• Pediatric Infection and Vaccine
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• v.9 no.2
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• pp.193-200
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• 2002

Purpose : This study was performed to investigate the epidemiology of viral acute lower respiratory tract infection(ALRI) in two different areas of Korea. Methods : A total of 796 patients hospitalized for ALRI aged 15 years or less from June 2000 to June 2001 in Samsung Seoul hospital(SSH) and Masan Fatima hospital(MFH) were enrolled. Viral etiologies were confirmed using nasopharyngeal aspirates. We compared etiologic agents, age distribution, clinical manifestations, and seasonal occurrence of viral ALRI between the two hospitals. Results : Virus was isolated in 208 patients(26.1%). The proportion of patients aged under 2 years in SSH was 60.2%, while those in MFH was 90.0%(P<0.05). Respiratory syncytial virus(RSV) was more prevalent in MFH, but adenovirus, influenza virus and parainfluenza virus were more prevalent in SSH(P<0.05). Croup and bronchiolitis occurred more frequently in MFH than in SSH(P<0.05). The most frequent viral pathogens causing bronchiolitis and croup were RSV and parainfluenza virus, respectively, in both hospitals. Adenovirus was the main cause of pneumonia in SSH, in contrast to RSV in MFH. In terms of tracheobronchitis, adenovirus was detected most frequently in SSH, whereas influenza virus-type A was mainly isolated in MFH. Similar pattern of seasonal occurrences of RSV, parainfluenza virus and influenza virus-type A was noted in both hospitals. Adenovirus was isolated sporadically throughout the study periods. Conclusion : Seasonal occurrence and clinical syndromes according to viral pathogens showed similar pattern in two areas. However, distribution of offending viruses was different, although this is mainly related to the different age distribution. An annual nationwide surveillance is necessary to understand the viral epidemiology associated with respiratory illnesses in Korea.

• Korean Journal of Veterinary Research
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• v.46 no.1
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• pp.21-25
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• 2006

Iridovirus is an icosahedral cytoplasmic double-stranded DNA virus with a genome size of 170-200kb. Outbreaks of fish iridovirus infection are characterized by their wide geographic distribution and broad host spectrum, especially in water temperatures of $25-27^{\circ}C$ Recently, the causative agent of high mortalities in flounder (Paralichthys olivaceus) was identified as fish iridovirus in Korea. Iridoviral infection repeatedly occurs in the same area for long periods, suggesting the possibility of viral infection in nursery. To examine this, the existence of iridovirus in juvenile flounders was detected by PCR using virus-specific primers. Antibodies induced against this virus were also examined using ELISA. As a result, juvenile fish in nursery were found to be previously infected with iridovirus, suggesting that proper prevention systems are required.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.714-720
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• 2000

Antigens of Herpes simplex virus type 1 (HSV-1) strain F were immunoblotted to identify the most immunodominant one, and the localization of this antigen was then studied using immunoelectron microscopy. The 67.8 kDa antigen appeared to be the most immunodominant one in a mouse model, and it showed randomly scattered and partially clustered distribution on the surface of the virion. The localization study was performed using immunogold with polyclonal anti-HSV-1 sera produced from BALB/c mice, and immunofluorescence demonstrated that the viral products in the HSV-2 infected Vero cells were distributed throughout the infected host cell, however, mainly on the surface of the host membrane.

• Research in Plant Disease
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• v.10 no.4
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• pp.231-240
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• 2004

In the year of 2002 annual nationwide survey of virus diseases occurring in the pepper fields and greenhouses in Korea, the distribution and the incidence of viral diseases was investigated. The pepper samples from both greenhouses (155 samples) and open fields (227 samples) were collected and further analyzed to detect eleven different viruses by RT-PCR. The results indicate that no sample collected from both greenhouse and open field seems to be infected by TMV, RMV, PVY, AMV, and TSWV. On the other hand, CMV, BBWV2, PepMoV, PMMoV, TMGMV and ToMV are readily identified from greenhouse and open field samples by RT-PCR. The infection rates of the collected samples between greenhouse and open field are largely different. Comparing with 10% of virus-infected pepper samples grown in greenhouse, approximately one third of pepper samples collected from open field are infected. The mixed-infection rates in the virus-infected greenhouse and open field samples are 16% and 61%, respectively. The dominant virus occuring in greenhouse is PMMoV, indicating that virus-infected seed stocks and infected plant debris in the growing area may be important sources of inocula. On the other hand, both CMV and BBWV2 are dominant viruses in open field. This may indicate that the migration of viruliferous insect vectors into pepper fields may be the most important source of inoculum. Also, the survey shows that BBWV2 is newly immerging virus to be controlled in Korea. The discrepancies on the distribution and the occurrence of viral diseases between field and greenhouse may provide a fact that the accumulation and distribution of inoculum by successive cultivation and the migration of viruliferous vectors into growing areas are likely to be important factors to determine the incidence of viral diseases. Therefore, the further studies on epidemiology and the consideration of new breeding program of pepper are essential to minimize virus diseases.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.1
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• pp.57-63
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• 2001

