某猪场猪瘟强毒、弱毒抗体水平的检测

应用猪瘟单克隆抗体纯化酶联免疫吸附试验方法，对河南某猪场47份母猪血清进行猪瘟抗体检测，有5份血清呈猪瘟强毒抗体阳性，阳性率为10.6%，猪瘟弱毒抗体阳性率为95.7%，其群体保护率为93％。在9份仔猪血清中，猪瘟强毒抗体为阴性，猪瘟弱毒抗体阳性率为22％，只有17％的群体保护率。检测结果表明：该猪场可能有猪瘟强毒感染。     

猪瘟母源抗体在仔猪体内持续时间的研究

仔猪吮吸免疫猪瘟疫苗母猪的初乳后,监测母源抗体在仔猪体内的消长规律,以探索仔猪猪瘟疫苗最佳首免日龄.试验选择3个场共12头母猪,产前136～140天进行猪瘟兔化弱毒(细胞苗)疫苗接种,4毫升/头.通过猪瘟抗体酶联免疫吸附试验(竞争性ELISA)检测其所产仔猪7、14、21、28、35和42日龄时血清中抗体水平.结果发现,3个猪场试验仔猪母源抗体下降幅度不一,甲场第28天降到最低,丙场第21天降到最低,之后其抗体水平均出现升高现象.但3个猪场之间不同日龄仔猪抗体水平差异较大.     

用MAB-ELISA对仔猪母源猪瘟抗体的试验

用猪瘟兔化弱毒苗4头份免疫后的母猪3头，分别于分娩后定期日龄采血分离24头份血清样品，初生仔猪16头，分别于出生后定期日龄前腔静脉采血分离128头份血清样品，用单抗酶联免疫吸附试验检测血清猪瘟抗体滴度，结果表明，母猪猪瘟抗体效价持续较高，达100％保护率，哺乳前仔猪抗体效价为0，吃初乳后抗体水平不断提高，但抗体总体效价较低，仅有57．89％的保护率；仔猪20日龄前平源抗体水平差异较大，与母猪抗体水平不呈正相关。     

福州地区仔猪猪瘟调查及防制建议

近年来，福州地区一些猪场在初生至保育后的仔猪中陆续发生仔猪猪瘟，表现明显的窝发性，死亡率高，持续时间长，危害严重。１　仔猪猪瘟疫情调查　经调查，发病场母猪均经猪瘟疫苗免疫过，剂量为２～４头份，少数场还实施超免；仔猪免疫程序不规范。以ＤｏｔＥＬＩＳＡ检测发现，多数母猪抗猪瘟弱毒抗体水平偏低，仔猪抗体水平不足；母猪抗体水平偏低的猪场，主要见初生至２０日龄乳猪发生猪瘟；母猪抗体水平正常的猪场，也有６０～８０日龄的肥育猪发生猪瘟。通过检测猪群抗猪瘟强毒抗体，发现大部分疫情场母猪呈阳性，少数无病场也出现…     

应用FA及PPA-ELISA技术对猪瘟的检测

用免疫荧光抗体诊断技术及单克隆抗体纯化酶联免疫吸附试验诊断技术对疑为猪瘟病毒感染猪进行了检测 ,重点阐述了 2种方法的技术原理和操作过程。通过用免疫荧光抗体诊断技术检测了 5份病料 ,其中有 2份为阳性 ,阳性率为 40 % ;用单克隆抗体纯化酶联免疫吸附试验诊断技术检测了猪瘟血清抗体 ,在 40头母猪血清样品中 ,猪瘟弱毒抗体效价 OD值较高 ,有 1 0 0 %的保护率 ,但是发现母猪群中有 1 0 %隐性猪瘟感染 ,其强毒抗体效价 OD值大于 0 .5,体内带有猪瘟病毒。结果及过程表明此两种诊断方法检测快速、鉴别准确、分辨率高     

用单克隆抗体纯化酶联免疫吸附试验监测猪瘟抗体发现隐性猪瘟

用单克隆抗体纯化酶联免疫吸附试验监测瘟血清抗体。测得该场母猪４０份血清样品中，猪瘟弱毒抗体效价ＯＤ值较高，有１００％保护率，测得仔猛进４０份血清样品中，猪瘟弱毒抗体效价ＯＤ值适中，有８７．６％的保护率。     

