弯曲菌荧光定量PCR检测方法的建立及初步应用

根据弯曲菌16S rRNA基因的靶序列设计特异性引物和探针,对反应条件和试剂浓度进行优化,建立了快速检测鸡肉中弯曲菌的荧光定量PCR方法,并对其特异性、敏感性和重复性进行评价。该方法除了对弯曲菌有扩增曲线外,对其他常见食源性病原菌均未有扩增曲线,具有较好的特异性;弯曲菌的最低检测限为10 CFU/mL;重复性实验获得标准曲线相关系数为R2=0.999,批内可重复性变异系数在0.12%-2.1%之间,批间可重复性变异系数为1.7%。应用该方法对68份鸡肉样品检测弯曲菌阳性率为95.6%（65/68）,传统分离方法阳性率为89.5%（60/68）,两种方法的阳性符合率为89.7%。本研究建立的荧光定量PCR方法灵敏度高、特异性好、操作简单,大大缩短检测周期,可作为检测鸡肉样品中弯曲菌的手段,为鸡肉样品弯曲菌的流行病学调查研究提供新的工具。     

饲料中志贺氏菌的PCR快速检测方法的建立

为建立饲料中快速检测志贺氏菌的有效方法,本研究根据志贺氏菌(Shigella)侵袭性质粒抗原H基因(invasion plasmid antigen H,ipaH)设计了一对引物,PCR扩增片段长度为386bp。通过对引物的特异性检测发现,4株志贺氏菌的PCR结果均为阳性,12株非志贺氏菌的检测结果均未扩增出特异性片段。PCR对志贺氏菌纯培养物的检测灵敏度达120cfu/ml,检测快速、便捷。该方法操作简单、检验周期短、特异性和灵敏度高,能够快速地实现对饲料中志贺氏菌的检测和监控。     

应用PCR快速检测鸡滑液囊支原体的研究

根据鸡滑液囊支原体(MS)16S rRNA设计引物,对1株MS阳性株、5株临床分离鉴定的MS、2株鸡毒支原体、1株多杀性巴氏杆菌、1株沙门菌、1株大肠杆菌和1株金黄色葡萄球菌进行PCR扩增,结果显示所有MS均出现1 077 bp特异性扩增条带,其余非MS则均未扩增出特异性条带。敏感性测定结果表明,优化的PCR反应体系能检出MS的最低DNA量为1 pg。建立的PCR方法用于快速检测临床样品检测,对鸡肿胀跗关节腔内容物直接进行PCR检测,检出率为21.1%(32/152),显著高于病原分离方法的9.2%(14/152),具有良好的实际应用意义。     

用四重PCR检测方法检测产单核细胞李斯特菌

为了同时快速准确的检测产单核细胞李斯特菌以及是否为有毒力的产单核细胞李斯特菌,根据相关文献报道的四重PCR方法,针对该菌的种特异性基因inl A基因进行引物设计,扩增片段大小为800bp,结果应用该PCR法可特异性的扩增出目的基因片段,与GenBank上发表的序列同源性为97.3%。同时通过对毒力基因inlB,inlC和inlJ的检测用来判断菌株的相关毒力。而同一属的其他菌种无害李斯特菌(L.innocua),韦氏李斯特菌(L.welshimeri)均无特异条带,嗜水气单胞菌(J-1),产气荚膜梭菌(C57-13),大肠埃希菌(ATCC 25922),鼠伤寒沙门菌(C79-32),金黄色葡萄球菌(ATCC 25923)结果均为阴性。对临床上送检的23份样品进行四重PCR方法检测并同时与国家标准GB/T22429-2008食品中单核细胞增生李斯特氏菌的快速筛选检验中使用的检测方法进行比对,两种检测方法的结果完全符合,均检测出7份阳性样品。并且四重PCR法表明这7份阳性样品中的产单核细胞李斯特菌均携带有3种毒力因子(inlB,inlC和inlJ),因此该四重PCR法可用于快速鉴定是否是有毒力的产单核细胞李斯特菌,为有效预防控制产单核细胞李斯特菌污染提供技术支撑。     