Barley Yellow Dwarf Virus (BYDV) has been a major disease causing a severe loss of yield in winter cereals worldwide. It has been recently reported that BYDV occurs frequently in wheat field and also causes serious yield reduction in Korea. This study was performed to investigate the regional distributions of BYDV strains in Korea and to identify the resistant cultivars or lines of wheat to the predominant BYDV strains, providing basic information for the breeding of BYDV-resistant wheat varieties. Using RT-PCR and EcoRI digestion methods, the regional distribution of BYDV strains in Korea from 1999 to 2000 showed that PAV strain was mainly detected about 65% (Vic-PAV 52.6% ; CN-PAV 47.4%) and MAV strain about 3%. Using ELISA test for the examination of BYDV resistance with 17 cultivars and 4 lines among Korean wheat, three cultivars, Gurumil, Topdongmil, and Olgurumil, were susceptible to BYDV and the others were resistant. In plant growth and yield component responses to BYDV infection, Gurumil showed significant difference between the uninfected and the infected, suggesting the most susceptible to BYDV among Korean wheat, but Eun-pamil and Seohae118 did no difference, an indication that they have the highest resistance.

• Korean Journal of Veterinary Research
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• v.30 no.2
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• pp.177-186
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• 1990

To investigate the etiology, pathogenicity and virological properties of NYJ-1-87 strain of Aujeszky's disease virus (ADV) that was isolated from the diseased piglet in Korea, the virus at $10^{6.0}TCID_{50}/0.1ml$ was inoculated intranasally and subcutaneously into 30 to 35 days-old piglets. Results obtained through the experiments were summarized as follows. 1. Ten of the infected piglets were clinically observed for 15 days. On the 2nd day post-inoculation(pi), the signs of pyrexia, anorexia and convulsion were noted. On the 4th to 7th days pi, nervous signs of incoordination and intermittent spasm were shown in the most of piglets, and one out of 5 piglets infected intranasally was died with severe nervous signs at the 7th day pi. The signs became relieved on the 8th day pi and all of remainder were completely recovered on the 13th to 14th days pi. 2. In hematological study, prominent decrease in the number of total leukocyte and lymphocyte was shown in the ADV-infected piglets on the 6th day pi. On the 8th day pi, the cell numbers were slightly increased and returned to normal level on the 10th day pi. 3. Viral excretion of the ADV-inoculated piglets was examined by swabbing of nasal and oral cavities, and rectal feces. During the periods of the 3rd to 11th days pi, the virus was excreted intermittently from nasal and oral cavities, and rectal feces. The nasal excretions were shown the highest virus concentration of $10^{5.2}TCID_{50}/0.1ml$ at the 5th day pi. 4. Recovery of the inoculated virus from various organs of the piglets that were died or experimentally slaughtered was attempted, and the virus was isolated from the tissues of brain and tonsil by the cultured cell-inoculation method. The highest recovery rate was noted in the tonsil. By indirect immunofluorescence antibody assay using ADV-monoclonal antibody, the viral antigens were detected in tissues of spleen and liver as well as brain and tonsil on the 7th to 9th days pi. The virus was not isolated from blood and the tissues of lung and kidney throughout the experiments. 5. Titers of virus neutralizing antibody in the piglets experimentally infected with ADV became increased after the 6th to 9th days pi in both of intranasal and subcutaneous inoculation showing the highest titers of 64 to 128 on the 29th day pi. When the antibody levels were measured by radial immunodiffusion enzyme assay, the reactive diameter was enlarged to be positive after the 4th to 6th days pi in both of intranasal and subcutaneous inoculation showing the largest diameter of 13 to 14mm on the 29th day pi.

