金华猪仔猪猪瘟母源抗体衰减规律初探

仔猪吸吮经猪瘟疫苗免疫的母猪的初乳后,对10头母猪和各所产仔猪中的任意2头在14、21、28、35日龄分别采血,采用正向间接血凝试验检测猪瘟抗体水平,监测母源抗体在仔猪体内的消长规律,以探索金华猪仔猪猪瘟疫苗最佳首免时间;检测母猪抗体水平以探索对仔猪母源抗体的影响。结果发现,仔猪母源抗体水平随着日龄增大而逐级降低,半衰期为17d左右;仔猪母源抗体水平与母猪抗体水平成正比,随着日龄的增加母猪对仔猪母源抗体影响越来越低。     

猪口蹄疫和猪瘟疫苗同时注射免疫试验技术报告

本文在研究仔猪口蹄疫母源抗体消长规律和仔猪口蹄疫免疫效果的基础上,探讨了口蹄疫疫苗和猪瘟疫苗不同组合免疫的相互影响。结果表明:未吃初乳前的新生仔猪体内口蹄疫母源抗体效价<5log2,仔猪吃初乳后,其抗体水平与母猪相当(100%),此后从第7天开始下降,到35日龄时,其O型抗体效价下降到80%。仔猪断奶后阉割时免疫注射口蹄疫二价苗,到注射后28天,O型抗体的效价才达到(≥5log2)27.78%,亚I型抗体效价(≥1:22-90)29.73%。在60日龄加强免疫口蹄疫苗后才能使抗体效价达到70%以上。在仔猪阉割时,同时分点注射口蹄疫二价苗和猪瘟苗,或者口蹄疫O型灭活苗和猪瘟苗,此二种组合与单独注射口蹄疫疫苗相比所产生的口蹄疫抗体效价在生物统计分析上没有差异。在仔猪阉割时注射口蹄疫O型合成肽苗和猪瘟疫苗,21天后口蹄疫O型抗体效价可达70%以上。     

仔猪口蹄疫母源抗体衰减规律研究

为了明确仔猪体内A型口蹄疫母源抗体衰减规律,为仔猪口蹄疫疫苗首免时间的确定提供理论依据,选取预产期相同、口蹄疫抗体水平(A型)有差异的5头母猪,每头母猪随机选取5头仔猪并分16个时间点采集外周血,利用液相阻断ELISA对仔猪体内A型口蹄疫抗体进行检测,评估其消减规律。结果显示:脐带血不传播母源抗体,仔猪获得母源抗体保护的唯一途径是吃母乳;仔猪采食初乳后体内A型口蹄疫母源抗体可在吃初乳后当天达到峰值,而后随时间增加而降低;当母猪分娩时抗体水平为1∶1024时,仔猪63日龄左右体内抗体水平降低至1∶45;当母猪分娩时抗体水平为1∶720时,仔猪56日龄左右体内抗体水平降低至1∶45;当母猪分娩时抗体水平为1∶360时,仔猪28日龄左右体内抗体水平降低至1∶45。仔猪体内A型口蹄疫抗体衰减时间和分娩时母猪抗体水平呈正相关性。本文研究结果为制定科学合理的仔猪口蹄疫疫苗免疫程序提供数据支撑。     

不同来源的仔猪猪瘟母源抗体检测结果比较

<正>仔猪可通过吮吸免疫母猪的初乳获得猪瘟母源抗体使仔猪获得对猪瘟病毒(HCV)的被动免疫保护,这种获得性免疫可以使仔猪在疫苗免疫之前免受HCV的感染,但这种保护会随着仔猪日龄的增长和母源抗体滴度的衰减而降低。根据仔猪母源抗体水平及母源抗体消长规律选择最佳的首免时间对预防猪瘟的发生相当关键,为此我们选择了3个饲养条件不同、仔猪来源不同的猪场的仔猪进行猪瘟母源抗体情况调查,以了解仔猪的母源抗体水平,探讨首免日龄     

仔猪O型口蹄疫疫苗首免时间的确定

为摸索猪O型口蹄疫灭活疫苗对猪的免疫效果,我们对初生仔猪口蹄疫母源抗体自然消长规律进行了跟踪监测,来筛选出较佳的口蹄疫首免时间,切实做好猪场口蹄疫的防控工作。采用固相竞争ELISA诊断试剂盒检测母源抗体和免疫抗体,根据仔猪各阶段免疫抗体的消长规律初步确定母源抗体的保护期,制订合理的首免时间。通过试验证明猪场仔猪口蹄疫母源抗体在35~40日龄之间维持在较高水平,随着日龄的增长平缓下降,40日龄后抗体水平急剧下降。依据口蹄疫疫苗注射后抗体产生所需时间推断,在仔猪35~40日龄左右进行口蹄疫首免,最为合理。     