羊梭菌病快速鉴别PCR方法的建立及初步应用

根据GenBank已公布的产气荚膜梭菌和腐败梭菌的α毒素基因序列,分别设计并合成针对2种α毒素基因的特异性引物,通过扩增条件的优化,建立快速鉴别产气荚膜梭菌和腐败梭菌的双重PCR方法。特异性试验显示,产气荚膜梭菌和腐败梭菌参考菌株均扩增出了相应的预期目的条带,而大肠埃希菌、沙门菌、金黄色葡萄球菌和链球菌则均未能扩增出相应条带。灵敏度试验结果显示,产气荚膜梭菌和腐败梭菌基因组DNA最低检测量分别为17.95pg/μL和1.261pg/μL。应用该方法对样品进行检测,其中5份为产气荚膜梭菌阳性。成功建立了特异性强、敏感性高的双重PCR方法,可以有效进行产气荚膜梭菌和腐败梭菌的快速鉴别,对羊梭菌病病原快速鉴定及流行病学调查具有重要意义。     

基于gyrB基因建立快速检测沙雷菌的PCR方法

选择gyr B基因作为靶基因设计特异性引物用于沙雷菌属的PCR检测,该特异性引物扩增产物的片段大小为279 bp。研究所选用的14株沙雷菌分别代表沙雷菌属的7个不同种。此外,2种沙门菌、2种克雷伯菌以及其他5种肠道菌用于进行引物特异性的验证。结果表明:扩增的条带与预期的扩增产物片段大小一致,而非沙雷菌属的其他9个种属均没有扩增条带;该方法检测沙雷菌的最低检测限为9.785 pg。通过对4株从蜜蜂中分离所得的黏质沙雷菌和3株从进口鱼粉中分离所得的居泉沙雷菌进行检测,结果均为阳性。研究表明,基于gyr B基因建立的PCR方法在沙雷菌属的检测中具有特异性强、快速和灵敏度高等特点。     

单抗酶联试剂盒与PCR方法快速检测沙门氏菌的比较

本文对单抗酶联试剂盒与PCR方法快速检测沙门氏菌进行了比较。将沙门氏菌与大肠杆菌以不同比例混合后 ,分别用ELISA和PCR法检测 ,在 1∶1 0 0的比例时 ,用这 2种方法均能检测出阳性样品 ;在 1∶1 0 0 0的比例时 ,用ELISA法检测为阴性 ,而用PCR法则能检测出。检测鲜牛奶、龙虾、虾仁、熟食制品等样品 ,2种方法的符合率达 97 6 %。对冻虾仁、人粪便样品的前增菌、选择性增菌、后增菌过程进行同步检测 ,在样品的前增菌液 ,直接ELISA法检测的OD值小于 0 5 ,而PCR法扩增能出现特异条带 ,经国标方法验证为阳性 ,证实PCR法的敏感性优于直接ELISA法 ,而在选择性增菌液和M 肉汤后增菌液中 ,2种方法均能检出阳性样品。     

空肠弯曲菌PEB1A蛋白的原核表达及间接ELISA方法的建立

为了建立检测血清中空肠弯曲菌（Campylobacter jejuni）抗体的间接ELISA方法,试验通过PCR扩增并克隆空肠弯曲菌PEB1A基因,构建原核表达载体pET32a-PEB1A,将该表达载体转化大肠杆菌BL21（DE3）感受态细胞,诱导表达获得约47 ku的可溶性目的蛋白,通过Western blotting证明所表达的重组蛋白具有良好的生物学活性。以纯化后的重组蛋白作为包被抗原,建立空肠弯曲菌抗体间接ELISA方法,对其特异性、敏感性、重复性进行检测。结果表明,本试验建立的空肠弯曲菌抗体间接ELISA检测方法临界值为0.3424,本方法仅与空肠弯曲菌阳性血清发生特异性反应,与其他抗血清无交叉反应,具有较强的特异性,批内、批间的重复性试验变异系数均<5%,具有较好的重复性和稳定性。该方法的建立可应用于血清中空肠弯曲菌抗体的快速检测,为进一步防制空肠弯曲菌腹泻提供依据。     

