非洲猪瘟病毒K196R基因实时荧光定量PCR检测方法的建立

为建立一种准确、特异、高效、快速的非洲猪瘟病毒定量检测方法,本研究根据非洲猪瘟病毒(African swine fever virus, ASFV)早期表达基因K196R的基因序列,设计了TaqMan荧光定量PCR引物及探针,通过优化退火温度、引物及探针浓度,建立了快速检测ASFV的TaqMan荧光定量PCR检测方法。结果表明,该方法选择的引物具有高度灵敏性和特异性,以构建的重组质粒为标准品建立的TaqMan荧光定量PCR方法的标准曲线具有良好的线性关系(R~2=0.998),对ASFV核酸最低检测下限为1.3拷贝,且与猪伪狂犬病病毒、猪细小病毒、猪圆环病毒2型等多种病原不存在交叉反应。本研究建立的K196R基因实时荧光定量PCR检测方法为非洲猪瘟疫情提供了一种新型、灵敏和特异的早期检测方法。     

基于E184L基因的非洲猪瘟病毒实时荧光定量PCR检测方法的建立

非洲猪瘟(ASF)是由非洲猪瘟病毒(ASFV)感染引起的一种高度接触性传染病。由于ASFV的感染机制极为复杂,基因型多,至今尚无有效疫苗用于防控,防止该病暴发主要依赖于早期快速诊断和控制。为建立一种高效快速、特异的ASFV检测方法,根据ASFV的E184L基因序列,设计了TaqMan荧光定量PCR引物及探针,建立了检测ASFV的TaqMan荧光定量PCR方法。结果表明,该方法设计的引物具有高度特异性,以构建的重组质粒为标准品建立的TaqMan荧光定量PCR方法的标准曲线具有良好的线性关系,线性相关系数为0.992,对ASFV核酸最低检测限为1.51拷贝,且与伪狂犬病病毒、猪细小病毒、猪圆环病毒2型等不存在交叉反应。建立的基于ASFV E184L基因实时荧光定量PCR检测方法能够快速、准确、特异地对ASFV核酸进行定量分析,丰富了ASFV的检测方法。     

猪繁殖与呼吸综合征病毒TaqMan荧光定量RT-PCR方法的建立与应用

为快速检测猪繁殖与呼吸综合征病毒(PRRSV),本研究针对PRRSV的N蛋白基因保守序列,设计特异性引物和TaqMan探针,以体外转录的RNA作为标准品,设计并优化了检测PRRSV的TaqMan荧光定量PCR方法。应用该方法检测其它主要猪病病原,结果均呈阴性;针对PRRSV阳性RNA的检测灵敏度可以达到10拷贝,比常规PCR灵敏10倍～100倍;结果表明,本实验建立的PRRSV TaqMan荧光定量PCR方法具有良好的特异性、敏感性和重复性。应用建立的方法测定攻毒猪血清中病毒的含量,免疫攻毒组和非免疫攻毒组在第7 d血清中病毒的载量差异不显著,而在第14 d差异显著,免疫攻毒组猪血清中病毒载量明显低于未免疫组。     

用荧光定量RT-PCR方法检测猪瘟病毒

为了建立能特异检测不同基因型猪瘟病毒(Classical swine fever virus,CSFV),同时又能区分其他瘟病毒的基因检测方法,本实验针对CSFV基因组5′端非编码区设计并合成了简并引物和TaqMan探针,在优化反应条件的基础上,成功地建立了特异检测CSFV的荧光定量RT-PCR检测方法。再以已知滴度的CSFV石门株血毒总RNA反转录产物建立标准品,该标准品可以用于定量临床样品中的CSFV滴度,所建立的荧光定量PCR方法可以灵敏地检测出10~(-0.82)个TCID_(50)病毒含量。最后用建立的方法对108份临床样品进行检测并同时进行病毒分离,荧光定量PCR方法检测出73份阳性样品且与病毒分离的符合率为100%,而常规RT-PCR只检测出54份阳性样品,表明本荧光定量RT-PCR法在检测猪瘟病料上具有潜在的应用价值。     

猪瘟病毒TaqMan实时荧光定量PCR的建立与应用

为了建立一种既能检测野毒,又能检测疫苗毒的猪瘟病毒TaqMan实时荧光定量PCR方法,经过对GenBank中所有瘟病毒属成员高度保守的5’端非翻译区序列比对分析后,设计出1对TaqMan Real-time RT-PCR引物、1条TaqMan探针和3条RNA标准品制备引物。猪瘟病毒石门毒株经RNA标准品制备引物RT-PCR扩增后,再经T7 RNA聚合酶体外转录制备包含检测目的片断序列的猪瘟病毒RNA标准品。通过最佳引物、探针浓度的筛选及反应条件的优化,建立了猪瘟病毒TaqMan实时荧光定量PCR检测方法。该方法批内及批间重复试验变异系数均低于2%,特异性试验仅能检测出猪瘟强毒及疫苗毒株,最低浓度检测极限为1 X 102 copies/μL,上机检测时间少于60 min,建立的标准曲线斜率(Slope)为:-3.97,截距(Intercept)为:47.41,相关系数(R2)为:0.999779。运用该方法对3份猪瘟临床组织样品及6家企业生产的5种细胞苗及2种脾淋苗进行定量检测,结果提示:临床病料含有的病毒拷贝数差异不大,而疫苗产品每头份含有的病毒拷贝数差异较大。所建立的方法具有特异、快速、灵敏、可重复性和线性关系好的特点,不仅适合于猪瘟临床样品的早期检测,也适用于疫苗生产过程中的质控及疫苗制品的效价评估。     

