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Search Results: 1 - 10 of 15399 matches for " virus detection "
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New and Emerging Viruses of Blueberry and Cranberry
Robert R. Martin,James J. Polashock,Ioannis E. Tzanetakis
Viruses , 2012, DOI: 10.3390/v4112831
Abstract: Blueberry and cranberry are fruit crops native to North America and they are well known for containing bioactive compounds that can benefit human health. Cultivation is expanding within North America and other parts of the world raising concern regarding distribution of existing viruses as well as the appearance of new viruses. Many of the known viruses of these crops are latent or asymptomatic in at least some cultivars. Diagnosis and detection procedures are often non-existent or unreliable. Whereas new viruses can move into cultivated fields from the wild, there is also the threat that devastating viruses can move into native stands of Vaccinium spp. or other native plants from cultivated fields. The aim of this paper is to highlight the importance of blueberry and cranberry viruses, focusing not only on those that are new but also those that are emerging as serious threats for production in North America and around the world.
Chronic hepatitis B liver disease in patients living in the Amazon region: S gene mutations and genotypes characterization  [PDF]
Deusilene Vieira, Marie Gauthier, L. D. de Figueiredo Nicolete, Alcione Oliveira dos Santos, Carina Picelli, Eduardo Honda, Glaucia Paranhos-Baccalà, Guy Vernet, Juan Miguel Villalobos Salcedo
World Journal of Cardiovascular Diseases (WJCD) , 2013, DOI: 10.4236/wjcd.2013.38080
Abstract: The Amazon region is considered to be a high endemic area for Hepatitis B Virus (HBV) infections, Rondônia state having the highest prevalence. The aim of this study was to identify molecular genotypes and mutations in the S gene region of HBV viral genomes from 20 patients using a DNA microarray. Results: Serological tests showed that 88% of patients were HBeAg negative, 82% had anti-HBe antibodies and 33% were co-infected with Hepatitis Delta Virus. Sixteen percent of the patients were considered cirrhotic, and 11% have been transfused. The microarray technique identified the genotypes A (4 patients), D (7 patients) and F (7 patients) in 18 samples. Mutations were detected in all 3 genotypes and, overall, A159G, which has been associated with a reduced antigenicity of the virus, was detected most frequently. In genotype A, G119E was the most frequently detected mutation followed by mutations A159G, F134Y, W172C, Y161F and T143S. A159G was detected in all genotype D and F samples followed by mutations T143S, Y161F, N131T, T114S and G119E in genotype D and mutations T143S, Y161F, N131T, T114S and G119E in genotype F. Conclusion: The analysis of mutations repartition among genotypes suggests that some of them are preferentially or exclusively associated with genotype A, D or F. This type of tool is adapted for clinical and therapy monitoring of patient as well as for molecular epidemiology research on HBV.
Rapid detection of wheat yellow mosaic virus by reverse transcription loop-mediated isothermal amplification
Zong-Ying Zhang, Xiao-Jun Liu, Da-Wei Li, Jia-Lin Yu, Cheng-Gui Han
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-550
Abstract: Wheat yellow mosaic is one of the most devastating soil-borne diseases of winter wheat (Triticum aestivum L.). It was first reported in Japan in the 1920s and China in the 1960s [1,2], and then spread continually in Japan and China [3,4]. According to the statistical data, the disease area was more than 666,700 hectares in the 1990s, the yield loss was estimated to range between 20-40% and could be up to 70-80% during a serious year, even 100%.Wheat yellow mosaic virus (WYMV), the causal agent of wheat yellow mosaic, belongs to the genus Bymovirus within the family Potyviridae. It is a soil-borne pathogen and is transmitted by the fungus-like organism Polymyxa graminis [5]. The genome of WYMV is comprised of two (+) single-stranded RNAs, RNA1 encodes for coat protein (CP) and six others: P3, 7 K, nuclear inclusion protein a (NIa), nuclear inclusion protein b (NIb), cytoplasmic inclusion protein (CI), 14 K; RNA2 encodes for a polyprotein that contains 28-kDa and 72-kDa proteins [6,7].Concerning virus detection, several methods are used commonly to detect WYMV. ELISA is a reliable method for detecting WYMV and suitable for high-throughput samples [8-10]; RT-PCR is the most conventional method to detect RNA virus [11,12] and western blotting detects the target protein for further confirmation [13-16]. However, the sensitivity of ELISA might not be sufficiently high to detect low concentrations of WYMV, and virus-specific antiserum is required. WYMV can serologically cross-react with wheat spindle streak mosaic virus [17], and RT-PCR is not perfect either.Novel nucleic acid amplification methods, loop-mediated isothermal amplification (LAMP) for DNA and RT-LAMP for RNA, have been developed [18]. The high specificity and sensitivity, rapid execution, performance under isothermal condition, time-saving, easy observation of by-products [19], and low cost make RT-LAMP unrivaled among diagnostic techniques. It is easy and simple to perform only with four appropriate primers,
