• Korean Journal of Veterinary Research
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• v.57 no.1
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• pp.37-42
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• 2017

Getah virus (GETV) infection causes sporadic outbreaks of mild febrile illness in horses and reproductive failure in pigs. In this study, we established a reverse transcription polymerase chain reaction (RT-PCR) method to detect GETV from suspected virus-infected samples. The reaction conditions were optimized and validated by using RNA extracted from GETV propagated in cell culture. A GETV-specific GED4 primer set was designed and used to amplify a 177 bp DNA fragment from a highly conserved region of the E1 glycoprotein gene in the GETV genome. RT-PCR performed with this primer set revealed high sensitivity and specificity. In the sensitivity test, the GED4 primer set detected GETV RNA at the level of $10^{2.0}\;TCID_{50}/mL$. In the specificity test, the GED4 primer set amplified only a single band of PCR product on the GETV RNA template, without non-specific amplification, and exhibited no cross-reactivity with other viral RNAs. These results suggest that this newly established RT-PCR method is useful for accurate identification of GETV infection in animals.

• Korean Journal of Veterinary Service
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• v.36 no.2
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• pp.87-93
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• 2013

This study was conducted to investigate the antimicrobial, antivirus properties of Saururus chinensis extracts. The n-hexane extracts from Saururus chinensis showed the active antimicrobial activity against gram-positive bacteria. Minimum inhibitory concentration (MIC) of Saururus chiensis n-hexane extracts was 1.25 mg/ml against B. subtilis and 2.5 mg/ml against S. aureus. The cytotoxicity effects on MDBK (Madin-Darby bovine kidney) cell were observed at the various n-hexane extract concentrations. In $TCID_{50}$ assay, 0.6 mg/ml of n-hexane extracts decreased BVD (bovine viral diarrhea) virus by 1.4 log, whereas other extracts did not show antiviral activity. In this study, The results suggested that n-hexane extracts and fractions of Saururus chinensis can be a candidate materal of feed additive to chemical antibiotics and antivirus substances.

• Journal of Microbiology
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• v.39 no.1
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• pp.67-73
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• 2001

A validation study was conducted to evaluate the efficacy and mechanism of the cryo-precipitation, monoclonal anti-FVIIIc antibody (mAb) chromatography, Q-Sepharose chromatography, and lyophilization steps involved in the manufacture of high purity factor VIII (GreenMono) from human plasma, in the removal and/or inactivation of hepatitis A virus (HAV). Samples from the relevant stages of the production process were spiked with HAV and subjected to scale-down processes mimicking the manufacture of the high purity factor VIII concentrate. Samples were collected at each step and immediately titrated using a 50% tissue culture infectious dose (TCID$\_$50/) and then the virus reduction factors were evaluated. HAV was effectively partitioned from factor VⅢ during cryo-precipitation with the log reduction factor of 3.2. The mAb chromatography was the most effective step far removal of HAV with the log reduction factor of $\geq$4.3. HAV infectivity was not detected in the fraction of factor VⅢ, while most of HAV infectivity was recovered in the fractions of flow through and wash during mAb chromatography. Q-Sepharose chromatography showed the lowest efficacy for partitioning HAV with the log reduction factor of 0.7. Lyophilization was an effective step in inactivating HAV with the log reduction factor of 2.3. The cumulative lag reduction factor, $\geq$10.5, achieved for tile entire manufacturing process was several magnitudes greater than the potential HAV load of current plasma pools.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.858-864
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• 2000

The purpose of the present study was to examine the efficacy and mechanism of the fraction IV cold ethanol fractionation and pasteurization ($60^{\circ}C$ heat treatment for 10h) steps, involved in the manufacture of albumin from human plasma, in the removal and/or inactivation of blood-born viruses. A variety of experimental model viruses for human pathogenic viruses, including the Bovine viral diarrhoea virus (BVDV), Bovine herpes virus (BHV), Murine encephalomyocarditis virus (EMCV), and Porcine parvovirus (PPV), were selected for this study. Samples from the relevant stages of the production process were spiked with the viruses, and the amount of virus in each fraction was then quantified using a 50% tissue culture infectious dose ($TCID_{50}$). The mechanism of reduction for the enveloped viruses (BHV and BVDV) during fraction IV fractionation was inactivation rather than partitioning, however, it was partitioning in the case of the non-enveloped viruses (EMCV and PPV). The log reduction factors achieved during fraction IV fractionation were ${\geq}6.9$ BHV, $\geq5.2$ for BBDV, 4.9 for EMC, and 4.0 for PPV. Pasteurization was found to be a robust and effective step in inactivating the enveloped viruses as well as EMCV. The log reduction factors achieved during pasteurization were $\geq7.0$ for BHV, $\geq6.1$ for BVDV, $\geq6.3$ for EMCV, and 1.7 for PPV. These results indicate that the production process for albumin has sufficient virus-reducing capacity to achieve a high margin for virus safety.