猪瘟病毒野毒株和兔化弱毒疫苗株复合实时荧光定量RT-PCR鉴别方法的建立

根据GenBank中的猪瘟病毒强毒和弱毒株基因组序列设计了1对针对猪瘟病毒的通用引物和2条分别针对猪瘟病毒强毒和猪瘟兔化弱毒疫苗株的特异性TaqMan水解探针，建立了一种能区分猪瘟病毒强毒和兔化弱毒疫苗株的复合实时荧光定量RT—PCR检测方法。结果显示，该方法能将我国大陆流行的不同基因亚群的猪瘟病毒强毒株与猪瘟兔化弱毒疫苗株完全区分开来，而不与其他猪源病毒发生非特异反应，分别可检测到初始模板中41．8和81．5个拷贝的病毒RNA，与已建立的复合RT-套式PCR的敏感性相近，两种方法对152份样品检测的符合率达96．9％～100％。通过对8份猪瘟兔化细胞疫苗效价的检测，证实本方法与兔体反应热测定法有一定的相关性，可用于猪瘟病毒强毒株和兔化弱毒疫苗的定量和鉴别检测。     

两种荧光定量PCR方法检测猪瘟病毒的比较及应用

根据猪瘟病毒（Classical swine fever virus,CSFV）5端非编码区保守区域,设计猪瘟病毒特异性的引物和探针,建立了基于SYBR Green和TaqMan探针的两种荧光定量PCR检测方法。灵敏性和特异性试验结果表明,两种方法能够特异性地检测出不同型的猪瘟病毒,而对同属的牛病毒性腹泻病病毒以及其它一些主要猪病病原检测结果均为阴性。两种方法对猪瘟病毒C株的检测下限均为101TCID50,均高于常规的套式PCR。用携带该基因片段的重组质粒为模板进行检测,SYBR Green方法的检测下限为3×100copies,比TaqMan探针方法更加灵敏（3×101copies）。应用建立的SYBR Green方法对2009年采集于浙江地区不同猪场的20份病猪样品进行CSFV检测,有8份样品为阳性,与套式PCR方法检测结果一致。进一步应用SYBR Green方法对不同感染阶段细胞内病毒RNA复制水平进行检测,与病毒滴度的结果基本一致。因此,本研究建立的SYBRGreen荧光定量PCR检测方法能够应用于组织和培养细胞中猪瘟病毒的检测。     

针对猪瘟病毒E2蛋白的实时荧光定量PCR方法的建立及应用

根据猪瘟病毒(Classical swine fever virus,CSFV)E2基因的保守序列,设计合成一套特异性引物和TaqMan探针,通过对反应体系和反应条件进行优化后,检测其特异性和灵敏性。结果显示,本研究建立的实时荧光定量PCR在101～108范围内线性相关系数为0.997,能够检测到相当于10 copies/μL的病毒核酸,比常规PCR检测方法敏感性强;采用建立的实时荧光定量PCR方法检验猪繁殖与呼吸综合征病毒、猪伪狂犬病毒和猪圆环病毒2型呈现阴性结果,特异性强;变异系数为0.09%～0.7%,小于1%,具有良好的重复性。本研究建立的猪瘟病毒实时荧光定量PCR方法为临床上猪瘟病毒的诊断和定量研究提供了重要的检测工具。     

荧光定量RT-PCR检测公猪精液和血液中猪瘟病毒载量

为快速检测规模化猪场猪瘟病毒(Classical swine fever virus,CSFV),本研究参考GenBank中登录的CSFV序列设计引物,利用实时荧光PCR技术,构建重组质粒作为阳性标准品,建立特异、敏感、重复性好的CSFV快速定量检测方法.同时建立标准曲线,用于对猪瘟病毒的定量分析.本方法对规模化猪场的100份抗凝血和50份公猪精液样品进行检测,常规PCR检出27份占18％,荧光定量PCR检出123份占82％.表明荧光定量RT-PCR方法在检测猪瘟样品中具有潜在的应用价值,同时可检测猪群中猪瘟病毒持续性感染的状态存在.     

TaqMan荧光定量PCR检测猪流行性腹泻病毒方法的建立与初步应用

根据GenBank中公布的猪流行性腹泻病毒Ⅳ基因序列,设计了一对特异性引物和探针,扩增长度为186bp的片段。以克隆Ⅳ基因的质粒作为阳性标准品,建立了一种快速检测猪流行腹泻病毒含量的TaqMan荧光定量PCR方法。该方法在10^9-10^1copies／μL范围内具有良好的线性关系,可检测到初始模板中10copies／μL的质粒DNA,以猪圆环病毒、猪乙脑病毒、猪瘟病毒、猪繁殖与呼吸综合征病毒、猪伪狂犬病毒和猪细小病毒为模板时,均检测不到荧光信号,而重复性实验中其变异系数均小于2％,表明此方法具有很好的特异性和重复性。应用此方法对采集的60份,陆床样品进行检测,其阳性检出率为92％,而用常规RT-PCR方法进行检测,阳性检出率仅为80％。表明荧光定量RT-PCR方法的敏感性明显高于常规PcR检测方法。     

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.     

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.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

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.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -