2017母猪群中PEDv的感染管理：控制或根除

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
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感染后周数
Total company-Seaboard 公司全部
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
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 2nd 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。
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
“Classic” PED 典型的猪流行性腹 泻病
• 相对基线的断奶百分比 • • • n = 86 herds 86个猪群 Avg TTBP = 7.4 wks 95% CI = 1.7-13 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
– 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
– 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%。
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
Seaboard Farms 西宝德猪场
– 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
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 • Exposure 感染 • Control inoculum (virus amplified on CD piglets) 控制接种（病毒在Cd仔猪上被 放大） • Systematic euthanasia 系统性安乐死 • Hygiene 卫生
• Immunity 免疫
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
Eradication Vs Control 根除与控制
• Eradication of the PED virus in the farm 猪场中PED的根除 • Protect from introduction of virus从病毒可能引入的方面开始防护
– Easily done 很容易做到 – 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
– 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 – White wash all farrowing houses 对所有的产房进行石灰洗刷 – 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
•Biblioteka BaiduHerd 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
• 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
– 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 – 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
• 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