• Journal of Life Science
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• v.19 no.7
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• pp.928-933
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• 2009

In an effort to discover an antiviral substance against noroviruse (NV), which causes gastroenteritis illness world-wide, several plants including spices and herbs were evaluated for their antiviral activities against feline calicivirus (FCV) as a surrogate for NV. Among them, methanolic extract of green tea (Camellia sinensis L.) exhibited significant antiviral activity against FCV. After treatment with green tea extract (3.13 mg/ml) for 1 hr, FCV was completely inactivated. The antiviral activity of green tea extract against FCV was also determined to be dose and time- dependent. The results obtained in this study suggested that green tea will be effective in the prevention of food-borne diseases caused by NV.

• Korean Journal of Veterinary Research
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• v.61 no.2
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• pp.13.1-13.8
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• 2021

Mammalian reovirus (MRV) causes respiratory and intestinal disease in mammals. Although MRV isolates have been reported to circulate in several animals, there are no reports on Korean MRV isolates from wildlife. We investigated the biological and molecular characteristics of Korean MRV isolates based on the nucleotide sequence of the segment 1 gene. In total, 144 swabs from wild animals were prepared for virus isolation. Based on virus isolation with specific cytopathic effects, indirect fluorescence assays, electron microscopy, and reverse transcription-polymerase chain reaction, only one isolate was confirmed to be MRV from a Korean roe deer (Capreolus pygargus). The isolate exhibited a hemagglutination activity level of 16 units with pig erythrocytes and had a maximum viral titer of 10^5.7 50% tissue culture infectious dose (TCID₅₀)/mL in Vero cells at 5 days after inoculation. The nucleotide and amino-acid sequences of the partial segment S1 of the MReo2045 isolate were determined and compared with those of other MRV strains. The MReo2045 isolate had nucleotide sequences similar to MRV-3 and was most similar (96.1%) to the T3/Bat/Germany/342/08 strain, which was isolated in Germany in 2008. The MReo2045 isolate will be useful as an antigen for sero-epidemiological studies and developing diagnostic tools.

• Journal of Veterinary Clinics
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• v.29 no.5
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• pp.377-383
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• 2012

Bovine diarrhea is a major economical burden to the bovine industry in Korea. Since multiple infectious agents can be involved in bovine diarrhea, differential diagnosis is essential for effective treatment. Therefore, a panel of two multiplex real-time PCR assays which can simultaneously detect six major bovine enteric pathogens [i.e., bovine viral diarrhea virus (BVDV), bovine coronavirus (BCoV), group A bovine rotavirus (BRV), Salmonella spp., Escherichia coli (E. coli) $K99^+$, and Cryptosporidium parvum] was developed and applied to test 97 fecal samples collected from cattle farms in Korea. In addition, microscopic examination was also preformed on the samples to detect Coccidium oocyst. The estimated sensitivity of the multiplex PCR was 0.1 $TCID_{50}$ for BVDV, BCoV and group A BRV, 5 and 0.5 CFU for E. coli $K99^+$ and Salmonella, respectively, and 50 oocysts for Cryptosporidium. The amplification efficiency of the multiplex PCR ranged between 0.97 and 0.99 for each pathogen. Among 97 samples, 36 samples were positive for at least one of the 6 major pathogens and 6 samples were simultaneously positive for 2 pathogens by the multiplex PCR assay. Coccidium oocysts were also detected in 48 samples, which were all collected from over 1 month old calves. In conclusion, the multiplex real-time PCR panel can be a useful tool for fast and accurate diagnosis of calf diarrhea associated with BVDV, BCoV, group A BRV, E. coli $K99^+$, Salmonella, and/or Cryptosporidium and Coccidium may be an important target which needs to be included in the multiplex PCR panel in the future.

