广东省猪群口蹄疫免疫抗体水平调查

采集广东省不同地区11个猪场的不同类型猪的血清样品3 108份,采用液相阻断-酶联免疫吸附法,以口蹄疫结构蛋白抗体滴度作为评估疫苗效力的指标。本试验共采集种公猪血清样品77份,结果显示平均抗体滴度为(1.859 1±0.078 1,1∶72);仔猪血清样品514份,平均抗体滴度为(1.793 3±0.027 9,1∶62);经产母猪血清样品604份,平均抗体滴度为(1.967 2±0.024 2,1∶92);后备母猪血清样品有1 913份,平均抗体滴度为(1.790 8±0.015 2,1∶61)。从统计结果来看,经产母猪的免疫状态是最好的,但总的来说,猪群的整体免疫水平不高,免疫形势不容乐观,口蹄疫的防治水平仍须提高。     

注射口蹄疫疫苗对种公牛精液品质的影响研究

[目的]研究注射口蹄疫疫苗对种公牛精液品质的影响。[方法]随机选择6头种公牛,并采其精液进行检测,用比较方法研究。[结果]注射双价灭活疫苗前精液量6.8ml,鲜精活率70%,精液密度17.3亿/mL,冻后活率39.7%冻精数414.8剂,精子畸形率14.2%。注射双价疫苗之后精液量4.3 mL,鲜精活率6.5%,精液密度12.7亿/mL,冻后活率34.8%冻精数162.3剂,精子畸形率18%。[结论]注射疫苗后,种公牛的精液品质也随之下降,精液量、精子密度和原精活率注射后较注射前极显著降低,认为注射口蹄疫疫苗对种公牛的精液品质产生较大影响。     

进境动物及动物产品传带SAT型口蹄疫的风险评估

SAT型口蹄疫(foot and mouth disease,FMD)已从传统流行区域非洲大陆传播至西亚、中东地区,对我国畜牧业发展构成了潜在威胁。为评估SAT型FMD跨境传入风险,采用定性评估方法,对进境动物及动物产品传带SAT型FMD的风险进行了综合评估。结果表明,从疫区进口相关动物及动物产品传入SAT型FMD的风险高,因此需采取严格的风险管理措施,将FMD传入风险降低至我国可接受的水平。     

The North American Animal Disease Spread Model: a simulation model to assist decision making in evaluating animal disease incursions

The North American Animal Disease Spread Model is a stochastic, spatial, state-transition simulation model for the spread of highly contagious diseases of animals. It was developed with broad international support to assist policy development and decision making involving disease incursions. User-established parameters define model behavior in terms of disease progression; disease spread by animal-to-animal contact, contact with contaminated personnel or equipment, and airborne dissemination; and the implementation of control measures such as destruction and vaccination. Resources available to implement disease control strategies, as well as the direct costs associated with these strategies, are taken into consideration. The model records a wide variety of measures of the extent of simulated outbreaks and other characteristics. The graphical interface and output visualization features also make it a useful tool for training and preparedness exercises. This model is now being used to evaluate outbreak scenarios and potential control strategies for several economically important exotic animal diseases in the United States, Canada, and elsewhere. NAADSM is freely available via the Internet at http://www.naadsm.org.     

Evaluation of the transmission risk of foot-and-mouth disease in Japan

The transmission risk of foot-and-mouth disease (FMD) in Japan was evaluated using a mathematical FMD transmission model. The distance-based transmission rate between farms, which was parameterized using the FMD epidemic data in 2010 in Japan, was used to calculate the local-level reproduction numbers—expected numbers of secondary infections caused by one infected farm—for all cattle and pig farms in the country, which were then visualized as a risk map. The risk map demonstrated the spatial heterogeneity of transmission risk in the country and identified risk areas with higher possibility of disease spread. This result suggests that, particularly in high-risk areas, it is important to prepare for the smooth and efficient implementation of control measures against FMD outbreaks.     

