A serological survey for Bhanja and tick-borne encephalitis viruses in sheep of eastern Slovakia

755 sheep from 41 farms in the districts of Trebisov, Michalovce, Humenné and Roznava in the East Slovakian region were investigated on the presence of antibodies to Bhanja (neutralization test) and tick-borne encephalitis (haemagglutination-inhibition test) viruses. In respective districts 2.2%, 0.4%, 1.7% and 26.7% of animals (total 5.3%) were found to be positive on Bhanja virus, 4.4%, 1.5%, 1.7% and 5.0% (total 2.6%) on tick-borne encephalitis (TBE) virus. The considerable infection rate in sheep with Bhanja virus in the district of Roznava (mean 26.7%-on one farm as high as 63.9% serologically positive animals) can be explained by the local occurrence of the tick Haemaphysalis punctata, the main vector of this virus in Europe. The serologic screening conducted indicates a low activity of natural foci of TBE in eastern Slovakia today, and confirms the existence of a natural focus of infection with Bhanja virus in the district of Roznava. Recent circulation of Bhanja virus is indicated by antibodies detected in several one-year-old sheep.     

Replication of tick-borne encephalitis (TBE) virus in Ixodes ricinus ticks

The influence of external factors on virus carriage of Ixodes ricinus ticks in laboratory and in nature was studied. In laboratory experiment, only one nymph was positive for the presence of virus on 120th day after metamorphosis. The virus titer was 10(2) mouse i.c. LD50/0.03 ml. Transmission experiments were negative. The nymphs were positive on 75th, 111th and 159th day after metamorphosis, always chilling in the field experiment. The titres of virus varied from the lowest detectable amount value to 10(3.6) mouse i.c. LD50/0.03 ml. The transmission of virus was positive in two cases.     

Occurrence of ixodid ticks--the main vectors of tick-borne encephalitis virus in urbanized territory

The influence of urbanization on ticks I. ricinus and I. persulcatus--the main vectors of tick-borne encephalitis virus is discussed on the basis of concrete examples. It has been revealed that under favourable conditions the populations of these tick species can exist for a long time not only in towns and new housing estates, but in the old residential districts as well. The necessity of studying the ecology of urban populations of ixodid ticks is pointed out.     

Experimental infection of ticks Ixodes ricinus with tick-borne encephalitis virus under different microclimatic conditions

The influence of environmental temperature and relative air humidity on the development of ticks Ixodes ricinus and their infection rate with tick-borne encephalitis virus was studied. It was found that the temperature influenced significantly the development of ticks, but it did not influence their infection rate. To the contrary, the relative air humidity influenced the infection rate. It is assumed that the intrinsic factors play a primary role in the infection of ticks, while extrinsic factors have a secondary role; they are probably important at border values only.     

Contribution to the serological diagnosis of sarcocystosis.

The importance of the IFA-test (Indirect Fluorescent Antibody Test) in the diagnosis of sarcocystosis in the intermediate host has been confirmed in the present paper. We assessed the time of the first appearance of serum antibodies in the intermediate host in mice inoculated experimentally with the species Sarcocystis dispersa. By means of the IFA-test, the first antibodies were found on day 20 p.i. Cross-reactions among antisera of S. dispersa and a heterologous antigen of S. cernae disclosed that the reaction was not species-specific, but genus-specific. In addition, we confirmed serologically that the antigenic structure of the genus Frenkelia was identical to that of the genus Sarcocystis, because the results of cross reactions obtained with the IFA-test were identical.     

Probability models of the rate of infection with tick-borne encephalitis virus in Ixodes persulcatus ticks.

A total of 3,254 adults of Ixodes persulcatus tick were collected in a taiga forest habitat situated in the Amgun river basin (Khabarovsk region, the Far East, USSR) and examined individually for the presence and amount of tick-borne encephalitis virus. The over-all proportion of infected ticks was 6.6% and it varied between 3.4% and 9.4% in the years 1982 to 1985. The amount of virus per tick was approximated by the gamma distribution determining a probability that the number of plaque-forming units (PFU) per tick is not greater than a selected value. The frequency distribution of infected ticks followed a model of the negative binomial distribution, enabling the estimation of probability of the occurrence of a given number of infected ticks in the area. However, the parameters of both probability models (i.e., the PFU content per tick, and the frequency of infected ticks) varied for particular years.     

Immune response of the long-tailed field mouse (Apodemus sylvaticus) to tick-borne encephalitis virus infection.

The immune response following infection with a virulent strain of Central European encephalitis (CEE) virus in a natural host, long-tailed field mouse (Apodemus sylvaticus L.) and white laboratory-bread ICR mouse, was compared. Viraemia was demonstrated in ICR mice after intraperitoneal infection with a dose of 10(5) LD50/0.5 ml. The virus titres were high in the spleen and, particularly, in the brain. In A. sylvaticus the virus was detected in the blood and spleen, but not in the brain. CEE virus multiplied in peritoneal macrophages from ICR mice, but not from A. sylvaticus. The infection induced a strong interferon response in both hosts. The natural killer (NK) cell activity increase was twice as high in A. sylvaticus compared to ICR mice. The neutralization antibodies appeared sooner in A. sylvaticus and reached higher titres in the early phases of infection.     

