• The Plant Pathology Journal
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• v.33 no.5
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• pp.467-477
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• 2017

A nationwide survey was performed to investigate the current incidence of viral diseases in Korean sweet potatoes for germplasm and growing fields from 2011 to 2014. A total of 83.8% of the germplasm in Korea was infected with viruses in 2011. Commercial cultivars that were used to supply growing fields were infected at a rate of 62.1% in 2012. Among surveyed viruses, the incidence of five Potyvirus species that infect sweet potato decreased between 2012 and 2013, and then increased again in 2014. Representatively, the incidence of Sweet potato feathery mottle virus (SPFMV) was 87.0% in 2012, 20.7% in 2013 and then increased to 35.3% in 2014. Unlike RNA viruses, DNA viruses were shown to decrease continuously. The incidence of Sweet potato leaf curl virus (SPLCV) was 5.5% in 2003, 59.5% in 2011, and 47.4% in 2012. It then decreased continuously year by year to 33.2% in 2013, and then 25.6% in 2014. While the infection rate of each virus species showed a tendency to decline, the virus infection status was more variable in 2013 and 2014. Nevertheless, the high rate of single infections and mixed infection combinations were more variable than the survey results from 2012. As shown in the results from 2013, the most prevalent virus infection was a single infection at 27.6%, with the highest rate of infection belonging to sweet potato symptomless virus-1 (SPSMV-1) (12.9%). Compared to 2013, infection combinations were more varied in 2014, with a total of 122 kinds of mixed infection.

• Pediatric Infection and Vaccine
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• v.23 no.2
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• pp.87-93
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• 2016

Purpose: An outbreak of influenza virus is uncommon in neonatal intensive care unit (NICU). The clinical presentation of influenza virus infection in neonates is diverse. This study was aimed to report an outbreak of influenza A in a NICU and to investigate the clinical characteristics of influenza virus infection in neonates especially preterm infants during the 2011-2012 influenza season in Korea. Methods: We reviewed the medical records of 29 patients who were evaluated by respiratory virus multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) at NICU of Kosin University Gospel Hospital during the 2011-2012 seasonal influenza outbreak in Korea. Results: Eleven patients (37.9%) were influenza A virus RT-PCR positive during the survey periods. They were all preterm infants and three of them had no symptoms. Eight patients had symptoms and it was fever (18%, 2/11), respiratory difficulty (72.7%, 8/11) without symptoms of upper respiratory infection, and gastrointestinal symptoms (27.3%, 3/11). The median duration of symptom was 5 days. There were differences of duration of admission at the test of respiratory RT-PCR, Clinical Risk Index for Babies (CRIB) score, use of mechanical ventilation, and use of dexamethasone before infection between influenza A virus RT-PCR positive and negative group. All 11 patients with influenza A were discharged without any complications. Conclusions: The symptoms of influenza A virus infection in the preterm infants is nonspecific. Influenza A virus should be considered as a possible cause of infection in NICU during the influenza season in the community.

• Proceedings of the Microbiological Society of Korea Conference
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• 2000.05a
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• pp.23-36
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• 2000

Japanese encephalitis virus (JEV) is the causative agent of a mosquito-borne encephalitis and is transmitted to human via persistently infected mosquito vectors. Although the virus is known to cause only acute infection, there were reports that showed neurological sequelae, latent infection in peripheral mononuclear cells, and recurrence of the disease after acute encephalitis. Innate resistance of certain cell lines, abnormal SN1 expression of the virus, and anti-apoptotic effect of cullular bcl-2 have been suggested as probable causes of JEV persistence even in the absence of defective interfering (DI) particles. Although possible involvement of DI particles in JEV persistence was suggested, neither has a direct evidence for DI presence nor its molecular characterization been made. Two questions asked in this study are whether the DI virus plays any role in JEV persistent infection if it is associated with and what type of change(s) can be made in persistently infected cells to avoid apoptosis even with the continuous virus replication, DI-free standard stock of JEV was infected in BHK-21, Vero, and SW13 cells and serial high multiplicity passages were performed in order to generate DI particles. There different-sized DI RNA species which were defective in both structural and nonstructural protein coding genes. Rescued ORFs of the DI genome maintained in-frame and the presence of replicative intermediate or replicative form RNA of the DI particles confirmed their replication competence. On the other hand, several clones with JEV persistent infection were established from the cells survived acute infections during the passages. Timing of the DI virus generation during the passages seemed coincide to the appearance of persistently infected cells. The DI RNAs were identified in most of persistently infected cells and were observed throughout the cell maintenance. One of the cloned cell line maintained the viral persistence without DI RNA coreplication. The cells with viral persistence released the reduced but continuous infectious JEV particle for up to 9 months and were refractory to homologous virus superinfection but not to heterologous challenges. Unlike the cells with acute infection these cells were devoid of characteristic DNA fragmentation and JEV-induced apoptosis with or without homologous superinfection. Therefore, the DI RNA generated during JEV undiluted serial passage on mammalian cells was shown to be biologically active and it seemed to be responsible, at least in part, for the establishment and maintenance of the JEV persistence in mammalian cells. Viral persistence without DI RNA coreplication, as in one of the cell clones, supports that JEV persistent infection could be maintained with or without the presence of DI particles. In addition, the fact that the cells with JEV persistence were resistant against homologous virus superinfection, but not against heterologous one, suggests that different viruses have their own and independent pathway for cytopathogenesis even if viral cytopathic effect could be converged to an apoptosis after all.