口蹄疫母源抗体对仔猪疫苗免疫的影响

<正>为了探讨母源抗体对猪口蹄疫疫苗免疫效果的影响,以便指导生产中仔猪口蹄疫的免疫工作,从而更有效地预防口蹄疫,本试验通过在相同日龄选用相同的疫苗组合,分别对有猪口蹄疫母源抗体的仔猪和没有猪口蹄疫母源抗体的仔     

母源抗体对仔猪猪瘟疫苗免疫效果的影响

针对猪瘟疫苗在仔猪免疫日龄界定问题上的模糊认识,我们对新生仔猪猪瘟母源抗体持续时间和对免疫效果的影响进行了实验检测。通过对20日龄、30日龄、40日龄的仔猪母源抗体检测,掌握其消退规律,并对相应日龄不同母源抗体水平的仔猪进行猪瘟疫苗免疫接种（正常剂量）,接种后在14d和28d分别检测抗体效价,从而分析出仔猪初免日龄的最佳时间和免疫方法。     

仔猪超前免疫的实施及其实施中应注意的问题

<正>刚出生的仔猪可以从吸吮母猪的初乳中获得母源抗体,并能有效地抵抗病原菌的侵袭,因此,一般养猪场户不提倡过早地给初生仔猪接种免疫疫苗,如果养猪场户过早地给初生仔猪接种免疫疫苗,不仅会干扰和破坏母源抗体,而且对仔猪的免疫效果也不会那么理想,所以,一般养猪场户对仔猪接种免疫猪瘟疫苗均提倡在仔猪20~25日龄进行首免,待仔猪生长到60日     

猪瘟高致病性猪蓝耳病和口蹄疫母源抗体的测定及3种疫苗首免日龄的确定

为了确定仔猪免疫猪瘟、高致病性猪蓝耳病和猪口蹄疫3种疫苗的最佳首免日龄,课题组通过酶联免疫吸附试验对米东区一养猪场刚刚生产的30头仔猪开展了3种猪病母源抗体持续期测定,结果表明:母猪的抗体水平和仔猪是否吃到初乳决定着仔猪的母源抗体持续的时间;在1~7日龄仔猪的母源抗体水平达到最高峰,7日龄后,母源抗体水平逐渐衰减,并与日龄呈负相关;猪瘟、高致病性猪蓝耳病和O型口蹄疫的母源抗体持续期分别为28~32 d、30~35 d和29~34 d,根据这3种猪病的母源抗体持续期,确定了这3种疫苗联合免疫的最佳首免日龄为28~35日龄。     

规模化猪场仔猪口蹄疫免疫程序的制定

本试验通过研究免疫状况良好的母猪群所产仔猪母源抗体的获得方式,仔猪体内母源抗体的持续时间,仔猪不同免疫程序的免疫效果,发现初生仔猪遵守被动免疫传递规律,仔猪体内的口蹄疫抗体水平也有自己的消长规律:哺乳后3～7d抗体水平达到最高,35日龄后开始下降,63日龄左右抗体保护率已经低于60%。所以,仔猪口蹄疫疫苗首次免疫的时间应定在35日龄,49日龄还需加强一次;疫苗的剂量:首免为1头份(2mL),加强时为2头份(3mL)。     

牛用口蹄疫AsiaI—O型双价灭活苗与猪用口蹄疫O型灭活苗对猪的免疫效果比较试验

使用牛用口蹄疫AsiaI-O型双价灭活苗与猪用口蹄疫O型灭活苗分别接种50d商品猪和怀孕90d种猪,免疫前和免疫后的3w及7w进行抗体水平检测。O型口蹄疫采用正向间接血凝试验、AsiaI型口蹄疫采用液相阻断ELISA检测。同时对接种猪进行免疫应激观察。结果显示：猪使用牛用口蹄疫AsiaI—O型双价灭活苗3w后口蹄疫AsiaI的抗体水平十分低,最高只有5％,口蹄疫O型抗体合格率在35％以上;而注射猪用口蹄疫O型灭活苗的O型抗体水平合格率只有35％。而牛用口蹄疫AsiaI-O型双价灭活苗两次接种后,AsiaI和O型抗体水平均达到大于70％的要求。     

The Recombinant Nonstructural Polyprotein NS1 of Porcine Parvovirus (PPV) as Diagnostic Antigen in ELISA to Differentiate Infected from Vaccinated Pigs