Application of enzyme-linked immunosorbent assays for the diagnosis of emerging equine paramyxovirus infection
Shirai Junsuke,Matsumura Tomio
Acta Veterinaria , 2007, DOI: 10.2298/avb0703143s
Abstract: Enzyme-linked immunosorbent assays (ELISAs) for the diagnosis of infections with Nipah or Hendra viruses, developed by the Australian Animal Health Laboratory (AAHL), were evaluated for their diagnostic application in Japan. The original ELISA protocols for the two viruses differed, with the method for Nipah virus developed to detect antiviral antibody in swine sera and that for Hendra virus developed to detect the antibody in horse sera. However, preprocessing of horse sera was not necessary for the Nipah virus ELISA as there was no interfering nonspecific reactivity. Cross-reactivity between antibodies against the Nipah and Hendra viruses demonstrated a two times higher OD (450 nm) in a homologous reaction than in a heterologous reaction. While the diagnostic threshold of antibody levels in the Hendra virus ELISA was dependent on OD value, results were easily influenced by the concentration of virus antigen in the test sample. For the diagnosis of either virus infection in horses, more rigorous standards for diagnostic thresholds of antibody titers are recommended. This is a good application model for the diagnosis of these emerging diseases.
Detección de enfermedades virales afectando al pimentón en los municipios Iribarren, Jiménez y Torres del estado Lara, Venezuela, utilizando la técnica ELISA.
Rodríguez,Y.; Rangel,E; Centeno,F.; Mendoza,O; Parra,A;
Revista de la Facultad de Agronomía , 2004,
Abstract: sweet pepper is an important crop in lara state, where farmers harvest about 50% of the national production. this crop has been affected in previous years, by the increase of a complex of apparently viral symptoms, mainly dwarfing, severe mosaic, leaf curl, fern leaf, blistering and leaf deformation. in order to get current information about which viruses are present, 85 samples in iribarren, jiménez and torres counties of lara state were collected and analyzed by elisa technique with commercial kits against eight different viruses, some of them have been previously reported in the country affecting sweet pepper and other important solanaceous species. several samples were inoculated on indicator plants and their particles were observed in a transmission electron microscope. the elisa technique enabled the detection of following viruses: cucumber mosaic cucumovirus, cmv; tobacco rattle tobravirus, trv; potato y potyvirus, pvy; tobacco etch potyvirus, tev; tobacco mosaic tobamovirus, tmv; pepper mild mottle tobamovirus, pmmov; tomato ringspot nepovirus, torsv; and tobacco ringspot nepovirus, trsv. trv, torsv and trsv are detected in sweet pepper by first time in the country
Development and evaluation of an immunochromatographic strip for rapid detection of porcine hemagglutinating encephalomyelitis virus
Chen Keyan,Zhao Kui,Song Deguang,He Wenqi
Virology Journal , 2012, DOI: 10.1186/1743-422x-9-172
Abstract: Background The incidence of PHE among pigs in many countries is on the rise, and it has caused great economic losses to the pig industry. Therefore, the development of a sensitive, specific, and easily-performed assay is crucial for the rapid detection and surveillance of PHE-CoV infection and transmission. Results An immunochromatographic strip was developed for the detection of PHE-CoV. The colloidal gold-labeled MAb 4D4 was used as the detection reagent, and the MAb 1E2 and goat anti-mouse IgG coated the strip's test and control lines, respectively. The immunochromatographic strip was capable of specifically detecting PHE-CoV with a HA unit of 2 within 10 min. Storage of the strips at room temperature for 6 months or at 4°C for 12 months did not change their sensitivity or specificity. Using RT-PCR as a reference test, the relative specificity and sensitivity of the immunochromatographic strip were determined to be 100% and 97.78%, respectively. There was an excellent agreement between the results obtained by RT-PCR and the immunochromatographic strips (kappa = 0.976). Additionally, there was a strong agreement between the sandwich enzyme-linked immunosorbent assay (ELISA) and immunochromatographic strips (Kappa = 0.976). When the immunochromatographic strips were used for diagnosing PHE-CoV infection in the Jilin Province, the PHE-CoV-positive rate ranged from 61.54% in the Jilin district to 17.95% in the Songyuan district. Conclusions Based on its high specificity, sensitivity, and stability, the immunochromatographic strip would be suitable for on-site detection of PHE-CoV for surveillance and epidemiological purposes.
