传染性支气管炎病毒(M41株)HI试验抗原的特异性和敏感性试验

采用本研究室制备的3批传染性支气管炎病毒(IBV,M41株)HI试验抗原,分别对100份和80份不同鸡血清进行IBV HI抗体检测,同时用IBV ELISA抗体检测试剂盒进行检测,比较两种不同方法检测的特异性和敏感性。结果显示,特异性试验中80份SPF鸡血清,自制抗原检测均为阴性,IBV ELISA检测79份为阴性,10份其他鸡病血清,两种方法检测9份均为阴性,10份IBV阳性血清两种方法检测均为阳性;敏感性试验中,74份已知IB疫苗免疫或IBV M41株感染鸡血清IBV HI检测72份为阳性,阳性检出率为97.3%(72/74),IBV ELISA检测74份均为阳性,阳性检出率为100%(74/74),SPF鸡血清及其他鸡病血清,两种方法检测均为阴性,两种检测方法总符合率为97.5%,差异不显著(P0.05)。试验结果证明,本研究室自制抗原具有良好的特异性,特异性为100%,抗原同时具有良好的敏感性,但IBV ELISA方法的敏感性要高于IBV HI方法。     

筛选猪瘟抗体阴性猪检测方法的比较

评价ELISA法用于筛选猪瘟抗体阴性猪的可行性,分别采用两种商品化猪瘟抗体ELISA检测试剂盒检测了61份猪血清样品,并与兔体中和试验方法进行了比较。兔体中和试验法检测出4份阳性、2份可疑、55份阴性,而两种ELISA试剂盒均检测出6份阳性、55份阴性;两种ELISA方法与兔体中和试验检测结果阴性符合率均为100%（55/55）。结果表明,ELISA法更加敏感,可以替代兔体中和试验方法用于筛选猪瘟抗体阴性猪。     

猪乙型脑炎间接ELISA与血凝抑制试验方法的比较

用血凝抑制试验和间接ELISA两种方法检测乙脑阳性血清均呈阳性反应,检测乙脑阴性血清均呈阴性反应。用间接ELISA对来自9个猪场74份送检血清进行了猪乙脑病毒（Japanese encephalitis virus,JEV）抗体检测,并与血凝抑制试验（HI）进行对比,两种方法检测总符合率为85.1%(63/74),经统计分析,检测结果差异不显著(P＞0.05)。对来自无猪乙脑病猪场24头健康猪的血清进行检测,两种方法结果均为阴性,符合率为100%。对10份阳性血清进行检测,ELISA检测效价较HI效价高,表明ELISA比HI敏感。结果表明,ELISA与HI检测结果相符,前者更适用于猪血清中乙脑IgG抗体的大规模检测。     

马动脉炎病毒血凝抑制试验研究及其应用

用马动脉炎病毒（EAV）免疫SPF豚鼠，4周后采血做血凝抑制试验（HI），其抗血清可以抑制血凝抗原对小鼠红细胞的凝集反应，抗原和抗血清在4℃感作24h后可以检测到最高的HI抗体效价，同时结果显示HI抗体与中和抗体产物呈正相关。对561份来自新西兰、吉尔吉斯、沙特阿拉伯及内蒙古、新疆的马血清用HI试验和微量血清中和试验（NT）进行EAV抗体检测，HI和NT阳性符合率为94．7％，血凝抑制抗体与中和抗体效价呈显著的正相关。     

鸡新城疫、禽流感二联灭活疫苗与同类产品的免疫效力比较

将鸡新城疫、禽流感（H9亚型,SY株）二联灭活疫苗与市售同类对照苗分不同剂量皮下注射接种30日龄SPF鸡,免疫后定期采血,分离血清,通过检测血清中ND和AI的HI抗体水平比较各组鸡抗体产生期、抗体高峰及免疫持续期,并进行不同血凝抗原检测HI抗体结果的对比。试验鸡血清样品检测结果显示,免疫鸡抗体产生期为免后2周内,免后8周和5周ND和AI的HI抗体滴度分别达到峰值,抗体至少可持续28周以上,两种灭活苗之间免疫效果基本相当。     

