Oral Infection of Weanling Foals with an Equine Isolate of Lawsonia intracellularis,Agent of Equine Proliferative Enteropathy

Background: Equine proliferative enteropathy (EPE) is an emerging disease of weanling foals. Objectives: Describe clinical, hematologic, biochemical, serologic, molecular, and ultrasonographic findings in foals experimentally infected with Lawsonia intracellularis. Animals: Eight foals. Methods: Recently weaned foals were assigned to either the challenge (n = 3), the sentinel (n = 3), or the control (n = 2) group. Foals were experimentally challenged via intragastric inoculation of 3 × 10¹⁰L. intracellularis organisms grown in culture. Each experimentally infected foal was housed with a sentinel foal in order to assess feco‐oral transmission. All foals were monitored daily for the development of clinical abnormalities and were weighed once weekly for the duration of the study (90 days). Abdominal ultrasound examination was performed weekly. Feces were collected every other day for 60 days, then weekly for an additional 30 days for the quantitative molecular detection of L. intracellularis. Blood was collected weekly for hematologic, biochemical, and serologic analysis. Results: Only challenged foals developed transient clinical signs of EPE consisting of anorexia, lethargy, fever, loose feces, and peripheral edema. Two challenged foals developed transient hypoalbuminemia. Fecal shedding of L. intracellularis was first detected in the challenged foals between days 12 and 18 postinoculation and lasted for 7–21 days. Seroconversion was documented in all challenged foals and in 1 sentinel foal. The remaining sentinel and control foals remained unaffected. Conclusions and Clinical Importance: Clinical EPE of variable severity was induced in all foals infected with L. intracellularis. Furthermore, L. intracellularis can be transmitted via the feco‐oral route to susceptible herdmates.     

Use of serology and polymerase chain reaction for the rapid eradication of small ruminant lentivirus infections from a sheep flock: A case report

A SRLV-free sheep flock incurred infection which led to an SRLV infection rate of over 50% of the ewes (34/64) within a 30 months period, indicating that environmental conditions were favourable to transmission. An intensive regimen of sampling at short intervals and testing for SRLV antibodies and proviral DNA combined with strict management was implemented for the entire flock, lambs and yearlings included. This resulted in eradication of the infection within two testing and culling rounds with a 3 months interval. The additional value of the proviral DNA detection by PCR in identifying infected animals was clear in that nine infected animals were found that would have been missed if tested by serology alone. PCR also saved two lambs from being culled; they were sero-positive probably due to maternal antibodies, but not infected.     

C型口蹄疫病毒型特异性抗原的表达与鉴定

[目的]为C型FMDV型特异性多克隆抗体、单克隆抗体的制备和FMDV定型提供理论依据。[方法]以含有C型口蹄疫病毒（FMDV）结构蛋白基因VP1的重组质粒pGEM—CP1为模板,设计特异性表达引物,扩增VP1及其c端编码区。对C型口蹄疫病毒VP1及其c端进行原核表达,并测定反应原性。利用纯化的C型VP1及其C端融合蛋白建立间接EHSA,分别对0、A、C、Asia1四型豚鼠阳性血清进行检测,确定C型VP1及其C端与其他3型FMDV抗体的型间交叉反应性。[结果]构建了pPR0-CVP1、pPR0-CVP1c重组原核表达质粒,实现了C型口蹄疫病毒VP1及其C端的高效表达,目的蛋白的分子量大小分别为33kD和20kD。Westernblot显示,VP1及其C端融合蛋白均可与对应血清型的豚鼠阳性血清反应。C型VP1及其C端与其他血清型的FMDV阳性血清均未发生交叉反应,且以VP1C端的型特异性最好。[结论]获得了C型FMDV特异性抗原。     

小西葫芦花叶病毒(ZYMV)抗血清制备及检测技术研究

从小西葫芦黄化花叶病毒(ZYMV)免疫的母鸡蛋卵黄和兔抗血清中分别提取免疫球蛋白IgY和IgG,用多种血清学方法进行检测。结果表明,免疫鸡和兔25d后,鸡蛋卵黄IgY和兔抗血清的效价分别达到1/64和1/512。在琼脂扩散试验中,当抗体稀释28倍时,与抗原反应无明显沉淀线。在胶乳凝集试验中,抗体稀释210倍时,与抗原反应无明显凝集物。ELISA法以辣根过氧化酶标记抗体IgY和IgG,用双抗夹心法成功地检测出了ZYMV,当抗体稀释106倍时,与抗原反应仍呈阳性。免疫电镜方法检测ZYMV,较一般血清学方法可多捕捉50倍的病毒颗粒。     