• The Plant Pathology Journal
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• v.36 no.5
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• pp.509-514
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• 2020

Satsuma dwarf virus (SDV) seriously damages citrus production by reducing the quality and yield of fruit. To avoid contamination with SDV, mother trees are checked to be SDV-free in advance of nursery tree distribution. In this study, we compared an immunochromatographic assay (ICA) kit with double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for large-scale diagnosis of SDV in orchardgrown trees in Shizuoka Prefecture, Japan. The two methods gave conflicting results for 11 of 1,705 samples, all of which were negative by DAS-ELISA but positive by ICA. The samples scored as positive by either DAS-ELISA or ICA were analyzed by reverse transcription polymerase chain reaction and all were confirmed to be positive. These results validate the use of ICA as a screening method for large-scale diagnosis. Strain discrimination revealed that 16 of 22 isolates belonged to SDV, while citrus mosaic virus (CiMV) infection only and co-infection (SDV and CiMV) were in a minority.

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.760-764
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• 1999

A totoal of 219 pigs, 109 necropsy-pigs at the diagnostic laboratory of Cheju National University and 110 slaughter-pigs in Cheju, were evaluated for the prevalence of tissue antigen and serum antibody for spontaneus porcine reproductive and respiratory syndrome(PRRS). Tissues from 219 pigs examined for PRRS viral antigen by immmunohistochemistry included lung(cranio-ventral lobes and dorso-caudal lobes), tonsil, tracheobronchial lymph node, mesenteric lymph node, heart, kidney, liver, spleen, testis, ovary, brain, and spinal cord. Sera from 180 pigs were tested for the presence of antibody to PRRS virus by the indirect fluorescent antibody assay (IFA). In the examination of serum antibody and tissue antigen for PRRS virus, serum antibody titers were considered as positive in 10%(18/180) of animals tested and PRRS viral antigen was detected in tissues of 4%(9/219) of the pigs. PRRS virus tissue antigen was most commonly detected by immunohistochemistry in the cranio-ventral lobe and tonsil. We also confirmed the distribution of tissue antigen and prevalence of serum antibody to PRRS virus in Cheju. The detection of viral antigen by immunohistochemistry in tonsils and cranio-ventral lobes proved to be a very useful method for PRRS diagnosis.

• Biomedical Science Letters
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• v.17 no.1
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• pp.27-37
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• 2011

Hepatitis A virus (HAV) is a causative agent of triggering acute hepatitis which is transmitted by person-to-person contact and or fecal-oral route. In previous studies, most hepatitis A virus (HAV) isolates had been genotype IA in Korea. Recently, a small number of different genotypes were reported with an upsurge of acute hepatitis by HAV. Therefore, the distribution of HAV genotypes was investigated. RNA was extracted from anti-HAV IgM positive sera which were collected from February to August 2009, at a tertiary care hospital in eastern Jeonnam, Korea. Nested reverse transcription PCR and direct sequencing for VP1/P2A region of the HAV were performed. A total of 365 cases with suspected acute hepatitis were tested for anti-HAV IgM and positive results were obtained in 24 sera (9.0%), which were collected 2 to 15 days (median, 7 days) after the onset of symptoms. Of the 24 seropositive samples, 14 (58.3%) samples were positive for HAV RNA, among which 4 isolates (28.6%) were genotype IA and the other 10 (71.4%) were genotype IIIA. Both IA and IIIA genotypes were isolated from 5~6 neighboring administrative districts throughout the year without geographic or seasonal restrictions. HAV genotypes (IA and IIIA) were observed from the eastern Jeonnam for the studied.

• Korean Journal of Veterinary Research
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• v.59 no.1
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• pp.37-42
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• 2019

Worldwide, avian influenza H9N2 viruses of different lineages are the most widespread viruses in poultry. However, to date, cases in Russia have not been documented. In this study, we report the first detection of a G1-like H9N2 virus from poultry sampled at live-bird markets in Russia (Far East region) during the winter of 2018 (isolate A/chicken/Amur_Russia/17/2018). We assume there has been further circulation of the A/chicken/Amur_Russia/17/2018 H9N2 virus in the Russian Far East with possible distribution to other regions or countries in 2018-2019.