• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.993-998
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• 2004

As Worm Virus & DDoS attack appeares, the targets and damage of infringement accidents are extending from specific system or services to paralysis of the network itself. These attacks are expending very frequently and strongly, and ISP who will be used as the path of these attacks will face serious damages. But compare to Worm Virus & DDoS attack that generally occures in many Systems at one time with it's fast propagation velocity, network dimensional opposition is slow and disable to deal with the whole appearance for it is operated manually by the network manager. Therefore, this treatise present devices how to detect Worm Virus & DDoS attack's outbreak and the attacker(attacker IP adderss) automatically.

• Journal of Microbiology
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• v.45 no.1
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• pp.48-52
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• 2007

A new procedure for the concentration of nonoviruses from water samples has been developed. This procedure (calcium flocculation-citrate dissolution method) uses the following steps: virus flocculation formed by treatment with 1 M $CaCl_2$ and 1 M $Na_2HPO_4$, virus release by sodium citrate dissolution (0.3 M Na citrate, pH 3.5), and virus re-concentration by ultrafiltration. When reverse transcription (RT)-PCR was performed after the procedure, the overall detection sensitivity for seeded noroviruses in a one liter drinking water sample was as low as 1 RT-PCR unit, which is equal to a $10^{-6}$ dilution of the virus sample. This approach showed at least a 5-fold-higher sensitivity than the current method with its three steps of adsorption-elution-concentration. The newly developed procedure was used to test different brands of bottled drinking water from China for putative contamination with noroviruses. A total of 144 samples were analyzed; all of the samples were negative for norovirus specific nucleic acids.

• Research in Plant Disease
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• v.23 no.4
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• pp.363-366
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• 2017

Barley mild mosaic virus (BaMMV), Barley yellow mosaic virus (BaYMV) and Barley yellow dwarf virus (BYDV) have been identified as an important causative agents for an economically important disease of winter barley in Korea. In this study, a multiplex reverse transcription polymerase chain reaction (mRT-PCR) method was used for the simultaneous detection. Three sets of virus-specific primers targeted to the capsid protein coding genes of BaMMV, BaYMV and BYDV were used to amplify fragments that were 594 bp, 461 bp, and 290 bp, respectively. Several sets of primers for each target virus were evaluated for their sensitivity and specificity by multiplex RT-PCR. The optimum primer concentrations and RT-PCR conditions were determined for the multiplex RT-PCR. The mRT-PCR assay was found to be a better and rapid virus diagnostic tool of specific barley diseases and potential for investigating the epidemiology of these viral diseases.

• The Plant Pathology Journal
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• v.34 no.1
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• pp.65-70
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• 2018

Co-infection with two virus species was previously reported in some cactus plants. Here, we showed that Notocactus leninghausii f. cristatus can be co-infected with six different viruses: cactus mild mottle virus (CMMoV)-Nl, cactus virus X (CVX)-Nl, pitaya virus X (PiVX)-Nl, rattail cactus necrosis-associated virus (RCNaV)-Nl, schlumbergera virus X (SchVX)-Nl, and zygocactus virus X (ZyVX)-Nl. The coat protein sequences of these viruses were compared with those of previously reported viruses. CMMoV-Nl, CVX-Nl, PiVX-Nl, RCNaV-Nl, SchVX-Nl, and ZyVX-Nl showed the greatest nucleotide sequence homology to CMMoV-Kr (99.8% identity, GenBank accession NC_011803), CVX-Jeju (77.5% identity, GenBank accession LC12841), PiVX-P37 (98.4% identity, GenBank accession NC_024458), RCNaV (99.4% identity, GenBank accession NC_016442), SchVX-K11 (95.7% identity, GenBank accession NC_011659), and ZyVX-B1 (97.9% identity, GenBank accession NC_006059), respectively. This study is the first report of co-infection with six virus species in N. leninghausii f. cristatus in South Korea.

• Korean Journal of Veterinary Service
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• v.27 no.1
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• pp.89-94
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• 2004

Total 2,451 sera collected from pig farms nationwide were tested for the detection of porcine reproductive and respiratory syndrome(PRRS) virus antibodies. The results were analyzed between different geographic regions, types of breeding pigs, and different years. The overall seroprevalence of PRRS virus antibodies for 3 years was 32.4%(705/2,451). The seroprevalence of PRRS virus antibodies in years 2000, 2001, 2002, and 2004 was 33.4% (284/850), 38.6%(291/754), 33.3%(155/466), and 17.1%(65/381), respectively. The seropevalence of PRRS virus antibody in sow in years 2000, 2001, 2002 and 2003 was 31.7%, 28.4%, 29.6%, and 13.4%, respectively. The seropevalence of PRRS virus antibody in gilts in years 2000, 2001, 2002 and 2003 was 36.6%, 67.4%, 54.7%, and 33.9%, respectively. The seropevalence of PRRS virus antibody in boars in years 2000, 2001 and 2003 was 45.7%, 36.4%, and 100%, respectively. No boar serum sample was submitted for the diagnosis of PRRS virus antibody in the year 2000. High seroprevalence of the PRRS virus antibody in sow, gilts and boars indicates that the infected breeding pigs are the major source of the PRRS virus infection, and also play an important role in spreading the PRRS virus between fan mates or herds.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.1-6
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• 2007

We describe a multiplex PCR method that can detect and differentiate simultaneously four different kinds of DNA viruses, Epstein-Barr virus (EBV), cytomegalovirus (CMV), hepatitis B virus (HBV) and parvovirus B19 (B19). Primers for the multiplex PCR reaction were designed to amplify specific regions of the EBV (pol), CMV (pol), HBV (pol) and B19 (ns) viral genomes and used to simultaneously detect individual viruses. In order to achieve optimal sensitivity and specificity for multiplex PCR, the thermo-cycling parameters, primer sequences, and concentration of each reaction components were optimized systematically. The sensitivity of the detection method ranged between 5 and 10 copies of viral genome with a mixture of multiple primer pairs. Furthermore, this highly sensitive test showed no cross-reactivity among the four viruses. Thus, the results obtained in this study provide evidence that the assay system is a good tool for supporting the diagnosis of viral infection and contamination.

