglets) 控制接种 ( 病毒在 Cd 仔猪上被放大 ) Administer through backpack sprayer 通过背包式喷雾器处理 3 administration over a week 每周进行 3 次处理 Systematic euthanasia 系统性安乐死 All piglet are euthanized at birth for 21 days 所有在 21 天内出生的小猪均被执行安乐死 Hygiene 卫生 White wash all farrowing houses 对所有的产房进行石灰洗刷 Immunity 免疫 Administer killed ped Vaccine to all sows and gilts 1 week pre-farrow 给所有产前一周的母猪和后备母猪注射 PED 灭活疫苗

10 New protocol 新流程 Results 结果 14 herds were exposed using the new protocol 用新流程给 14 个猪群感染 14 out of 14 were back to normal piglet output 6 weeks after exposure 所有的 14 个猪群在感染后 6 周恢复到正常的猪仔产量 12 out of 14 herd produce piglet that were negative to PED on first group of piglet that where not euthanized 经检测, 在 14 个猪群中, 有 12 个猪群的第一批未安乐死仔猪为 PED 阴性 14 out of 14 were producing negative piglet 8 week after initial exposure 经检测,14 个畜群在初次感染 8 周后生产的所有小猪均为 PED 阴性 None of the 14 farms experience re-break 所有 14 个农场都没有出现疫情的复发

12 Eradication Vs Control 根除与控制 Eradication of the PED virus in the farm 猪场中 PED 的根除 Easily done 很容易做到 Protect from introduction of virus 从病毒可能引入的方面开始防护 Difficult in the panhandle of Oklahoma 在俄克拉荷马州的狭长地带比较空难 Reintroduction of the virus in finisher from slaughter movement 和屠宰厂之间的活动导致病毒的重新进入育肥舍 Virus then move easily from site to site on fecal dust 病毒借助粪便灰尘很容易从一个地方转移到另一个地方 We believe we will not be able to keep sow farm naïve until we can stop recirculation in finisher in our area 我们相信, 直到我们区域的育肥场区病毒的循环, 我们才能保持母猪场不受病毒侵害 We decide to control the disease by maintaining an immune sow population 我们尽力维持有免疫力的母猪群继而控制疾病 The goal is to consistently produce a PED negative piglet from a PED immune non shedding herd 我们的目标是从对 PED 有免疫并不排毒的畜群中持续地生产 PED 阴性仔猪

13 Gilt Exposure to PED 后备母猪的 PED 感染 Maintaining herd immunity appears to be the best solution until we understand better the virus or better tools are available to control or eradicate the disease 在我们更好地了解病毒或有更可行的控制和根除方案前, 维持畜群免疫力是目前最好的解决方案 Goal is having an immune population that produce negative piglet at weaning 目标是让免疫畜群生产阴性的断奶仔猪 Gilt acclimatization 后备母猪的驯化 Insure homogenous gilt exposure to PED virus 确保后备母猪均匀感染 PED 病毒 Insure gilts have time to develop immunity and stop shedding before they are introduced into the sow farm 确保在引进母猪场前, 后备母猪有时间产生免疫力并停止排毒

14 Gilt PED Exposure 后备母猪 PED 感染 Gilts exposed for the 1 st time at week of age 在周时, 后备母猪第一次感染 1 time spray in nose/mouth 在鼻腔 / 口喷雾一次 1 time thru waterline 通过饮水管 1 次 Gilts exposed for a 2 nd time at 18 to 24 week of age 在周时, 后备母猪第二次感染 1 time thru waterline only 通过饮水管 1 次 4 week before shipment to cool-off site 被移送至静缓厂址前 4 周

15 Gilt Exposure 后备母猪 PED 感染 Gilts are moved to cool-off site for 6 to 10 weeks 后备母猪转移到静缓厂址饲养 6 至 10 周 Oral fluids are collected and tested for PED 1 week before shipment and every week animal are shipping from the barn/room 在移送前 1 周, 收集口腔液体并检测 PED 并保持每周都有从猪舍输送来的动物 If scour is detected at anytime around shipment 如果在运输中检测到腹泻 Movement is cancelled 取消运输 Scour is tested immediately for PED by PCR 立即通过 PCR 检测腹泻物中是否存在 PED

