06-5. Respiratory disease 呼吸系统疾病及其它细菌性疾病_PRRS.ppt

Respiratory disease PRRS virus呼吸道疾病繁殖与呼吸障碍综合征病毒Bob Morrison DVM, MBA, PhDSwine Group University of MinnesotaSpread 传播nWithin a herd 猪群内部In-utero 112 days transmission 子宫内112天传播Nose to nose contact 鼻对鼻接触感染nBetween herds 猪群之间Direct Contact range up to 120 days after initial infection直接接触直到最初感染之后120天还可接触感染Semen shed up to 92 days, most 40 to 55 days精液92天内均可散毒，通常是在40到55天Insects mosquitoes and flies昆虫蚊子和苍蝇Mechanical vectors needles, transport机械性传播针头、运输途中Airborne field and experimental空气传播田间和试验Pathogenesis 发病机理Immunohistochemical detection of PRRSV antigen in a pulmonary intravascular macrophages 肺的血管内巨嗜细胞中PRRSV抗原的免疫组织化学检测Clinical Signs 临床症状nFarrowing: 哺乳仔猪：Sniffling, sneezing, thumping in piglets, anorexia/agalactiae in sows 仔猪流涕、打喷嚏、呼吸困难，母猪食欲减退/缺乳nNursery: 保育猪：3 weeks appear healthy 3周看似健康6 weeks - sniffling/sneezing/anorexic 6周流涕/打喷嚏/食欲减退10 weeks - poor condition, concurrent bacterial infections 10周体况不良，并发细菌感染nmeningitis, pneumonia, septicemia, arthritis 脑膜炎、肺炎、败血症、关节炎nFinishing: 育成猪：Pneumonia, mortality, poor growth rate 肺炎、死亡、生长率低Sick pig, swollen eyelids病猪，眼睑肿胀Swollen joints 关节肿胀Lymphadenopathy 淋巴结病变PRRS induced severe pneumoniaPRRS导致严重的肺炎PRRS pneumonia moderatePRRS 肺炎中度病变Mild pneumonia caused by PRRS virus challenge 人工感染PRRS病毒引起的温和的肺炎Diagnosis 诊断nClinical signs 临床症状Reproductive 繁殖Suckling pigs 哺乳仔猪Growing pigs 生长猪nSerology 血清学nVirus detection 病毒检测Seroconversion 血清抗体生成nElisa seroconvert at 9 to 13 days post infection. Antibodies persist for 4 to 10 months. ELISA感染前9到13天内血清抗体产生。抗体能持续410个月。nIFA indirect fluorescent antibody test. Detects antibodies from 7 to 9 days post infection until 4 to 5 months.IFA间接荧光抗体检测。检测感染后79天到45月的抗体。Antigen detection 抗原检测nVirus isolation 病毒分离Isolation of virus on porcine alveolar macrophages and/or Marc-145 cells. The virus must be alive.从肺泡巨嗜细胞和/或Marc-145细胞分离病毒。病毒必须是活的。nImmunohistochemistry 免疫组织化学Demonstration of virus antigen in tissue. Testing sample size is very small. 在组织中显示病毒抗原。检测所需样品量很少。nPCR polymerase chain reaction PCR聚合酶链式反应 Amplification of a conserved portion of the virus genome.扩增病毒基因的保守片断。Virus may be alive or dead. 病毒既可以是活的也可以是死的。Can be used on a variety of samples. Grams of tissues from multiple organs can be sampled 适用于各种样品。可以取多种器官的数克组织作为样品。PCR sampling PCR样本采集nPCR samples include all tissues, semen, serum, nasal swabs, snowballs, insects, mud. PCR 样品包括所有组织，有精液、血清、鼻腔拭子、棉球、昆虫、组织匀浆。nPool samples to decrease cost and increase sensitivity at group level. 混合样品可减少费用增加群体的敏感性。PCR testing of semen 精液的PCR检测nSemen Pool up to 5 individual samples per test. Do not recommend testing fully extended semen. 精液每个检测收集5个个体样品。不推荐检测完全稀释的精液。US PRRSV 美国的PRRSVEuropean PRRSV 欧洲的PRRSVPCR testing of serum 血清PCR检测n0.5 to 1ml of serum in a centrifuged red-top tube. Keep the sample cold. Send with cold pacs next day delivery.每个红盖离心管中装0.5到1ml血清。样品低温保存。用冷藏包裹的方式次日送检。nMore virus in serum than semen 血清中的病毒量较精液为多。nLonger viremia and more virus in serum from juveniles compared to adults 相较于成年猪，青年猪病毒血症持续时间较长且血清中病毒量较多。PRRSV sequencing PRRSV测序nORF (open reading frame) 5 ORF（开放性阅读框架）5 Envelope portion of the virus 病毒的囊膜部分Highly variable portion 高度可变区Involved in the immune response 与免疫应答相关Epidemiology studies流行病学研究 Not a predictor of cross protection or virulence 不能对交叉保护性或毒力进行预测Directly from positive PCR samples直接以PCR阳性样品来检测What is the same? 同源性如何？n99.5% or more similar 99.5% 或更高的同源性RespPRRSV/Ingelvac compared to its parent field strainVirus change/mutation overtime - .5 to 1% per year病毒改变/突变率每年0.5到1Considerations 考量nWere not sequencing the whole virus genome我们没有测定整个病毒基因组序列。Value of PRRSV sequencing PRRSV测序的价值nIs this the same virus or a new introduction? 它是同一个病毒或者是新的病毒？nWhere did this come from? There has to be a least a second virus to compare it to.病毒来源？应该最起码与另一种病毒比较。nHow many viruses do I have?有多少病毒株？nIf the virus is in the nursery or finisher and not the sow herd what can I do to try and keep it out.如果病毒存在于保育或育成猪群当中，而不是存在于经产母猪群当中我们应如何避免母猪群的病毒感染？nIf it is a new virus in one sow herd can flow pigs differently to prevent spreading?如果一个经产母猪群中存在一种新病毒，可通过猪分离饲养能否防止病毒传播？Control防制nGilt acclimation后备母猪驯化nVaccination 疫苗接种nSerum injection? 免疫血清注射？