Detection of Maize stripe virus in different parts of sorghum plant and seed by penicillinase based direct antigen-coated enzyme-linked immunosorbent assay
YO, NARAYANA and V, MUNIYAPPA*
Indian Phytopathology , 2012,
Abstract: For the detection of Maize stripe virus (MStV) in different of parts of Sorghum bieolor plant and seed development stages, penicillinase based direct antigen-coated enzyme-linked immunosorbant assay (DAC-ELlSA) was used. The virus was detected in all parts including inflorescence, internodes, roots and basal tillers. The virus was detected in inflo
Peanut stripe potyvirus: Prevalence, detection and serological relationships
R.K. JAIN*, I. LAHIRI and A. VARMA
Indian Phytopathology , 2012,
Abstract: Peanut stripe potyvirus (PStV) has been prevalent in five major peanut [groundnut] growing states of India: Andhra Pradesh, Gujarat, Karnataka, Maharashtra and Tamil Nadu. Surveys conducted over a 3-year period (1992-94) revealed its prevalence in two more states, Rajasthan and Uttar Pradesh. Direct antigen-coated enzyme-linked immunosorbent assay (DAC-ELISA) and immunosorbent electron microscopy (ISEM) were used to detect PStV in groundnut plants collected from these states. While PStV was detected in the majority of symptomatic plants, a significant proportion (31%) of asymptomatic plants were also PStV positive. PStV could not be detected in roots and seeds from PStV-positive plants. The virus was unevenly distributed in infected plants. Composite sampling comprising of quadrifoliates of different ages from the main axis and lateral branches is thus suggested for accomplishing reliable detection. The PStV isolate used in this study was serologically related to cowpea aphid-borne mosaic (CABMV)and soybean mosaic (SbMV) potyviruses.
Injecting Heterogeneity Through Protocol Randomization
Li Zhuang,J. D. Tygar,Rachna Dhamija
International Journal of Network Security , 2007,
Abstract: In this paper, we argue that heterogeneity should be an important principle in design and use of cryptographic protocols. We use automated formal analysis tools to randomly generate security protocols as a method of introducing heterogeneity. We present the results of simulations for the case of two party authentication protocols and argue that choosing protocols randomly out of sets numbering in the hundreds of millions is practical and achievable with an acceptable overhead. To realize the simulation, we implemented a highly efficient protocol verifier, achieving approximately two orders of magnitude improvement in performance compared to previous work.
A Memory Symptom-based Virus Detection Approach
Hsien-Chou Liao,Yi-Hsiang Wang
International Journal of Network Security , 2006,
Abstract: The widespread use of the Internet has caused computer security to become an important issue. Currently, anti-virus software is the primary mechanism that prevents computers from the damage of viruses. Such a mechanism relies on the update of virus patterns (or signatures) to detect new viruses. However, serious damage is usually caused before the update occurs. In addition, a few modification of the same virus can pass the pattern matching. This is one reason that the quantity of new viruses has exceeded 600 per month. This situation has also caused inefficiency in virus scans. To overcome the above problems, a new memory symptom-based approach is proposed in this paper. This idea comes from how diseases are diagnosed in real life. Doctors diagnose diseases based on the symptoms of a patient, such as a fever, a cough, etc., rather than based on the type of virus. Similarly, the program execution requires the usage of computer resources, such as CPU, memory, network, etc. We define the usage of a resource as a ``symptom" of the program. Viruses can be detected according to their symptoms. In this paper, we focus on the memory symptom. The memory symptom of an unknown program is sampled, encoded, and matched with those of sample programs. Then a certainty factor (CF) value is computed to represent the possibility that the unknown program is a virus. In the experimental study, 109 test programs were detected. According to the analysis of the confusion matrix, a true positive rate can be as high as 97 percent, and a false positive rate can be 13 percent while the unknown rate is only 18 percent. This shows that the memory symptom-based approach is effective for virus detection.
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