猪瘟感染和免疫状况的血清学调查

从宁波市11个县（市）的17个集约化猪场随机采集猪血分离血清，共3437份．其中母猪878份，育肥猪1017份，生长猪778份，哺乳仔猪764份。受检猪均进行过猪瘟疫苗免疫。检验使用猪瘟弱毒或强毒单抗纯化的酶联抗原建立的间接ELISA诊断试剂盒，所用的纯化抗原，阴、阳性标准血清和相关试剂均购自中国兽药监察所。检测结果，猪瘟强毒（野毒）感染率平均14．1％，其中哺乳仔猪（45日龄内）为9．82％。     

猪瘟兔化弱毒犊牛睾丸细胞苗免疫程序研究

给空怀母猪免疫接种猪瘟兔化弱毒犊牛睾丸细胞苗１５００个兔感染量，以ＰＰＡ－ＥＬＩＳＡ监测其血清抗体。结果，ＥＬＩＳＡ效价ＯＤ值保护率６～７个月为１００％，８个月为７７．５％，表明１５００个兔感染量免疫母猪，一年应免疫接种２次，才能避免非免空隙，保持坚强免疫力。给怀孕母猪免疫，所产亲代仔猪的母源抗体消失很快，ＥＬＩＳＡ效价ＯＤ值保护率，１０日龄为９６．５％，２０日龄为７１．６％，３０日龄为４０％，４０日龄为１２．５％。给３０日龄仔猪免疫接种１５００个兔感染量，以ＰＰＡ－ＥＬＩＳＡ检测其免疫后６、７、８、９、１０个月的血清抗体，结果其ＥＬＩＳＡ效价ＯＤ值保护率６～９个月均为１００％，１０个月为９４％；攻ＨＣＶ强毒，６～１０个月均１００％保护。综上试验证明，仔猪３０日龄、母猪空怀免疫接种猪瘟兔化弱毒犊牛睾丸细胞苗１５００个兔感染量，是最佳的免疫程序。     

猪瘟免疫程序探讨

我们从1983年开始进行猪瘟疫苗的免疫程序接种试验、推广、研究。首先进行了不同日龄仔猪接种猪瘟兔化弱毒疫苗150个兔体感染量的试验。接种后分别在免疫后4、7、9、11、13月龄进行中和抗体效价监测。试验结果表明:母猪经过免疫所生仔猪在55日龄、60日龄注苗,免疫后8月龄监测体内中和抗体效价在16倍以上,经攻毒试验,能抵抗猪瘟强毒攻击和同居感染、然后剖检,酶标检验为阴性,无临床和剖检变化;母猪     

初生仔猪先天性震颤疑为注射猪瘟疫苗引起

初生仔猪先天性震颤疑为注射猪瘟疫苗引起仔猪先天性震颤的发生与母猪怀孕期间注射过猪瘟兔比弱毒疫苗是否有关，对此，将我场发生的病例介绍如下。－、发病情况１９９３年４～６月间，我场第１幢猪舍共４０头母猪，其中有２６头母猪在怀孕期间（怀孕３个月左右）注射过常...     

猪瘟病毒持续感染对母猪繁殖性能及仔猪猪瘟疫苗免疫效力的影响

利用来源于同一猪场的2头猪瘟病毒(HCV)持续感染的带毒母猪及所产35头仔猪(包括13头死胎)和6头阴性对照猪,观察母猪的胎儿发育成活状况、仔猪HCV带毒率及HCV垂直传播对仔猪猪瘟兔化弱毒疫苗(HCLV)免疫效力的干扰作用,同时进行水平传播试验和观察HCV持续感染对母猪繁殖功能的影响。结果表明：HCV持续感染对其中1头母猪的胎儿发育和成活有明显影响,而对另1头母猪的胎儿发育没有明显影响;HCV持续感染母猪可经过胎盘垂直传播病毒给仔猪,传播率达45％～86％;吃初乳和接种HCLV不能阻止带毒仔猪的死亡,9头带毒仔猪在45d内死亡4头;免疫HCLV不能使带毒仔猪产生免疫保护力。5头猪在强毒攻击后死亡4头;HCV垂直传播的带毒猪可发生水平传播,并引起3／4感染猪死亡;HCV持续感染可引起母猪生殖系统病理变化。导致繁殖障碍。     

