• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.585-595
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• 1992

We have investigated the characteristics of encephalomyocarditis(EMC) virus isolated in Korea. The CPE, buoyant density, polypeptide profile and the size of RNA of EMC virus were examined. The granulation, pyknosis and necrosis were observed from 30 to 48 hour's post inoculation of the virus into baby hamster kidney and lung cells. The buoyant density was 1.30 and $1.35g/m{\ell}$. Three different polypeptides, 26Kd, 32Kd, and 34Kd in size, were observed and the size of viral RNA was 7.7Kb.

• Journal of the korean veterinary medical association
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• v.28 no.12
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• pp.726-735
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• 1992

For the pathologic study of experimental encephalomyocarditis(EMC) infection in piglets by the isolates EMC $K_3$ and $K_11$ isolated from Korea,12 piglets aged 35 days divided into three groups, each of which was infected with the t

• Korean Journal of Veterinary Research
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• v.34 no.2
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• pp.349-359
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• 1994

To elucidate pathogenicity to hamster of encephalomyocarditis virus $K_3$ strain that was isolated in Korea from the swine with reproductive failures, adult male syrian hamsters were experimentally infected intraperitoneally with the virus at $10^{7.0}\;TCID_{50}/0.1ml$ and pathological and immunohistochemical studies were performed. The results obtained through the experiment were as follows. 1. Clinical signs such as depression, unkempt hair and bilateral parlysis of hind limbs were observed. 2. At necropsy, mild congestion was observed in the cerebrum, liver, kidney and lung, and atrophy was evident in testis. 3. In microscopic observation, degeneration and necrosis of the nervous cells and perivascular mononuclear cell infiltration were manifested in central nerve system, and various degrees of degeneration and necrosis of parenchymal cells were detected in pancreas, lacrimal gland, liver, kidney and testis. 4. In immunohistochemical observation, strong positive reactions were observed in degenerated parenchymal cell of testis, and weak positive reactions, in hepatocytes.

• Korean Journal of Veterinary Research
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• v.33 no.2
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• pp.301-308
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• 1993

Three or 7day old piglets were infected experimentally with different encephalomyocarditis virus isolates to detect the viral antigen by the immunoperoxidase technique and to observe strain difference in their pathogenecity in newborn pigs by comparing clinical signs and pathologic lesions. Clinical signs of the infected pigs were different depending on the virus strain, pig age and infection route. Encephalomyocarditis virus(EMCV) NVSL-PR isolate was more pathogenic than MN-25 and MN-30 isolate. Three day old piglets showed more severe illness than 7 day old piglets. Predominant clinical signs were sudden death without noticeable clinical signs and dyspnea manifested as heavy abdominal breathing. Contact-infection from infected piglets to controls was observed in the oro-nasally infected group but not the intramuscular group. Common necropsy findings of dead piglets in both age groups infected with MN-25 and NVSL-PR were accumulation of excessive fluid in the body cavities and mild to diffuse necrotic areas observed in the hearts and occasionally in the livers. Microscopically, myocarditis with inflammatory cell infiltration, necrosis of the myocardial muscle fibers and occasional mineralization were observed along with interstitial pneumonia and centrolobular necrosis in the liver. Using an immunoperoxidase technique, viral antigen was detected in myocardial muscle fibers of piglets infected with EMCV.

• Korean Journal of Veterinary Research
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• v.30 no.4
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• pp.441-446
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• 1990

Encephalomyocarditis virus infection in pigs, characterized by severe reproductive failure in sows and sudden death in less than 7 day-old-piglets, a period of several months from October to December of 1989, in Korea was occurred. The most outstanding gross lesions at necropsy were found in the heart which were consisted of pale, yellow brown necrotic foci of varying size in myocardium. In some cases, pulmonary edema and liver congestion were observed. Histopathology of the heart revealed the interstitial myocarditis, endocarditis and epicarditis with lymphocytic, plasmacytic and macrophage cell infiltration and, in some cases, calcification of the necrotic myocardial muscle fibers. In some cases of brain, the perivascular cuffing and glial nodules were observed. In the liver and the lacrimal gland varying degrees of multifocal necrosis were seen. The virus was isolated from the heart and the brain in a stillborn piglet and a mummified fetus. This outbreak represents the first case of encephalomyocarditis virus infection of pigs in Korea.

• Korean Journal of Veterinary Service
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• v.17 no.1
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• pp.67-80
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• 1994

8-10 week old ICR mice were infected intracerebrally and intraperitoneally with different encephalomyocarditis virus(K$_3$, $K_{11}$, ATT-VR 129) to observe histopathological and immunohistochemical change. Results obtained throuh the experiments were summarized as follows : 1. No differences in clinical signs by the virus strains and the inoculation routes were found. Mice infected with EMCV showed clinical signs after 3 days of inoculation. Main clinical signs were tremors, convulsions, circling movement, and uni or bilateral hindleg paralysis followed by death on the 3-8 days. In general, most of the infected animals died or recovered closely on the 8th day of postinoculation. 2. At necropsy, petechial and ecchymotic hemorrhages in lung were observed and no specific findings in other were observed. 3. In histopathological observation, neuroal cell degeneration perivascular mononucear cell in-filtration gliosis were appeared in central nervous system. Myocarditis with myocardial degeneration and necrosis, calcification were observed along with acinar cell necrosis of exocrine glands in pancreas, severe glomerulonephritis in kidney. Also, focal necrosis of hepatocytes and interstitial pneymonia hyperemia, hemorrhages in lungs were observed. 4. By immunohistochemical staining using ABCIT method, the positive cells were recognized in intracytoplasm of acinar cell in pancreas and intracytoplasm of neuronal cells in cerebrum.