To differentiate pigs infected with porcine parvovirus (PPV) from those vaccinated with inactivated whole-virus vaccine, an enzyme-linked immunosorbent assay (ELISA) based on detection of a nonstructural polyprotein 1 (NS1) was developed. A threshold of 0.23 optical density units was established and the assayhad high specificity (100), sensitivity (88), accuracy (90) and positive predictive value (100) using haemagglutination inhibition as the standard method. A reproducibility test revealed that the coefficients of variation of sera within-plates and between-run were less than 10%. The assayshowed no cross-reactivitywith antibodies to porcine reproductive respiratorysyndrome virus, pseudorabies virus, foot and mouth disease virus, Actinobacillus pleuropneumoniae, Toxoplasma or Chlamydia. Sera obtained from pigs infected with PPV reacted with recombinant NS1 protein in the ELISA. Sera from pigs vaccinated with inactivated whole virus did not recognize this protein in the ELISA. In contrast, antibodies against PPV whole virus were present in both PPV-infected and vaccinated animals. Serum conversion against NS1 was first detected 10 days after infection and NS1-specific antibodies were detectable up to half a year post infection. In conclusion, the PPV-NS1 ELISA can differentiate PPV-infected versus inactivated PPV-vaccinated pigs and could be applied in disease diagnosis and surveillance.     

Comparison between Haemophilus parasuis infection in colostrums-deprived and sow-reared piglets

The aim of this study was to compare the development of Glasser's disease in sow-reared and colostrum-deprived piglets. Ninety piglets from a commercial pig farm in Spain were used. The farm was positive for Haemophilus parasuis. Fifty-two pigs were sow-reared (SR) and 38 were colostrum-deprived (CD) piglets. The animals were intratracheally inoculated with H. parasuis serovar 5 and sacrificed at 1, 2 and 3 days post-infection. To assess the development of disease, antibody titers, clinical signs, pathological lesions, microbiological isolation and PCR amplification were compared between the groups. Inoculation of SR pigs did not cause clinical signs or lesions of Glasser's disease. In SR pigs, H. parasuis isolation and specific PCR amplification from tissues showed a very low number of positive samples. In contrast, in CD pigs, inoculation resulted in the typical signs and lesions of Glasser's disease. Positive microbiological isolation and specific PCR products were obtained from the majority of the tissues tested, and no antibodies against H. parasuis were detected. The experimental infection using CD pigs describes a successful method to study this microorganism and confirms the important role that maternal antibodies play in protection against clinical signs and disease.     

口蹄疫疫苗效检模型动物测毒及口蹄疫种毒冻干试验

应用豚鼠作为口蹄疫疫苗效检模型动物检测口蹄疫病毒对模型动物的病原性.用体重400 g左右的豚鼠,将猪O型口蹄疫灭活疫苗效检攻毒毒株ORMF8经后肢蹠部皮内注射途径进行测毒.测毒结果表明,口蹄疫病毒可引起豚鼠出现典型发病,并产生明显病变,ORMF8种毒对豚鼠的毒价可达105.5ID50/0.2 mL.将乳鼠中和试验用种毒OMⅡ按一定比例加入5%蔗糖脱脂牛奶稳定剂进行冷冻真空干燥试验,3次冻干试验结果表明,种毒冻干后病毒含量有一定程度的下降,但下降程度不显著.     

Skin test as herd diagnosis for Aujeszky's disease (Pseudorabies) in swine

Summary The value of a skin test for the diagnosis of Aujeszky's disease (pseudorabies) in swine was examined. Semipurified and concentrated antigens, obtained by ether/tween 80 inactivation of Aujeszky's disease virus, were inoculated intradermally into seronegative, experimentally infected and vaccinated swine and into pigs with maternal antibodies. A specific skin reaction, characterized by a visible indurated swelling, was observed within 24 hours in animals with active immunity, No reaction was seen in pigs with maternal immunity or in seronegative uninfected and unvaccinated animals. In the infected and vaccinated groups, 89% and 58% respectively of the animals with seroneutralizing antibodies were positive by the skin test response. Positive reactions were observed as early as 8 days after the infection. All but one seronegative animals remained free of antibodies after 2 consecutive skin tests and the course of decline of maternal antibodies was not changed. An earlier skin test did not lead to sensitization for a later application. The present results, together with field experience on 8 farms, revealed that the skin test could be considered a reliable method for diagnosis of Aujeszky's disease in swine on a herd basis.     