核酸斑点杂交法与ELISA在SPF鸡检测弱毒疫苗中ALV污染的应用与比较

本研究对SPF鸡检查法在检测弱毒疫苗中低剂量禽白血病病毒(ALV)污染时的核酸斑点杂交法和ELISA进行了比较。分别以10 TCID_(50)/羽份和5 TCID50/羽份ALV-A人为污染一批商品化新城疫(ND)活疫苗,将污染ND疫苗各接种10只SPF鸡,以ELISA定期检测ALV抗体并利用PCR结合核酸斑点杂交法检测血液中ALV核酸。结果显示,在免疫污染疫苗后连续3周内ALV抗体全部为阴性,而核酸斑点杂交法检测表明自免疫后两周开始就出现ALV阳性。结果提示在利用经典的SPF鸡检查法检测弱毒疫苗中ALV污染时,结合对病原核酸的检测有助于节省检测时间和降低漏检率。     

鸡新城疫－传染性支气管炎－传染性法氏囊病三联灭活疫苗对不同日龄雏鸡的免疫效力研究

为评估鸡新城疫（ND）-传染性支气管炎（IB）-传染性法氏囊病（IBD）三联灭活疫苗对不同日龄和不同水平母源抗体雏鸡的免疫效力和持续期,本试验用该疫苗免疫7、14、21日龄SPF雏鸡和有母源抗体的普通雏鸡,免疫后采血测定ND血凝抑制抗体（HI Ab）、IB血凝抑制抗体（HI Ab）及IBD中和抗体（NA）,并用传染性法氏囊病病毒（IBDV）强毒攻击。结果显示,7日龄SPF雏鸡免疫后21 d ND HI抗体、IB HI抗体及IBD中和抗体效价分别为7.9log2、6.9log2和14.1log2,SPF鸡日龄越大,抗体水平越高;28日龄SPF鸡免疫后3个月,0.3 mL免疫剂量组试验鸡ND HI、IB HI及IBD中和抗体效价分别达6.5log2、6.1log2和13.6log2,IBDV攻毒保护率均为100%（10/10）;不同日龄普通雏鸡免疫效果与SPF鸡试验一致,抗体水平随鸡日龄增大而升高,IBD攻毒保护率也都达到100%（10/10）。试验结果证实,鸡新城疫-传染性支气管炎-传染性法氏囊病三联灭活疫苗可使7、14及21日龄SPF雏鸡和普通雏鸡产生良好的免疫力,对雏鸡的免疫期至少为3个月。     

猪瘟抗体阴性猪筛选方法的比较

评价ELISA法用于筛选猪瘟抗体阴性猪的可行性,分别采用两种商品化猪瘟抗体ELISA检测试剂盒检测了61份猪血清样品,并与兔体中和试验方法进行了比较.兔体中和试验法检测出4份阳性、2份可疑、55份阴性,而两种ELISA试剂盒均检测出6份阳性、55份阴性;两种ELISA方法与兔体中和试验检测结果阴性符合率均为100%(55/55).结果表明,ELISA法更加敏感,可以替代兔体中和试验方法用于筛选猪瘟抗体阴性猪.     

间接ELISA和HI方法检测鸡新城疫病毒抗体的相关性分析

分别采用商品化的酶联免疫吸附试验（ELISA）抗体检测试剂盒和血凝抑制（HI）试验方法对152份临床血清样本和标准阴阳性血清进行新城疫病毒（NDV）抗体检测。比较间接ELISA和HI两种方法的相关性。研究结果表明，间接ELISA和HI两种方法呈显著相关，二者间的相关系数为0．9261：间接ELISA和HI两种方法检测NDV抗体的阳性符合率为96．8％，阴性符合率为92．9％，间接ELISA方法是一种敏感、特异、快速的血清学诊断方法，可以用于临床样本的大规模检测．     