16 Dealing with Endemic/Re-breaking sow herd 处理地方流行的 / 反复爆发疫情的母猪畜群 Increase Immunity 增强免疫力 Vaccine will help 疫苗会起作用 Virus exposure may be necessary especially on gilts 病毒感染可能是必须的, 尤其是对后备母猪 Reduce pressure of infection 减少感染压力 Bubble depop and unidirectional pig flow 部分清群和猪群的单向流动 Through early weaning or off site farrowing 通过早期断乳或场外分娩 High hygiene and people movement are key and hard to control 高卫生标准和人群移动是解决问题的重点, 很难控制 Reduce virus replication 减少病毒复制 Euthanasia of at-risk litter 给高风险窝安乐死 Gilt Litter? 后备母猪窝仔? Scouring Litter? 腹泻的窝仔?

17 Evaluate PED shedding following live virus inoculation of gestating gilts 评估接种活病毒的妊娠后备母猪的 PED 排毒 Objective- 目标 - o Determine immunologic response and duration of shedding following live virus inoculation of gestating gilts previously inoculated during acclimation. 确定妊给在驯化时接种的娠后备母猪接种活毒后, 适应过程中的免疫反应强度和持续排毒时间 Tested 3 doses (10 6, 10 5, 10 4 viral copies per dose) 测试 3 个剂量处理稀释倍数单剂量病毒拷贝数 Ct 值单剂量病毒拷贝数 *equation without extraction factor (received 12/2/13); **equation with extraction factor (received 5/18/15)

18 PEDv FFN Titers were higher with increasing dose of PED inoculum. PEDv FFN 效价随 PED 接种剂量的增多而升高

19 Fecal and Anorexia scores were normal (score=1) for all doses within 7 days post-inoculation. 各剂量接种 7 天后, 粪便和厌食打分均正常 ( 分数 =1)

20 Clinically relevant fecal shedding ceased between 17 and 21 days post-inoculation. 临床相关的粪便排毒在接种后第 17 到 21 天内停止 PEDv 粪便排毒接种后天数

21 Evaluate PED shedding following live virus inoculation of gestating gilts 评估接种活毒的妊娠后备母猪的 PED 排毒量 Implications- 意义 o Oral re-inoculation of gestating gilts with PEDv 对妊娠后备母猪进行口腔再次接种 PEDv Higher titers were associated with higher doses 高滴度和高剂量有关 Shedding (estimated by Ct values) was not different b/t doses on days 0, 3 and 21 post-inoculation 在接种不同剂量病毒后第 0, 3 和 21 天的母猪的排毒量 ( 根据 Ct 值评估 ) 无区别 Fecal scores returned to normal (score=1) 6 days post-inoculation for all doses 在接种不同剂量后 6 天, 粪便打分均恢复到正常 ( 分值 =1) Anorexia scores returned to normal (score=1) 7 days post-inoculation 接种后第 7 天, 厌食打分恢复到正常 ( 分值 =1) o Gestating gilts previously exposed to PEDv are positive (Ct<35) for PEDv by PCR for days post-inoculation PCR 显示, 之前接种 PEDv 的妊娠母猪在接种后天 PEDv 显示阳性 (Ct<35)