猪O型口蹄疫灭活疫苗免疫效果评估

为了考察市售高效灭活疫苗与政府采购疫苗免疫效果之间差异分别选取了两家疫苗公司生产的政府采购疫苗和高效灭活疫苗,分别在4个猪场展开免疫效果评估。4个猪场按照相同的免疫程序进行免疫,分别采集免疫前、加强免疫后30 d、加强免疫后60 d的血清,用O型口蹄疫抗体液相阻断ELISA试剂盒进行抗体检测。结果表明,加强免疫后30 d,抗体平均效价依次为1∶196.9、1∶251.9、1∶256.0、1∶243.8。高效灭活苗与政府采购疫苗在同样的免疫程序和免疫剂量下,同一时间点其抗体水平效价差异不显著;但免疫副反应方面,高效灭活疫苗比政府采购疫苗低,且差异极显著。     

牛O型、亚洲Ⅰ型口蹄疫疫苗不同免疫次数免疫后群体抗体合格率比较

本研究选取沈阳地区饲养管理正规的牛规模场,采用液相阻断ELISA试验方法测定牛血清样品中O型-亚洲Ⅰ型口蹄疫抗体水平,并计算免疫抗体的群体合格率。用O型-亚洲Ⅰ型二价苗一免、二免、三免的牛在免后28d时牛O型-亚洲Ⅰ型口蹄疫免疫抗体群体合格率研究结果表明,O型口蹄疫免疫抗体群体合格率分别为82.5%、100%、100%;亚洲Ⅰ型口蹄疫免疫抗体群体合格率分别为57.5%、97.5%、97.5%。一免后O型和亚洲Ⅰ型口蹄疫免疫抗体群体合格率下降速度均较快,一免后60dO型免疫抗体群体合格率降到72.5%,免后80d时O型、亚洲Ⅰ型口蹄疫免疫抗体群体合格率分别降为47.5%、12.5%。二免以上的牛口蹄免疫抗体群体合格率在28～120d内均较一免组高,而且抗体持续时间也长,三免后120d时O型、亚洲Ⅰ型口蹄疫免疫抗体群体合格率仍高达77.5%、75%。     

猪A型口蹄疫病毒特异性IgA抗体间接ELISA检测方法的建立与初步应用

为建立一种检测口蹄疫病毒（foot-and-mouth disease virus,FMDV）特异性IgA抗体的检测方法,本研究以原核表达系统表达纯化的FMDV结构蛋白VP1作为包被抗原,以鼠抗猪IgA单克隆抗体为二抗,辣根过氧化酶标记的羊抗鼠IgG抗体为三抗,建立猪A型FMDV特异性IgA抗体间接ELISA检测方法。确定抗原包被浓度为3.50 μg/mL,二抗与三抗的最佳稀释度为1∶10 000,二抗和三抗作用时间均为30 min。所建立的方法与抗猪瘟病毒、猪繁殖与呼吸道综合征病毒等病原的特异性IgA抗体间无交叉反应,A型口蹄疫感染样品的阳性检出率在90%以上,批内和批间重复性试验的变异系数介于3.16%~9.76%。该方法为监测FMDV特异性IgA抗体水平变化规律及猪的黏膜免疫效果评价及口蹄疫的早期诊断提供了一种新方法。     

口蹄疫病毒结构蛋白P1基因植物表达载体构建及鉴定

通过RT-PCR克隆了口蹄疫病毒(FMDV)全长P1基因,然后与植物的表达盒融合构建了重组质粒pB1131SP1、pBIP1和pBIAP1,并将质粒转化到根癌农杆菌LBA4404和EHA105中,获得了植物双元表达载体。     

Development and Primary Application of Indirect ELISA Method for Detecting the IgA Antibody against Foot-and-mouth Disease Virus Type A in Porcine

An indirect ELISA for detecting the IgA antibody against porcine foot-and-mouth disease virus (FMDV) type A was developed by using purified FMDV structural protein VP1 as coating antigen, mouse anti-pig IgA monoclonal antibody as second antibody and HRP-conjugated goat anti-mouse IgG as third antibody.The concentration of coating antigen was optimized as 3.50 μg/mL,the dilution and reaction time of second antibody and third antibody were optimized as 1:10 000 and 30 min, respectively.There was no cross-reactivity with anti-CSFV, PRRSV and other pathogen specific IgA antibodies.The positive detection rate of FMDV type A infectedsamples was above 90%.The coefficient variation of intra-and inter-assay was ranged from 3.16% to 9.76%.The ELISA method described in this study was proved to be specific and rapid for the detection of FMDV specific IgA antibody.It was potential to be applied for detection the level of FMDV specific IgA and evaluate the effect of mucosal immunity.Besides,it provided a new method for clinical diagnosis of foot-and-mouth disease.