猪脾转移因子增强禽白血病病毒A/B亚群抗体阳性鸡群免疫水平的研究

为了解猪脾转移因子(TF)对禽白血病病毒A/B亚群(ALV—A/B)抗体阳性鸡群免疫水平的影响,本研究以新城疫(ND)HI试验和淋巴细胞增殖试验分别检测ND HI抗体效价(log2x)和刺激指数(SI)作为指示参数,采集特佳、罗曼、海兰和伊莎共4个品种蛋鸡血样,并从中选出各60羽份(ALV-A/B抗体阳性、阴性鸡各半,ALV p27抗原均为阴性),将4个品种的ALV-A/B抗体阳性蛋鸡均分为实验组(联合接种TF 0.02 mL+NDV La Sota疫苗1羽份/羽,TF多肽含量为3.5 mg/mL,核糖含量为72.0μg/mL,脱E受体法效力检验活力为15%)和对照组(单独接种NDV La Sota疫苗1羽份/羽),于接种后21 d采血检测。结果显示,ALV-A/B抗体阳性鸡群(120羽份)的ND HI抗体效价均值(6.1±1.3)与阴性鸡群(120羽份)均值(6.2±1.3)差异不显著,但其SI均值(1.20±0.10)显著低于阴性鸡群(1.35±0.10)(p0.05);实验组(60羽份)的ND HI抗体效价和SI均值(9.0±1.3,1.73±0.15)显著高于对照组(60羽份)均值(7.8±1.2,1.39±0.16)(p0.05)。研究结果表明,ALV-A/B抗体阳性与鸡ND HI抗体效价相关性不大,而对SI具有抑制作用;TF具有增强ALV-A/B抗体阳性鸡群免疫水平的作用。     

黄芪多糖、当归多糖对鸡新城疫弱毒苗免疫增强作用

研究黄芪多糖、当归多糖对鸡新城疫疫苗的免疫促进作用,选择90只20日龄海兰鸡随机分成三组,每组30羽,每只鸡注射ND-Lasota弱毒冻干苗0．5mL,试验组Ⅰ、Ⅱ、Ⅲ分别注射黄芪多糖、当归多糖、复合多糖（0．5mL／羽）,在免疫后第10d、20d、30d、40d采血测定ND血凝抑制（HI）抗体。结果表明,黄芪多糖、复合多糖对NDHI抗体有明显的促进作用,与对照组差异极显著（P〈0．01）。结论：黄芪多糖、复合多糖可以明显提高鸡新城疫抗体水平。     

Comparison of Newcastle disease vaccines by serology using serum,tears and feather pulp samples

Seroconversion of 3 lentogenic commercial Newcastle disease (ND) vaccines and experimental V₄ vaccines was compared based on the haemagglutination inhibition (HI) test against ND. It was found that for primary vaccination all the vaccines produced similar response but for secondary vaccinations V₄ and LaSota were better than RDVF. Eighty-five samples each of serum, tears and feather pulp were collected from respective birds and antibody assessment was done against ND by HI test. The geometric mean HI titres (GMT) of serum samples were highest followed by tears and feather pulp samples before vaccination and 3 weeks after vaccination by oculonasal route and the difference was statistically significant (p<0.01). Three weeks after booster vaccination by oculonasal route, however, the GMT of serum samples were highest followed by feather pulp and tears samples. The ease of collection of feather pulp samples and their role in ND serology is discussed.     

Comparison of egg yolk and serum for the detection of Mycoplasma gallisepticum and M. synoviae antibodies by enzyme-linked immunosorbent assay

Egg yolk was evaluated in the enzyme-linked immunosorbent assay (ELISA) as an alternative source of antibodies for detection of Mycoplasma gallisepticum (MG) and M. synoviae (MS) infections in chickens. There was no statistically significant difference (P greater than 0.05) between the ELISA geometric mean titers (GMTs) of saline-diluted egg yolk and chloroform-extracted egg yolk, and both preparations had a high correlation coefficient (0.87 for MG; 0.97 for MS). The saline-diluted and chloroform-extracted yolk had a relative sensitivity of 90% and specificity of 98% in the MG ELISA; in MS ELISA they were 100% and 96%, respectively. Hemagglutination-inhibition (HI) results with chloroform-extracted samples were satisfactory, but those with saline-diluted samples were not. Neither preparation was satisfactory for use in the rapid plate agglutination (RPA) test. A 1-ml sample of yolk was compared with the whole-yolk method. The chloroform-extracted whole yolk yielded a significantly higher (P less than 0.05) GMT in the MG ELISA; however, there was no statistically significant difference (P greater than 0.05) between GMTs yielded by the two procedures in the MS ELISA. The correlation coefficients for the two sampling methods were 0.73 for MG ELISA and 0.63 for MS ELISA. ELISA detected no statistically significant difference (P greater than 0.05) between GMTs of serum and chloroform-extracted yolk from individual birds. Results with the HI test were comparable to those with ELISA on the same samples. The RPA test yielded comparable results on the serum samples. No statistically significant differences (P greater than 0.05) were observed in HI or ELISA antibody levels between egg-yolk samples and sera on random samples collected from nine flocks that were MG- and MS-free or were infected with MG, MS, or both; however, egg-yolk samples tended to have slightly higher titers than sera in both tests. The optimum screening dilution of chloroform-extracted yolk for detecting MG and MS antibodies by ELISA was 1:800.     