Recent outbreak of foot and mouth disease in Ivory Coast]

An outbreak of foot and mouth disease (FMD) due to SAT2 occurred among cattle, sheep and pigs in C?te-d'Ivoire. The morbidity and mortality were low so vaccination of only high value livestock in intensive production systems was suggested.     

内蒙古地区牛羊口蹄疫灭活疫苗的免疫效果比较研究

为准确掌握牛羊口蹄疫疫苗免疫效果,2012年对内蒙古自治区的牛羊口蹄疫O—AsiaI型双价灭活疫苗和牛羊口蹄疫A型灭活疫苗免疫效果进行了监测。采用液相阻断ELISA方法。共检测了8个旗县23018份免疫牛羊口蹄疫O—AsiaI型双价灭活疫苗和牛羊口蹄疫A型灭活疫苗15日、30日、60日的血清中口蹄疫免疫抗体水平。结果显示,牛羊口蹄疫疫苗免疫效果总体良好,免疫抗体合格率超过了70％。规模化奶牛养殖场免疫效果稳定,散养地区免疫效果稳定性差,且不同厂家的疫苗免疫效果不同,加强免疫后A、B、D三个厂家抗体合格率能达到100％,C厂家的免疫效果较差,抗体合格率为93-3％。采用3ABC—ELISA检测试剂盒对部分地区牛羊进行感染抗体检测,结果为阴性。     

抗猪口蹄疫病毒单克隆抗体的抗原识别位点分析

用ELISA叠加试验，对5株具有ELISA反应特性的抗猪口蹄疫病毒(FMDV)单克隆抗体(McAb—A6、F9、G17、G52、S25)的抗原识别位点进行检测。抗体反应增值结果表明，5株单抗分别针对4个不同抗原住点，McAb—G17、G52、S25识剐的住点各不相同，其中McAb—G7、G52识别的位点有部分重叠，McAb—A6、F9识别同一位点，位于G17、G52位点的重叠区内。     

Development and Application of Two-temperature RT-PCR for Detectionof Type O Foot and Mouth Disease Virus

According to the gene sequences analysis of foot and mouth disease virus (FMDV) in GenBank,a pair of specific primers was designed in the conserved sequence of type O FMDV P1 gene. The reaction parameters were optimized using the uniform design method to develop a two-temperature RT-PCR method for detection of type O FMDV.The results of sensitivity and specificity showed that the two-temperature RT-PCR method was only specific for type O FMDV without amplification of the other viruses. The amplified fragment was same with the expected length.The cloning and sequencing results revealed that the sequence of amplified fragment had 100% simililarity to the target sequence,and the minimum detection quantity was 1.665 pg/μL,the effective detection rate was consistent with the three step RT-PCR sensitivity test results. 54 taper toxicity test pigs were detected,and positive identification results and three-step PCR results was consistent.Compared with the three-step PCR,it could save 20 min.These results indicated that the developed two-temperature RT-PCR for detection of type O FMDV was a kind of accurate,rapid,specific and sensitive detection method.     

Evaluation of transmission of swine influenza type A subtype H1N2 virus in seropositive pigs

OBJECTIVE: To examine clinical signs, virus infection and shedding, and transmission of swine influenza virus (SIV) subtype H1N2 among seropositive pigs. ANIMALS: Eighteen 3-week-old pigs with maternal antibodies against SIV subtypes H1N1, H3N2, and H1N2. PROCEDURE: Ten pigs (principal) were inoculated intranasally with subtype H1N2 and 2 groups of contact pigs (n = 4) each were mixed with principal pigs on day 7 (group 1) or 28 (group 2). Two principal pigs each were necropsied on days 4, 14, 21, 28, and 42 days after inoculation. Four pigs in each contact group were necropsied 35 and 14 days after contact. Virus excretion was evaluated after inoculation or contact. Lung lesions and the presence of SIV in various tissues were examined. RESULTS: Mild coughing and increased rectal temperature were observed in principal pigs but not in contact pigs. Nasal virus shedding was detected in all principal pigs from day 2 for 3 to 5 days, in group 1 pigs from day 2 for 4 to 9 days after contact, and in group 2 pigs from day 4 for 2 to 6 days after contact. Trachea, lung, and lymph node specimens from infected pigs contained virus. Antibody titers against all 3 subtypes in all pigs gradually decreased. CONCLUSIONS AND CLINICAL RELEVANCE: Protection from viral infection and shedding was not observed in pigs with maternal antibodies, but clinical disease did not develop. Vaccination programs and good management practices should be considered for control of SIV subtype H1N2 infection on swine farms.