• Korean Journal of Veterinary Research
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• v.49 no.3
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• pp.201-205
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• 2009

In this study, we evaluated the stability and potency of live attenuated rinderpest vaccines of lapinized-avianized tissue culture strain origin, which had been produced annually from 2005 to 2008. When immune responses to the vaccines were evaluated using two Holstein calves weighing 100~150 kg, neutralizing antibody titer of 1 : 16 was induced at 21 days post vaccination. When calves were also inoculated with vaccines lots that had been stored for 39 months at ${4^{\circ}C}$, same level of antibody titer was observed. Using the virus titer test, we found that all batches of the vaccine that had been kept for 3, 10, 15, 22, 27, 34, 39, and 45 months showed no significant loss of titers, and fulfilled the requirement necessary ($\geq$ 3 $logTCID_50$) to be used as the national rinderpest vaccine reserve in Korea. In this study, we demonstrated that stability and potency of the rinderpest vaccines were maintained over three years when kept at ${4^{\circ}C}$ storage. This indicates that it maybe feasible to extend the expiration period of this vaccine from one year to three years.

• Korean Journal of Veterinary Research
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• v.28 no.1
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• pp.105-110
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• 1988

To establish a laboratory animal model for study on development of diagnostic methods for infectious bovine rhinotracheitis virus(IBRV), experimental infection of the virus to rabbits immunosuppressed with dexamethasone(DX) were carried out. Results obtained throughout the experiments were as follows. When lymphocyte activity was measured by lymphocyte transformation to phytohaemagglutinin in parallel with total and differential leucocyte counting, both groups treated with 2.0mg DX once and 1.0mg DX daily showed marked immunosuppression between 5 to 72 hrs. after administration. The degree of suppression of lymphocyte activities was more remarkable in the latter group. IBRV PQ7 strain at $10^{7.5}\;TCID_{50}/0.2ml$ was inoculated into conjunctival sacs of rabbits immunosuppressed with DX and non-treated. During 3 weeks observation, the immunosuppressed groups revealed mild conjunctivitis, viremia and virus recovery by 33.3 to 100%, whereas the DX nontreated group showed viremia and virus recovery with no clinical conjunctivitis by one of three rabbits(33.3%). In conclusion, it was indicated that experimental infection of IBRV PQ7 strain to rabbit was limited in prerequisite to immunologic modification by administration of immunosuppressive drugs.

• Korean Journal of Veterinary Research
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• v.30 no.1
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• pp.93-102
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• 1990

Thirty-day-old piglets were intranasally or subcutaneously inoculated with 2ml of Aujeszky's disease virus, NYJ-1 strain, at the titer of $10^{6.75}$ $TCID_{50}/0.1ml$, that was isolated from the diseased piglets in Korea, and histopathological studies were performed to elucidate the pathognomonic characters of the isolate. Results obtained through the experiments were as follows: 1. Major clinical signs on the 2nd and 3rd days post inoculation (p.i.) were fever, anorexia and dyspnea. On the 6th and 7th days p.i., nervous signs, severe dyspnea and salivation were observed in the group of intranasal inoculation, and one out of 3 piglets in this group died on the 7th day p.i.. General signs were more severe in the group of intranasal inoculation than the group of subcntaneous injection. Between the 8th and l0th days p.i., the signs subsided and the piglets were completely recovered from the illness. 2. Hematologically, most of the inoculated pigs showed a mild lymphocytopenia on the 5th and 6th days p.i.. 3. By necropsy, swelling and hemorrhagic lesions were observed in tonsil, central nervous system and lung. No specific changes were grossly found in other parenchymatous organs. 4. In histopathological study, degeneration and necrosis of nervous cells, non-suppurative meningoencephalitis, diffuse or focal gliosis, perivascular cutting and degeneration of ganglion cells were observed in central nervous system, and swelling and hemorrhagic changes were shown in the tissues of liver, lung and lymph nodes. 5. By indirect immunofluorescence antibody assay using ADV-monoclonal antibody, specific ADV antigens were detected in the tissues of tonsil, brain and spleen of the succumbed piglet. However, in the experimentally slaughtered piglets, the specific reactions were noted only in the tonsils.