• Korean Journal of Microbiology
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• v.39 no.4
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• pp.242-247
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• 2003

Murine encephalomyocarditis virus (EMCV) has been used as a surrogate for hepatitis A virus (HAV) for the validation of virus removal and/or inactivation during the manufacturing process of biopharmaceuticals. Recently international regulation for the validation of HAV safety has been reinforced because of the reported cases of HAV transmission to hemophiliac patients who had received ntihemophilic factors prepared from human plasma. The purpose of the present study was to compare the resistance of HAV and EMCV to various viral inactivation processes and then to standardize the HAV validation method. HAV was more resistant than EMCV to pasteurization (60oC heat treatment for 10 hr), low pH incubation (pH 3.9 at 25oC for 14 days), 0.1 M NaOH treatment, and lyophilization. EMCV was completely inactivated to undetectable levels within 2 hr of pasteurization, however, HAV was completely inactivated to undetectable levels after 5 hr treatment. EMCV was completely inactivated to undetectable levels within 15 min of 0.1 M NaOH treatment, however, residual infectivity of HAV still remained even after 120 min of treatment. The log reduction factors achieved during low pH incubation were 1.63 for HAV and 3.84 for EMCV. Also the log reduction factors achieved during a lyophilization process of antihemophilic factor VIII were 1.21 for HAV and 4.57 for EMCV. These results indicate that HAV rather than EMCV should be used for the virus validation study and the validation results obtained using EMCV should be precisely reviewed.

• YAKHAK HOEJI
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• v.43 no.4
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• pp.464-468
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• 1999

In order to find less toxic antiviral agents from basidiomycetes, EA, the water soluble substance, was isolated from the carpophores of Elfvingia applanata (Pers.) Karst. Anti-encephalomyocarditis (EMC) virus activity of EA was examined in Vero cells by plaque reduction assay in vitro. And the combined antiviral effects of EA with interferon (IFN) alpha and gamma were examined on the multiplication of EMC virus. EA exhibited a concentration-dependent reduction in the plaque formation of EMC virus with 50% effective concentration ($EC_{50}$) of 2.12 mg/ml. The results of combination assay were evaluated by the combination index (CI) that was analysed by the multiple drug effect analysis. The combination of EA with IFN alpha showed potent synergism with CI values of 0.40~0.60 for 50%, 70% and 90% effective levels, but that with IFN gamma showed antagonism with CI values of 2.16~2.83.

• Korean Journal of Veterinary Research
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• v.50 no.3
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• pp.221-229
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• 2010

Encephalomyocarditis virus (EMCV) belongs to the genus Cardiovirus within the family Picornaviridae. EMCV has been recognized either as a cause of mortality in young pigs, due to acute myocarditis, or of reproductive failure in sows. An EMCV K3 strain was isolated from the heart and brain in a mummified and aborted swine fetus in 1989. For the molecular characterization of the poly(C)-tract of EMCV Korean isolates, K3 strain, viral RNA was extracted and digested with RNase T1, and analyzed the length of the poly(C)-tract by polyacrylamide gel electrophoresis. The poly(C) regions also were amplified by RT-PCR and sequenced. The present study shows that K3 strain of EMCV had a short polymorphic poly(C) tracts (5 to 30 C's) with sequences consisting of $C_9$, $C_{10}$, $C_{13}$, $C_{14}$, $C_{16}$, $C_{20}$, $CUC_{11}$, $C_8UCUC_3UC_{10}$, $C_9UCUC_3UC_{10}$, $C_{10}UCUC_3UC_{10}$, etc. These polymorphism of poly(C)-tracts of EMCV K3 strain implies the historical information of in vivo and/or in vitro passage.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1570-1576
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• 2006

An encephalomyocarditis virus (EMCV-CBNU) was isolated from an aborted swine fetus in October 2005. To investigate the genetic origin and virulence of the EMCV-CBNU strain, we determined the complete sequence of the virus and tested its virulence in mice. Genetic characterization revealed that the RNA genome was composed of 7,713 nucleotides with a single open reading frame (2,292 amino acids), coding 12 proteins. The EMCV-CBNU had the shortest poly(C) tract, consisting of 10 C's ($C_{10}$), compared with all the other EMCV strains reported in GenBank. Amino acid and phylogenetic analyses showed that EMCV-CBNU had the highest genetic identity with strain 2887A (99.7%), which was originally isolated from a fetus in a pig breeding farm that had a history of reproductive failure. Because rodents are the natural host of EMCV, we investigated the virulence of EMCV-CBNU in mice. Surprisingly, all mice inoculated with more than $1{\times}10^2\;TCID_{50}/0.1ml$ of EMCV-CBNU showed symptoms of hind limb paralysis and eventually died during 3 and 8 days postinoculation (DPI). Furthermore, when we inoculated the virus into pregnant mice, all dams and their fetuses died in 6 DPI. This is the first report on a full genomic analysis of swine EMCV in Korea, which exhibits high virulence in mice.