Comparison of a commercial H1N1 enzyme-linked immunosorbent assay and hemagglutination inhibition test in detecting serum antibody against swine influenza viruses.

Recently a commercial enzyme-linked immunosorbent assay (ELISA) kit for detecting antibody against H1N1 swine influenza virus (SIV) has been made available to diagnosticians and veterinary practitioners. Because the hemagglutination inhibition (HI) test has been considered the standard test for SIV serology, diagnostic performance of the new ELISA was evaluated using positive (n = 60) and negative (n = 188) serum samples from young pigs with known status of SIV infection and compared with that of the HI test. Both ELISA and HI test identified all negative animals correctly. None of the serum samples (n = 64) from pigs inoculated with H3N2 SIV was positive by ELISA for SIV antibody. The H1N1 SIV antibody detectable by ELISA appears to develop more slowly in comparison with antibody detectable by HI test. Although antibody was detected by HI test in all inoculated animals (n = 20) by day 7 postinoculation (PI), antibody was detected by ELISA in 0%, 75%, and 100% of the inoculated animals on days 7, 14, and 28 PI, respectively. Discrepancy in test results between the 2 serologic tests appeared to be because of differences in antibody isotypes detected by each test. Enzyme-linked immunosorbent assay mainly detected IgG antibody, whereas the HI test detects IgM antibody very efficiently as well as IgG antibody. Collectively, the commercial ELISA is highly specific for antibody to H1N1 SIV but may not identify positive animals at the early stage of infection as effectively as the HI test, particularly when SIV is introduced to a na?ve swine population.     

Use of egg yolk to determine antibody levels in chickens inoculated with a hemagglutinating duck adenovirus (adenovirus 127-like)

Chickens were experimentally infected with a duck adenovirus that has been shown to be serologically indistinguishable from Adenovirus 127. Sera and eggs were collected at intervals after exposure for antibody determination by the hemagglutination-inhibition (HI) test, the enzyme-linked immunosorbent assay (ELISA), and the immunodiffusion (ID) test. Egg yolks were processed for use in the serological tests by (a) dilution in phosphate-buffered saline (PBS), (b) extraction of the water-soluble fraction with chloroform, or (c) freezing and thawing PBS-diluted yolks and testing the supernatant fluid. HI antibody titers from serum and extracted yolk were similar except during the initial 2 weeks, when yolk antibody levels were low or absent. Chloroform-extracted yolks were suitable material for the HI, ELISA, and ID tests. Heat inactivation of the chloroform-extracted yolk had no effect on titers.     

鸽新城疫四元材料蜂胶佐剂灭活苗免疫期试验研究

采用四批四元材料混合病毒（鸡胚尿囊液、羊水、尿囊膜、羊膜）制备的鸽新城疫（No）蜂胶佐剂灭活疫苗（0701、0702、0703、0704）分别免疫30日龄非免疫健康鸽,不定期采血,连续检测HI抗体的动态变化,这四批疫苗免疫后5d均可检测出抗体,14d达到最高峰（平均为11．31log2）,6个月的平均HI抗体滴度均在6．4log2以上。因此,该苗对鸽的ND免疫保护期至少为6个月。     

