• Korean Journal of Veterinary Service
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• v.43 no.4
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• pp.267-271
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• 2020

The emergence of highly contagious viral diseases of livestock and poultry such as foot-and-mouth disease (FMD), African swine fever (ASF) and highly pathogenic influenza (HPAI) have necessitated the formulation of policies and regulatory frameworks for preventing ingress of exotic diseases and controlling dissemination of endemic diseases within the country. The disease control ratings to manage contagious livestock disease in farms have not being widely used because the evaluation parameters were not being considered inappropriate. The purpose of this study was to reinforce the validity of the parameters for evaluation factors and the objectivity of the scoring criteria in the application of the current disease management rating system. The diseases subject to intensive management were improved by reflecting farm situation. For the evaluation based on the disease grading system of farms, the diseases subject to intensive management were realized, the list of diseases for evaluating the vaccination rate was revised, and the quarantine and sanitation management standards were revised. The effectiveness of the improved livestock disease management system was confirmed through the application of actual pig farms. Therefore, this system will be used as a means to evaluation the biosecurity at the farm units. Through this, it will contribute to establish effective biosecurity measures for each farm by improving and supplementing the present disease grading system.

• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.93-102
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• 2017

A duplex RT-PCR (dRT-PCR) assay was developed for the simultaneous detection and discrimination of non-virulent and virulent Newcastle disease virus (NDV) in a single PCR tube. Primers targeting the large polymerase protein (L) gene and the fusion protein (F) gene of NDV were designed to detect all NDVs (by common type PCR primers) and virulent NDVs (by pathotype PCR primers), respectively and evaluated experimentally with reference NDV strains and other poultry viral pathogens. PCR products of the expected size of 386 bp were amplified from all NDV samples whereas PCR products of the expected size of 229 bp were amplified from virulent NDV samples alone. Cross reaction was not observed with other avian viral pathogens. The detection limit of NDV by the dRT-PCR was estimated to be $10^3$ 50% egg infectious dose/0.1 mL. In the dRT-PCR using field isolates of NDV, the pathotype PCR primers detected specifically all of virulent field isolates of NDV from Malaysia, Pakistan and China whereas common type PCR primers detected 94.4% (51/54) of field isolates of NDV from China. Three Chinese NDV isolates with false negative result were non-virulent viruses. Our results indicate that the dRT-PCR might provide a rapid and simple tool for rapid simultaneous detection and discrimination of non-virulent and virulent NDVs. Therefore the developed dRT-PCR assay provides a powerful novel means for the rapid diagnosis of Newcastle disease.

• Korean Journal of Poultry Science
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• v.37 no.2
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• pp.167-172
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• 2010

An immunochromatograhy (IC) based infectious bursal disease virus (IBDV) detection kit, which employed two anti-IBDV VP2 monoclonal antibodies, was evaluated for rapid diagnosis of infectious bursal disease virus (IBD). The detection limit of the IC kit for IBDV was $10^{3.1}$ to $10^{3.9}$ $EID_{50}$/mL, indicating that the IC kit detected IBDV sensitively as same as double antigen capture ELISA but less than a RT-PCR assay. The IC kit did not detect other viral pathogens such as Newcastle disease virus, infectious bronchitis, avian influenza virus, and infectious larynotracheitis virus. When applied to tissue samples of experimental chickens died 3 or 4 days post infection after very virulent IBDV (strain Kr/D62) infection, the IC kit detected IBDV in all samples of the bursa of Fabricius, spleen, kidney, cecal tonsil and in 87.5%, 37.5% and 0% of liver, thymus and proventriculus samples. In particular, BF tissue samples showed stronger signal bands than other tissues. Positive signal was observed. All except for one thymus sample of samples having negative results by the IC kit showed the same result with DAS-ELISA but RT-PCR assay detected IBDV in some of IC kit negative samples of thymus and proventriculus. When swab samples from the bursa of Fabricius of dead chickens (n=231) on field farms were tested, the sensitivity and specificity of the IC assay relative to RT-PCR was 100% (109/109) and 97.5% (119/122), respectively and kappa value between both assay was 0.97. The kit can provide a useful aid for rapid detection of IBDV in chickens under field circumstances.

• Korean Journal of Veterinary Research
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• v.48 no.1
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• pp.89-92
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• 2008

The pirarucu, Arapaima gigas (body weight = 18.3 kg and total length = 102 cm) which had been reared in one of the private commercial aquaria for exhibition was found dead and submitted for diagnostic examination. A pure bacterial culture was isolated from the kidney, which was enlarged, and contained fluids. Result of the bacterial identification yielded Serratia fonticola. This paper describes the first isolation of S. fonticola from pirarucu.