22 What to do when PED is Re-introduced 畜群再次进入 PED 时, 需要做什么? Small % of herd rebreak 少数畜群再次爆发 Infected clinical growing pig in the area is one of the major risk 该地区受感染的有临床症状的生长猪是主要的风险之一 Clinical Appearance 临床表现 Mild scour in small% of sow or small increase of scour on the piglets close to weaning age 少量的母猪出现轻度腹泻或接近断奶年龄的仔猪的腹泻情况增多 Protocol 流程 Wean all the affected room and usually go down to days of age 所有感染的猪舍断奶, 一般在天日龄 Load farrowing house with sow that are 107 to 114 days of Gestation 把妊娠 107 到 114 天繁荣母猪装进产房 Seal the farrowing house from the rest of the farm 封闭产房与猪场其他猪舍隔离 Employee bypass shower walk from outside and get dress and work only in the farrowing house 员工需绕过浴室进入并只能在产房换衣和工作 Expose all remaining sow present in the breeding and gestation (not in farrowing house) 对其余的繁殖群和妊娠的母猪进行感染 ( 不包括在产房内的母猪 )

23 What to do when PED is Re-introduced? 畜群再次引入 PED 时, 需要做什么? 17 days after exposure initiate a bubble depopulation 感染后 17 天开始进行部分清群 As a section of farrowing is completely emptied washed disinfected that section is consider clean 当一部分产房完全清空清洗消毒, 才能认为此部分产房是干净的 That section is now accessible from the rest of the farm but seal from the other Farrowing room that have not been through a complete cleaning and sanitizing protocol 这部分区域现在可以和猪场其他部分相通, 但是不要和其他的还未完全清洁和消毒的产房相通 Once all section of the farrowing have been through the farm is back to normal production (6 week protocol) 一旦所有猪场的产房恢复到正常生产 (6 周流程 ) Performance 成绩 Piglet that farrow from immune sow exposed 7 day prefarrow 分娩前 7 天接种的免疫母猪所生产的小猪 Non-clinical and negative at weaning 无临床症状且在断乳时呈阴性 Immunity appear to overcome exposure! 免疫力战胜了感染! 5 Farms have gone through that protocol did not see any loss in the farrowing house associated with PED during the protocol 采用这个流程的 5 个农场没有出现产房内和 PED 有关的损失

24 Conclusion 总结 PED initial outbreak can be easily eliminate by a rigorous protocol of loading closing the herd and exposed the herd to PEDv as soon as possible, systemic euthanasia at birth for 21 days follow by an intense cleaning and sanitizing of all the farm PED 的初次爆发可以通过严格的流程来消除, 那就是装猪封群后, 尽快让畜群感染 PEDv 疾病发生后 21 天内出生的仔猪系统的执行安乐死, 然后给猪场进行彻底的清洁和消毒

25 Conclusion 总结 The decision of eradicate the disease from the farm should be based on the risk of reintroduction of the virus 农场应该通过考虑重新引入病毒的风险来决定是否根除疾病 If control is the goal gilt exposure should be performed in a separate ideally off site facilities 如果目标是控制疾病, 后备母猪应该在单独理想的场外设施中进行免疫

26 Conclusion 总结 Reintroduction of the virus in an immune herd can be control quickly with minimum loss by : 当病毒重新引入免疫畜群中时, 其可通过以下措施快速控制并减少损失 : Wean down 提前断奶 Load farrowing and farrowing segregation 产房装猪, 产房隔离 Breeding and gestation exposure 繁殖群和妊娠期免疫 Follow 17 day later by a farrowing bubble depopulation 17 天后, 产房进行部分清群

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PEDV management and containment in production systems 养猪生产系统中流行性腹泻的管理和控制 Leman China Swine Conference October 12 2015 李曼中国大会 2015 年 10 月 12 日 Matt Allerson, DVM, PhD Holden Farms, Inc. 麦特阿勒森, 美国霍尔顿农场

Managing PEDv infection in sow herd: Control or Eradication? 母猪群中 PEDv 的感染管理 : 控制或根除? Luc Dufresne DVM Director of Health Assurance 卢克 迪弗雷纳, 兽医专家健康保障主

Managing PEDv infection in sow herd: Control or Eradication? 母猪群中 PEDv 的感染管理 : 控制或根除? Luc Dufresne DVM Director of Health Assurance 卢克迪弗雷纳, 兽医专家健康保障主