犬小孢子菌、石膏样小孢子菌、须毛癣菌多重PCR检测方法的建立及初步应用

宠物浅表皮肤真菌病主要由犬小孢子菌、石膏样小孢子菌、须毛癣菌感染引起。本研究根据3种真菌基因内转录间隔区(internal transcribed spacer,ITS)区域的序列差异设计4条引物,通过优化多重PCR反应条件,建立了一种可同时快速检测这3种真菌的多重PCR,同时对其特异性、灵敏性、重复性进行分析。结果显示,建立的多重PCR方法对犬小孢子菌、石膏样小孢子菌、须毛癣菌基因组DNA均可扩增出特异性预期片段,条带大小分别为286、596、188 bp;最低检测限(灵敏性)分别为12.6、8.8、13.6pg/μL;被检测的6份人工模拟样品扩增结果准确。应用该多重PCR方法检测27份人临床皮屑样品和43份宠物犬、猫毛发样品,结果显示阳性检出率分别为74.07%(20/27)和83.72%(36/43);采用常规真菌分离培养法从阳性样品中获得10株致病性真菌,分离率为17.86%(10/56);两种检测方法的种属鉴定结果表明多重PCR法优于常规方法。本研究建立的多重PCR检测方法简便、特异、灵敏,可同时对宠物浅表真菌病原作出快速诊断与鉴别。     

布鲁菌病多重PCR快速检测方法的建立及应用

根据GenBank中登录的布鲁菌(Brucella)omp31、bp26、omp10外膜蛋白基因序列,针对同一种病原,各设计合成了一对特异性引物,通过优化引物浓度组合,建立了检测布鲁菌472 bp、290 bp、162 bp片段的多重PCR快速检测方法。通过对该方法的特异性、敏感性和重复性试验,结果显示,该方法从布鲁菌标准菌株中扩增出了特异性的目的片段,而对大肠埃希菌等细菌的扩增结果均为阴性。经过对10倍倍比稀释的模板进行检测,多重PCR的敏感度为最低可检出1.1×10-3ng的DNA,在感染布鲁菌病奶牛乳汁模拟标本中最低可检出细菌数为80 cfu/mL。不同人员用该方法重复检测,结果均一致,表明重复性好。应用该方法对88份临床疑似布鲁菌感染的奶牛乳样进行了检测,结果检出17份阳性,阳性检出率约为19.3%。检测结果表明,该方法具有特异、敏感、重复性好等优点,可用于奶牛布鲁菌病的临床检测及流行病学监测等。     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Feline intracranial neoplasia: retrospective review of 160 cases (1985-2001)

The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.     

A brief history of the prevention of infectious diseases by immunisations

Infectious diseases have always been a terrible scourge for humans. The appearance of these plagues, as they were called without distinction, was generally connected to various conditions: asters, climatic changes or religious reasons. The concept of contagious, and then infectious, diseases came slowly. Variolation, i.e. transmission of ‘virulent’ matter to induce a natural disease and the immunity against it, was brought from Constantinople to England by Lady Montague, in 1721. This ‘variolation’ technique was also often performed in veterinary medicine against diseases like sheep-pox or pleuropneumonia. As ‘vaccination’ is the term generally accepted for ‘immunisation’, variolation can be the word designating such a technique. The second period of the history of immunisation began, in 1880, with the studies of Pasteur and his collaborators. A great number of bacterial vaccines were developed: dead, live but attenuated or only parts of pathogens. The viruses were produced in animals, then in eggs and at last, in tissue cultures. Second generation vaccines appeared with genetic engineering: recombinant vaccines, vector vaccines, nucleic acids vaccines, and markers vaccines, among others. These novel technologies can permit the development of new ones and improve the quality of the vaccines already existing.