• Journal of Veterinary Science
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• v.23 no.4
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• pp.51.1-51.10
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• 2022

Background: Due to the unavailability of an effective vaccine or antiviral drug against the African swine fever virus (ASFV), rapid diagnosis methods are needed to prevent highly contagious African swine fever. Objectives: The objective of this study was to establish the ladder-shape melting temperature isothermal amplification (LMTIA) assay for the detection of ASFV. Methods: LMTIA primers were designed with the p72 gene of ASFV as the target, and plasmid pUC57 was used to clone the gene. The LMTIA reaction system was optimized with the plasmid as the positive control, and the performance of the LMTIA assay was compared with that of the commercial real-time polymerase chain reaction (PCR) kit in terms of sensitivity and detection rate using 200 serum samples. Results: Our results showed that the LMTIA assay could detect the 10⁴ dilution of DNA extracted from the positive reference serum sample, which was the same as that of the commercial real-time PCR kit. The coincidence rate between the two assays was 100%. Conclusions: The LMTIA assay had high sensitivity, good detection, and simple operation. Thus, it is suitable for facilitating preliminary and cost-effective surveillance for the prevention and control of ASFV.

• Korean Journal of Veterinary Service
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• v.45 no.1
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• pp.19-30
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• 2022

In this study, a simple loop-mediated isothermal amplification (LAMP) combined with visual detection method (vLAMP) assay was developed for the rapid and specific detection of African swine fever virus (ASFV), overcoming the shortcomings of previously described LAMP assays that require additional detection steps or pose a cross-contamination risk. The assay results can be directly detected by the naked eye using hydroxynaphthol blue after incubation for 40 min at 62℃. The assay specifically amplified ASFV DNA and no other viral nucleic acids. The limit of detection of the assay was <50 DNA copies/reaction, which was ten times more sensitive than conventional polymerase chain reaction (cPCR) and comparable to real-time PCR (qPCR). For clinical evaluation, the ASFV detection rate of vLAMP was higher than cPCR and comparable to OIE-recommended qPCR, showing 100% concordance, with a κ value (95% confidence interval) of 1 (1.00~1.00). Considering the advantages of high sensitivity and specificity, no possibility for cross-contamination, and being able to be used as low-cost equipment, the developed vLAMP assay will be a valuable tool for detecting ASFV from clinical samples, even in resource-limited laboratories.

• Research in Plant Disease
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• v.27 no.3
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• pp.120-127
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• 2021

Plant viruses cause significant yield losses, continuously compromising crop production and thus representing a serious threat to global food security. Tomato spotted wilt virus (TSWV) is the most harmful plant virus that mainly infects horticultural crops and has a wide host range. Reverse-transcription quantitative real-time PCR (RT-qPCR) has been widely used for detecting TSWV with high sensitivity, but its application is limited owing to the lack of standardization. Therefore, in this study, a sensitive and accurate reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) method was established for TSWV detection. Additionally, we compared the sensitivities of RT-qPCR and RT-ddPCR for TSWV detection. Specificity analysis of RT-ddPCR for TSWV showed no amplification for main pepper viruses and negative control. TSWV transcripts levels measured by RT-ddPCR and RT-qPCR showed a high degree of linearity; however, the former yielded results that were at least 10-fold more sensitive and detected lower TSWV copy numbers than the latter. Collectively, our findings show that RT-ddPCR provides improved analytical sensitivity and specificity for TSWV detection, making it suitable for identifying low TSWV concentrations in field samples.

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.565-573
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• 1998

To study the specific tools for the diagnosis of Newcastle disease virus (NDV) in chicken, polymerase chain reaction (PCR) and its presumable conditions were evaluated for the detection of hemagglutinin-neuraminidase (HN) gene of NDV RNA. For these purposes, Kyojeongwon strain of the NDV was propagated in allantoic cavity of SPF embryonating chicken eggs, and viral RNA was extracted from fractionated virus after the allantoic fluids were ultracentrifuged with sucrose gradient. The first-strand cDNA was then made for the HN gene of NDV RNA by reverse transcription at $42^{\circ}C$ for 1 hour using specific primer complementary to the HN gene. The single-stranded cDNA was used as template in the PCR of the HN-DNA, and various conditions of the PCR were evaluated to set up method for the specific detection of the HN-DNA. The PCR conditions promising for the detection of HN gene consist of preheating at $94^{\circ}C$, 5 min, 30 cycles of denaturation at $94^{\circ}C$, 1 min, annealing at $55^{\circ}C$, 1 min and polymerization at $72^{\circ}C$, 2 min, and a cycle of extension at $72^{\circ}C$, 5 min. when NDVs of allantoic fluids without fractionation were applied to the above PCR condition, the HN genes were detected effectively not only from Kyojeongwon but from other velogenic strains such as Herts and a field isolate.