SPF鸡感染网状内皮组织增生症病毒后血清和卵黄的抗体反应相关性比较

为进一步研究采用卵黄抗体检测代替血清抗体检测的可行性,采用已建立的卵黄抗体ELISA检测方法,比较同一时期卵黄抗体与血清抗体的相关性。人工感染23周龄无特定病原体（SPF）鸡,每周采集全血分离血清,每天收集种蛋,ELISA方法检测血清、种蛋中的REV抗体,并进行比较,结果表明：攻毒后第2周开始血清抗体和卵黄抗体呈阳性,并达到峰值,之后抗体水平缓慢下降,两者具有相似的消长规律;对同一时期的卵黄抗体和血清抗体S/P比值进行统计学比较,P值小于0.05,相关系数为0.931,表明两者差异性不显著,相关性很好;阴阳性符合率比较,阳性符合率为97.8%,阴性符合率为100%,总体符合率为98.4%,阴阳性复合率很高。试验证明,同一时期的卵黄抗体和血清抗体的相关性很好,可用卵黄抗体检测方法代替血清抗体检测,从而为监测SPF鸡群感染REV提供新的技术手段。     

胶体金法与酶联免疫吸附测定法检测猪瘟抗体的比较

为比较胶体金法与ELISA法检测猪瘟抗体的符合率,以了解胶体金法的特异性与敏感度,用胶体金法和ELISA法平行检测受检猪血清标本猪瘟抗体滴度.结果表明,胶体金法和ELISA法检测猪瘟抗体的结果符合率为86.6％,胶体金法较ELISA法敏感度、特异度低,用胶体金法检测猪瘟抗体滴度存在一定程度的漏检率及误诊率,只能初步筛查猪瘟抗体.具有一定技术力量的县级兽医实验室使用ELISA法检测猪血样的猪瘟抗体滴度更为合适,对于胶体金法筛查阴性的猪血样,建议用ELISA法复检以防漏检.     

Prevalence and incidence of Newcastle disease and prevalence of Avian Influenza infection of scavenging village chickens in Timor-Lesté

A longitudinal study to monitor prevalence and incidence of antibodies against Newcastle disease (ND) virus and prevalence of antibodies against Avian Influenza (AI) virus in scavenging village chickens was conducted in 20 villages within 4 districts of Timor-Lesté. A total of 3600 blood samples was collected from 1674 individual birds in 300 household chicken flocks during three sampling periods (December 2008-February 2009, March-May 2009, and June-August 2009). The mean interval between household visits was 101.6±1.9 days. None of the birds enrolled in the study was vaccinated against ND or AI. A haemagglutination inhibition (HI) test was used to determine antibody titres against ND virus and a competitive ELISA and HI tests were used to detect antibody against AI virus. The bird-level ND seroprevalence pooled across all samplings (adjusted for clustering by households) was 4.4% (95% CI 3.5-5.2). The bird-level ND seroprevalence in each of the three sampling periods (adjusted for clustering by household) was 3.0% (95% CI 2.0-4.0), 6.6% (95% CI 5.1-8.0) and 3.6 (95% CI 2.5-4.6), respectively. A total of 12.6% individual birds tested ND seropositive at least once over the total study period (95% CI 10.5-14.7). The flock-level ND seroprevalence (at least one bird tested had antibodies against ND virus) pooled across all samplings was 15.9% (95% CI 13.5-18.3). A total of 35.3% flocks had a minimum of one bird being ND seropositive at least once over the study period. The bird-level incidence rate for the period between the first and the second sampling and between the second and the third sampling was 5.6 (95% CI 4.1-7.5) and 0.5 (95% CI 0.5-3.8) per 10,000 bird-years-at-risk, respectively. A total of 1134 serum samples from the last sampling period between June and August 2009 was tested for antibodies against AI virus. Only 4 samples tested Influenza A positive, indicating a bird-level seroprevalence level for Influenza A of 0.4% (CI 0.0-0.7%). These Influenza A positive samples were further tested for HI antibodies against AI virus subtypes of H5N1, H5N3, H7N3 and H9N2, but all tested negative, suggesting that the influenza antibodies in those four birds resulted from exposure to low pathogenic AI viruses of different H subtypes. Our results indicate that village chickens in Timor-Lesté are exposed to ND virus; there was a higher risk of infection during the early months of 2009 than either immediately prior or subsequent to this. No evidence of infection of village chickens with H5, H7 or H9 AI viruses was detected in this study.