猪圆环病毒2b亚型的分离鉴定及基因组序列分析

为分离鉴定流行于重庆某猪场的猪圆环病毒2型,本研究从断奶仔猪多系统衰竭综合征猪的淋巴结病料中进行病毒学检测,病毒利用PK-15细胞增殖,其基因组序列经克隆、测序、拼接获得,并完成对全序列的生物信息学分析鉴定。结果获得了1株猪圆环病毒2型(命名PCV-2CQ1),该毒株的全序列大小为1 767bp,同源性分析发现该病毒与国内公布的PCV-2毒株同源性超过了90%,尤其与广西分离株同源性达100%;系统进化分析本分离病毒与浙江株(EU257511)、黑龙江株(HM038032)聚类到一起,形成一个进化分支,同属于PCV-2b型;对编码的衣壳蛋白分析发现,PCV-2CQ1Cap氨基酸发生了较大变异,与强毒株同源性较高,考虑到本病毒源自PMWS病猪,推测该毒株属于强毒株。     

猪伪狂犬病灭活疫苗(HB-J株)对兔与猪免疫攻毒保护平行关系的研究试验

用研制的连续3批猪伪狂犬病灭活疫苗(HB-J株)分别以不同剂量免疫健康兔和断奶仔猪,检测其免疫28 d后的血清抗体,采用血清中和试验法测定血清中和指数,并对免疫28 d后的兔和断奶仔猪分别进行攻毒,统计各组兔和断奶仔猪免疫后攻毒保护率。结果表明,兔免疫28 d后的血清抗体中和指数为794～1258时保护率为60%～80%,血清抗体中和指数≥1479时可获得100%保护;仔猪免疫28 d后的血清抗体中和指数为229～269时保护率为60%～80%,血清抗体中和指数≥331时可获得100%保护。兔与仔猪对猪伪狂犬病灭活疫苗(HB-J株)均产生良好的免疫应答反应,抗体值较高者获得保护率相对较高,兔与猪免疫与攻毒保护呈现平行关系。     

非典型猪瘟和隐性猪瘟的诊断和防制

疑某猪场发生非典型猪瘟，采取病死猪的脾、淋巴结，用Ｄｏｔ－ＥＬＩＳＡ法检测猪瘟抗原，结果阳性，诊断为猪瘟。同时用ＳＰＡ－ＥＬＩＳＡ法对猪群开展猪瘟抗体的检测，先后采集７５头份仔猪血样（２０～２８日龄），８５０头份生产母猪血样。检测结果表明，猪瘟抗体水平低于保护值（ＯＤ＜０．３）的仔猪１１头，占抽检仔猪的１４．６％，母猪１０头，占生产母猪的１．１７％。为此对以上低抗体的猪用猪瘟兔化苗再次进行加强免疫接种，经１５天后检测其血清抗体的ＯＤ值，结果仍然没有升高。通过本试验证实，猪瘟低抗体的猪，对免疫的应答能力很差，低抗体的母猪还可能成为猪瘟的隐性感染者，并能垂直传播到下一代，是非典型猪瘟的传染源。淘汰低抗体的母猪，是控制和消灭非典型猪瘟的有效措施。     

Bovine Viral Diarrhea Virus in Swine: Characteristics of Virus Recovered from Naturally and Experimentally Infected Swine

A noncytopathogenic field strain of bovine viral diarrhea virus (BVDV) was isolated from an Iowa farm brood sow and from her hysterectomy-derived, colostrum-deprived (HDCD) piglets. This field isolant was fully virulent for a neonatal calf. The NADL strain of BVDV was passaged through a series of HDCD piglets with no resultant loss of virulence for neonatal calves. Most of the BVD viral isolants recovered from pigs had been changed from a cytopathogenic biotype to a noncytopathogenic biotype. Circumstantial evidence points to swine as “carrier” hosts of BVDV.     

应用灭光定量RT-PCR方法检测PRRSV变异株在仔猪体内动态分布

为进一步了解高致病性猪繁殖与呼吸综合征病毒(PRRSV)变异株(HuN4株)在体内的动态分布规律和特点,探讨病毒对组织器官的嗜性,本研究将HuN4株和细胞传代致弱毒株HuN4-F65人工感染40日龄健康仔猪,分别于感染后1 d、3 d、5 d、7 d、10 d、14 d、21 d和28 d各迫杀2头,并应用建立的荧光定量RT-PCR方法对脑、颌下淋巴结、扁桃体、肺脏、肝脏和十二指肠等组织及血清中的PRRSV进行定量检测.结果显示:感染后HuN4组各器官病毒载量比HuN4-F65组高100倍,病毒栽量峰值期出现在感染后7 d,随后呈下降趋势.HuN4株在仔猪体内分布广泛,在21 d的试验期内持续存在,并且各器官的病毒载量呈正态分布规律;而HuN4-F65株血清病毒载量较低,并且集中在单核巨噬细胞相对密集的扁桃体和颌下淋巴结,与HuN4株主要嗜性器官肺脏相比发生了改变.     