安徽省猕猴桃溃疡病菌鉴定

１９９０年春在岳西的双丰、龙井猕猴桃上首次发现一种新的猕猴桃溃疡病,１９９１年春严重发生,造成很大损失。作者于该园病枝、叶部分离得８个菌株,经致病性测定后进行了细菌学性 包括菌体形态学、培养性状、生理生化特性、血清学、特殊酶测定等研究,并以菌株ＫＷ１１作对比,结果表明,所测的安微菌株的细胞学性状基本与ＫＷ１１相似,帮我省猕猴桃溃疡病病原细胞也为Ｐｓｅｕｄｏｍｏｎａｓ ｓｙｒｉｎｇａｅ Ｐｖ。ａｃｔ     

动物布鲁氏菌病实验室检测技术研究进展

布鲁氏菌病是由布鲁氏菌引起的人畜共患传染病,对我国畜牧业生产和公共卫生安全造成严重的威胁。科学准确诊断是布鲁氏菌病防控的重要技术依据,然而布鲁氏菌病的检测和确诊一直以来都并非易事,常常需要通过多种检测结果的综合分析,因此发展敏感性高、特异性好的布鲁氏菌的检测技术十分重要。总结并分析了近年来布鲁氏菌检测技术基础研究和临床应用研究方面的最新进展,结合国家动物布鲁氏菌病参考实验室工作经验,对各类检测方法的优缺点和适用范围进行了分析,旨在为动物布病诊断技术的选择和推广应用提供理论和实践依据,为动物布鲁氏菌诊断技术的研究提供方向性思考。     

Mycobacterium bovis prevalence affects the performance of a commercial serological assay for bovine tuberculosis in African buffaloes

The endemic presence of bovine tuberculosis (BTB) in African buffaloes in South Africa has severe consequences for BTB control in domestic cattle, buffalo ranching and wildlife conservation, and poses a potential risk to public health. This study determined the BTB prevalence in free-ranging buffaloes in two game reserves and assessed the influence of the prevalence of mycobacterial infections on the performance of a commercial cattle-specific serological assay for BTB (TB ELISA). Buffaloes (n = 997) were tested with the tuberculin skin test and TB ELISA; a subset (n = 119) was tested longitudinally. Culture, PCR and sequencing were used to confirm infection with M. bovis and/or non-tuberculous mycobacteria (NTM). Prevalence of BTB, but not NTM, influenced the TB ELISA performance. Multiple testing did not increase test confidence. The findings strongly illustrate the need for development of novel assays that can supplement existing assays for a more comprehensive testing scheme for BTB in African buffaloes.     

High Seroprevalence Against Lawsonia intracellularis Among Adult Horses in Belgium

Lawsonia intracellularis (LI) is an obligate intracellular gram-negative rod causing equine proliferative enteropathy (EPE). Occasional cases of EPE have been reported in foals living in Belgium, but the seroprevalence of equine LI in this country is unknown. The target population included clinically healthy adult horses, whose blood samples were collected and analyzed for specific IgG antibodies against LI using a blocking enzyme-linked immunosorbent assay test. The results were expressed as percentage of inhibition (PI). Samples that had a PI <20% were judged as negative, those between 20 and 30% as inconclusive, and those >30% were considered positive. A total of 356 blood samples were analyzed with 352 horses (98.8%) testing positive, 2 horses (0.6%) testing negative, and 2 horses (0.6%) showing inconclusive results. The large percentage of seropositive samples obtained in this study confirms a widespread exposure of Belgian horses to LI.     

甘薯病毒病检测技术研究进展

简要概述了侵染甘薯的羽状斑驳病毒(SPFMV)、潜隐病毒(SPLV)、轻斑驳病毒(SPFMMV)、退绿矮缩病毒(SPCSV)、脉花叶病毒(SPVMV)等10余种病毒种类;着重综述了检测甘薯病毒常用的生物学、血清学、分子生物学等几种主要检测技术的原理和特点。生物学方法是依据病毒侵染后在甘薯或指示植物上的外观症状进行识别,但检测速度慢,易受季节限制;血清学技术是利用病毒外壳蛋白的抗原性,据特异性的抗体抗原免疫学反应检测病毒存在,但制备抗血清需时间长,对含量少和无蛋白外壳的病毒无法检测;分子生物学方法是以核酸为基础,通过检测病毒核酸来证实病毒的存在,该技术具有灵敏度高、特异性强、适应范围广等特点。