降香黄檀黑痣病菌的快速分子检测

<正>黄檀黑痣菌(Phyllachora dalbergiicola)能引起降香黄檀黑痣病,该病菌在世界分布十分广泛,且寄主植物种类繁多,除了降香黄檀以外,还可侵染大果紫檀、檀香紫檀等多种紫檀属植物。该菌所致病害会在寄主表面形成黑色凸起的盾片,严重影响寄主光合作用,致使其提前落叶~([1])。通过对黄檀黑痣菌进行早期检测,可以及时采取防治措施,控制病害的进一步发展。而黄檀黑痣菌是活体营养真菌,不能离体培养,使用常规的病害诊断技术     

基于环介导等温扩增技术快速诊断由Fusarium andiyazi引起的水稻恶苗病

水稻恶苗病是水稻上的重要病害,在我国各水稻主要种植区均有发生,造成水稻产量的严重损失。Fusarium andiyazi是近年来国外报道的水稻恶苗病的病原菌之一,本研究基于环介导等温扩增技术(loop-mediated isothermal amplification,LAM P),以F.andiyazi的TAT(trichothecene 3-O-acetyltransferase)基因为靶标设计并筛选出一套灵敏、特异的LAM P引物,建立了可快速诊断该病菌所引起的水稻恶苗病的LAMP检测技术。在等温条件下(64℃)只需进行核酸扩增反应80 min,反应前向体系中加入了金属离子指示剂HNB(羟基萘酚蓝),反应后即可肉眼观察反应产物颜色变化判断检测结果,阳性反应呈天蓝色,阴性呈紫色。该TAT-Fan-LAMP技术的最低检测灵敏度为100 pg·μL~(-1)。应用该技术成功地对南京江宁和镇江句容田间采集的由F.andiyazi引起的水稻恶苗病进行快速诊断。该LAMP检测技术的建立为F.andiyazi引起的水稻恶苗病的诊断提供了简便快速的新技术。     

Evaluation of an enzyme immunoassay for the detection of the insect growth regulator fenoxycarb in environmental and biological samples

A competitive enzyme-linked immunosorbent assay (ELISA) for fenoxycarb was adapted for quantitative detection of this insect growth regulator in various environmental, agricultural, food and biological matrices. Environmental samples were taken from soil and surface waters in Hungary. The ELISA enabled fenoxycarb detection in surface waters in the 1.1-125 ng ml(-1) concentration range without sample cleanup. In contrast, soil produced a strong matrix effect due to humic acids and other soil components. Several fruit homogenates and commercial fruit juices (eg apple, pear, grape) were analyzed by the ELISA. The assay was found to be suitable for analysis of fenoxycarb in fruit juices diluted 1:40. Biological samples included insect, fish and bovine tissues. The ELISA was applied to detect fenoxycarb in various biological matrices from larvae of the silkworm, Bombyx mori L. The assay proved useful for the analysis of haemolymph diluted 1:10 or at higher dilutions. Fat body and whole body homogenates, however, caused severe matrix effects. Fenoxycarb was detected in liver homogenates (diluted 1:40) from fish treated with various doses of fenoxycarb, and the concentrations determined correlated with the applied doses. The method was used to analyze spiked bovine urine samples diluted 1:10 or at greater dilutions. Fenoxycarb content determined by the ELISA in water and fruit juice samples was validated using GC-MS with solid-phase microextraction (SPME) sample preparation. The results of these studies demonstrated both the value and limitations of the assay when used for monitoring fenoxycarb in environmental, food and biological samples.     

快速检测马铃薯干腐病病原接骨木镰孢的环介导等温扩增技术

 本研究基于环介导等温扩增技术(loop-mediated isothermal amplification, LAMP),建立了一种快速、准确和灵敏的接骨木镰孢的检测技术。通过比对接骨木镰孢与其近源种之间的候选靶标序列,选取TEF1-α(translation elongation factor 1-α,翻译延伸因子)基因作为靶标,设计并筛选出一套对该病原菌具有种特异性的LAMP引物,建立了检测接骨木镰孢的 LAMP 体系。该体系在反应前加入染料羟基萘酚蓝(hydroxynaphthol blue,HNB),经62℃恒温反应70 min之后,可根据肉眼观察到的反应物的颜色判定结果。特异性分析结果表明,仅接骨木镰孢的DNA经检测后呈天蓝色的阳性反应,而其他供试菌株的DNA均呈紫色的阴性反应。该方法对DNA的最低检测限为100 pg·μL^-1。在采自内蒙古和黑龙江的28份马铃薯干腐病疑似病害样本中,检测到14份阳性样品。该方法的建立为接骨木镰孢的检测及其所致病害的诊断提供了快捷准确的技术。     

湖北和安徽省油菜病毒病调查和病毒血清鉴定

2003年秋至2005年春2个油菜生长季分别到湖北和安徽2省12县市油菜产区进行病毒病发病情况调查,除局部地区和地块发病率达到20%～40%,多数大面积油菜发病率在0.1%以下。应用间接酶联免疫吸附法检测258份病害样品,TuMV占样品总数的90.7%,CMV占样品总数的8.9%,ORMV占样品总数的0.8%。