猪瘟不同顺序零天免疫的免疫效果比较

以猪瘟兔化弱毒细胞苗分别免疫3组初生仔猪，每头1．5头剂。第1组20头先免疫，1小时后吸初乳。第2组15头，吸初乳后1小时免疫。每3组13头，吸初乳后半小时免疫。75日龄，以猪瘟弱毒单抗酶联方法测定3组动物的平均抗体（OD值）分别为0．25、0．23及0．21。80日龄，每组各随机抽出4头猪，连同非免疫对照猪6头以猪瘟石门系强毒攻击后，对照猪全死，第1组100％保护，第2组75％保护，第3组50％保护。第1组的免疫效果明显优于其他两组。     

Comparative immunohistopathology in pigs infected with highly virulent or less virulent strains of hog cholera virus

Eight pigs were inoculated subcutaneously with a highly virulent hog cholera virus (HCV) strain ALD. The infected pigs developed severe illness and became moribund on postinoculation day (PID) 7 or PID 10. Histologic lesions were characterized by severe generalized vasculitis, necrosis of lymphocytes, and encephalitis. HCV antigen was detected in crypt tonsilar epithelial cells, macrophages, and reticular endothelial cells of lymphoid tissues. Antigen localization corresponded well with histologic lesions. Five pigs were inoculated with less virulent HCV Kanagawa/74 strain and were euthanatized on PID 30. All five infected pigs recovered from the illness but became stunted. They also had a slight follicular depletion of lymphocytes, histiocytic hyperplasia, and hematopoiesis in the spleen. Less virulent HCV antigen was observed in the tonsils, kidneys, pancreas, adrenal glands, and lungs. Although antigen localization was less associated with histologic lesions, immunoreactivity was stronger than that in the pigs infected with the ALD strain of HCV. An almost complete loss of B lymphocytes was recognized in pigs infected with the ALD strain and was correlated with follicular necrosis in lymphoid tissues. Loss of B lymphocytes was not prominent in the pigs infected with Kanagawa/74 strain. The number of CD4+ and CD8+ T lymphocytes was significantly higher than that in the noninfected control pigs.     

鸡传染性法氏囊病毒超强毒株的分离及生物学特性鉴定

用SPF鸡及鸡胚，从吉林某鸡场病死鸡的法氏囊组织到一株超强毒株（J20株）。此病毒不能凝集鸡的红细胞，可以被IBDV标准阳性血清检出IBDV抗原。通过对J2001分离毒株进行回归实验，测定病毒效价EID50达10^6/0.2ml，发病率为100％，死亡达70％；病毒理化特性试验，电镜观察等证实J20株为鸡传染性法氏囊病超强毒株。     

Colonization of suckling pigs by Streptococcus suis with particular reference to pathogenic serotype 2 strains.

Three swine commercial farms with high mortality rates in nursery pigs due to Streptococcus suis serotype 2 were studied. Brain samples from diseased animals were collected for a period of 6 to 10 mo and used to isolate the strain that was responsible for the mortality (virulent strain) in each farm. Tonsil swabs from piglets at 5, 10 and 15 d were taken to assess both total colonization and colonization by the virulent strain. The effect of sow vaccination against S. suis on colonization was evaluated in 1 of the farms. All suspect tonsil isolates were identified biochemically and then tested against serotype 2. The genomic patterns of serotype 2 isolates were compared to that of the virulent strain using Rep-PCR. Results showed that total colonization by S. suis occurred very early in the pigs' life, with most animals being colonized by weaning age. Prevalence of colonization by serotype 2 strains was much lower than total colonization. After comparing serotype 2 isolates with the virulent strains, only 1 tonsillar isolate had the same genomic pattern as the virulent strain and it belonged to a 4-week-old weaned pig. The genomic pattern of the virulent strain was not found in any tonsillar isolate from 15-day-old or younger pigs. Although limited by sample size, sow vaccination against S. suis increased total colonization at the same time significantly decreasing colonization by serotype 2 strains. Even though most pigs are colonized early in age by S. suis, colonization by the virulent strain is of low prevalence and delayed in time. This could constitute a risk factor for developing the disease later in time, because animals would be colonized when maternal immunity is no longer present, allowing the organism to become systemic.