• Korean Journal of Veterinary Service
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• v.39 no.2
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• pp.107-116
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• 2016

In the study, we developed and evaluated a uracil N-glycosylase (UNG)-supplemented single-tube nested reverse transcription-polymerase chain reaction (UsnRT-PCR) assay that can carried out first-round RT-PCR and second-round nested PCR in a reaction tube without reaction tube opening and can simultaneously detect EU- and NA-PRRSV. The UsnRT-PCR confirmed to have a preventing ability of mis-amplification by contamination of pre-amplified PRRSV DNA from previous UsnRT-PCR. Primer specificities were evaluated with RNAs extracted from 8 viral strains and our results revealed that the primers had a high specificity for both genotypes of PRRSV. The sensitivity of the UsnRT-PCR was 0.1 $TCID_{50}$/0.1 mL for EU- or NA-PRRSV, respectively, which is comparable to that of previously reported real time RT-PCR (RRT-PCR). Clinical evaluation on 110 field samples (60 sera and 50 lung tissues) by the UsnRT-PCR and the RRT-PCR showed that detection rates of the UsnRT-PCR was 70% (77/110), and was relatively higher than that of the RRT-PCR (69.1%, 76/110). The percent positive or negative agreement of the UsnRT-PCR compared to RRT-PCR was 96.1% (73/76) or 90.9% (30/33), showing that the test results of both assays may be different for some clinical samples. Therefore, it is recommend that diagnostic laboratory workers use the two diagnostic assays for the correct diagnosis for the relevant samples in the swine disease diagnostic laboratories. In conclusion, the UsnRT-PCR assay can be applied for the rapid, and reliable diagnosis of PRRSV without concerns about preamplified DNA carryover contamination that can occurred in PCR process in the swine disease diagnostic laboratories.

• Korean Journal of Veterinary Research
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• v.38 no.4
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• pp.843-852
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• 1998

From Jan. 1996 to Oct. 1997, 29 pigs with 40-70 days old showing dyspnea inappetite and polyserositis were collected and carried out necropsy, bacterial culture, histopathology, avidin biotin complex(ABC) stain, fluorescent antibody(FA) test, and electron microscopy. In the study, 4 strains from 3 pigs were isolated from meninges, pleura and synovial fluid and also were identified as Haemophilus parasuis serovar 5. Main histopathological lesions of 29 pigs with polyserositis were frequently composed of fibrinous peritonitis(27), pleurisy(22), interstitial pneumonia(21), fibrinous epicarditis(20), fibrinopurulent meningitis(8) and synovitis(4). By ABC stain, 11/29(37.9%) pigs with polyserositis were confirmed to have H parasuis serovar 5 in the cytoplasm of macrophages and neutrophils in cerebral meninges, epicardium, pleura surface of lung or serosa of spleen. ABC stain(20.8~40.0%) to detect H parasuis serovar 5 in tissues was more sensitive than bacterial culture(10.3%), but less sensitive than FA test(62.5%) using frozen tissues even though the result of 8 cases. By electron microscopy, a bacterium was also detected in the cytoplasm of macrophages in purulent exudate of cerebral meninges. Consequently, we confirmed that H parasuis serovar 5 has been involving to cause pigs with polyserositis and can be detected by FA and ABC stain as reliable diagnostic tools.

• Korean Journal of Veterinary Research
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• v.42 no.4
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• pp.485-493
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• 2002

The purpose of this study was to develope a computer program to help with gross diagnosis of protein-energy balance and feeding management practice and with the prediction about the risk possibility of productive disease such as reproductive and metabolic disorders by evaluating fat, protein, and milk urea nitrogen (MUN) from individual cow milk in dairy herd Somatic cell counts also represent the condition of udder health. The principal flow charts of this program was to check on herd management, sampling the composite milk, analysis the milk composition, conversion of data from milking equipment to program, input and analysis of data in program, and report. This program is compatible with window 95/98 system. The major analytical elements of this program were presented as; the profile of herd lactation curve analysis of the test-day milk production level, the distribution of somatic cell count, the fat to protein ratio to evaluate body energy balance, and the interpretation of dietary protein-energy balance by milk protein and MUN contents for individual cows. This program using milk fat, protein, MUN, and somatic cell counts will serve as a monitoring tool for the protein-energy balance and the feeding management practice, and for distribution of mastitis in individual cows. It will also be used to manage the nutritional and reproductive disorders and mastitis at the farm level.

• Korean Journal of Veterinary Research
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• v.42 no.2
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• pp.163-170
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• 2002

The relationship between level of milk composition and conditions of ovary and uterus were analyzed in Holstein cows at seven farms participating in a reproductive herd health management program. Milk data were taken from 503 early lactating cows between 30 and 60 days in milk with reproductive examination with ultrasonography from september 1999 to August 2000. Milk fat, protein and solid-not-fat concentration in the herds were $3.70{\pm}1.08%$, $2.97{\pm}0.35$, and $8.41{\pm}0.61%$, respectively. The reproductive disorder relative to normal cows had higher risk in the cows that the level of protein was lower than 2.70%. Also, the higher milk fat than 4.50% were associated with a higher risks in the uterine disease and follicular cysts. Therefore, the cows with the fat to protein ratio of > 1.30 had higher risks for reproductive disorder such as cystic ovarian diseases, inactive ovaries and endometritis. These results indicated that cows diagnosed with reproductive disorder were energy deficient prior to reproductive disorder diagnosis. Consequently, milk fat and protein analyses may be used serve as a monitoring tool for condition of ovary and uterus in early lactating cows

• Research in Plant Disease
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• v.29 no.3
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• pp.286-294
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• 2023

Biological and molecular characterization of a Korean isolate of Orthotospovirus chrysanthinecrocaulis (formerly known as chrysanthemum stem necrosis virus, CSNV) isolated from Chrysanthemum morifolium was determined using host range and sequence analysis in this study. Twenty-three species of indicator plants inoculated mechanically CSNV-Kr was investigated for determination of host range. CSNV-Kr induced various local and systemic symptoms in the inoculated plant species. CSNV-Kr could not infect three plant species and induced symptomless in systemic leaves in Nicotiana tabacum cultivars, though the plant samples reacted positively with the antiserum to CSNV by double-antibody sandwich-enzyme-linked immunosorbent assay. The complete genome sequence of CSNV-Kr was determined. The L RNA of CSNV-Kr consists of 8,959 nucleotides (nt) and encodes a putative RNA-dependent RNA polymerase. The M RNA of CSNV-Kr consists of 4,835 nt and encodes the movement protein (NSm) and the glycoprotein precursor (Gn/Gc protein). The S RNA of CNSV-Kr consists of 2,836 nt and encodes NSs protein and N protein. The Gn/Gc and N sequence of CSNV-Kr were compared with those of previously published CSNV isolates originating from different countries at nucleotide and amino acid levels. The Gn/GC sequence of CSNV-Kr shared 98.8-99.5% identity with CSNV isolated from other countries and the N sequence of CSNV-Kr shared 98.8-99.6% identity. No particular region of variability could be found in either grouping of viruses. All of the CSNV isolates did not show any relationship according to geographical origins and isolation hosts, suggesting no distinct segregation of the CSNV isolates.

• Research in Plant Disease
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• v.29 no.1
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• pp.94-99
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• 2023

Blueberry red ringspot virus (BRRSV) and blueberry scorch virus (BlScV) are included in the quarantine virus list managed by the Korean Animal and Plant Quarantine Agency. A multiplex polymerase chain reaction (PCR) assay with an internal control was developed for the simultaneous detection of both viruses. The specific primers used here were designed based on the highly conserved regions of the genomic sequences of each virus, obtained from the National Center for Biotechnology Information nucleotide databases. The primers were designed to amplify a partial sequence within coat protein (CP) for detecting BRRSV and a partial sequence within the CP-16 kDa for detecting BlScV. 18S ribosomal RNA (rRNA) was used as internal control, and the primer set used in a previous study was modified in this study for detecting 18S rRNA. Each conventional PCR using the BRRSV, BlScV, and 18S rRNA primers exhibited a sensitivity of approximately 1 fg plasmid DNA. The multiplex PCR assay using the BRRSV, BlScV, and 18S rRNA primers was effective in simultaneously detecting the two viruses and 18S rRNA with a sensitivity of 1 fg plasmid DNA, similar to that of conventional PCR assays. The multiplex PCR assay developed in this study was performed using 14 blueberry cultivars grown in South Korea. BRRSV and BlScV were not detected, but 18S rRNA was all detected in all the plants tested. Therefore, our optimized multiplex PCR assay could simultaneously detect the two viruses and 18S rRNA in field samples collected from South Korea in a time-efficient manner. This approach could be valuable in crop protection and plant quarantine management.