• Annals of Clinical Neurophysiology
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• v.21 no.1
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• pp.48-52
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• 2019

Primary Epstein-Barr virus (EBV) infection can manifest with a broad spectrum of neurological complications. There are only rare reports of Guillain-$Barr{\acute{e}}$ syndrome (GBS) supervening on meningitis in patients with primary EBV infection. Clear evidence of central nervous system infection makes it difficult for the clinicians to consider a diagnosis of GBS. We present a patient with GBS supervening on meningitis in primary EBV infection.

• Korean Journal of Clinical Laboratory Science
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• v.42 no.1
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• pp.1-15
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• 2010

Swine influenza virus (SIV) or swine-origin influenza virus (S-OIV) is endemic in swine, and classified into influenza A and influenza C but not influenza B. Swine influenza A includes H1N1, H1N2, H3N1, H3N2 and H2N3 subtypes. Infection of SIV occurs in only swine and that of S-OIV is rare in human. What human can be infected with S-OIV is called as zoonotic swine flu. Pandemic 2009 swine influenza H1N1 virus (2009 H1N1) was emerged in Mexico, America and Canada and spread worldwide. The triple-reassortant H1N1 resulting from antigenic drift was contained with HA, NA and PB1 of human or swine influenza virus, PB2 and PA polymerase of avian influenza virus, and M, NP and NS of swine influenza virus, The 2009 H1N1 enables to transmit to human and swine. The symptoms and signs in human infected with 2009 H1N1 virus are fever, cough and sore throat, pneumonia as well as diarrhea and vomiting. Co-infection with other viruses and bacteria such as Streptococcus pneumoniae can occur high mortality in high-risk population. 2009 H1N1 virus was easily differentiated from seasonal flu by real time RT-PCR which contributed rapid and confirmed diagnosis. The 2009 H1N1 virus was treated with NA inhibitors such as oseltamivir (Tamiflu) and zanamivir (Relenza) but not with adamantanes such as amantadine and rimantadine. Evolution of influenza virus has continued in various hosts. Development of a more effective vaccine against influenza prototypes is needed to protect new influenza infection such as H5 and H7 subtypes to infect to multi-organ and cause high pathogenicity.

• Korean Journal of Poultry Science
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• v.35 no.3
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• pp.225-240
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• 2008

Marek's disease virus(MDV) is a highly cell-associated, lymphotropic $\alpha$-herpesvirus that causes paralysis and neoplastic disease in chickens. The disease has been controlled by vaccination which was provided the first evidence for a malignant cancer being controlled by an antiviral vaccine. Marek's disease pathogenesis is complex, involving cytolytic and latent infection of lymphoid cells and oncogenic transformation of $CD4^+$ T cells in susceptible chickens. MDV targets a number of different cell types during its life cycle. Lymphocytes play an essential role, although within them virus production is restricted and only virion are produced. Innate and adaptive immune responses develop in response to infection, but infection of lymphocytes results in immunosuppressive effects. Hence in MDV-infected birds, MDV makes its host more vulnerable to tumour development as well as to other pathogens. All chickens are susceptible to MDV infection, and vaccination is essential to protect the susceptible host from developing clinical disease. Nevertheless, MDV infects and replicates in vaccinated chickens, with the challenge virus being shed from the feather-follicle epithelium. The outcome of infection with MDV depends on a complex interplay of factors involving the MDV pathotype and the host genotype. Host factors that influence the course of MD are predominantly the responses of the innate and adaptive immune systems, and these are modulated by: age at infection and maturity of the immune system; vaccination status; the sex of the host; and various physiological factors.

• The Plant Pathology Journal
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• v.25 no.4
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• pp.328-332
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• 2009

Diseases caused by Pepper yellow leaf curl virus infection is considered to be emerging plant diseases in Indonesia in the last five years. One key factor for disease management is the availability of accurate detection of the virus in plants. Polyclonal antibody for Pepper yellow leaf curl Indonesia virus-Bogor (PYLCIV-Bgr) was produced for detection of the virus using I-ELISA and DIBA methods. The antibody was able to detect PYLCIV-Bgr from infected plants up to dilution 1/16,384 and cross reaction was not observed with Cucumber mosaic virus (CMV), Tobacco mosaic virus (TMV), and Chilli veinal mottle virus (ChiVMV). Positive reaction was readily detected in membrane containing Begomovirus samples from Yogyakarta (Kaliurang and Kulonprogo) and West Java (Bogor and Segunung). Infection of PYLCIV-Bgr in chillipepper, tomato, and Ageratum conyzoides was also confirmed using polyclonal antibody for PYLCIV-Bgr in DIBA. Polyclonal antibody for PYLCIV-Bgr is suggested to be included in disease management approach due to its good detection level.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.507-512
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• 1998

Molecular analysis has been done for characterization of the interactions between three beet curly top virus (BCTV) strains and two Arabidopsis ecotypes in terms of virus inducible disease symptoms and infectivities. The total DNA was isolated from three tissues (shoot tips, infection origins and roots) of virus infected plants and this DNA was analyzed by quantitatively and qualitatively to elucidate virus movement and symptom development. CTV-Worland infected Col-O and Sei-O showed only symptom shown in hypersusceptible ecotype Sei-O by BCTV-worland was shoot tip stunting. Kinetics of virus DNA accumulation of three different viruses indicated that roots contained more virus DNA than shoot tips or infection origins, and that disease symptom severity was strongly correlated with virus DNA accumulation. These results suggest that the mild and Worland-specific symptoms shown in Sei-O by BCTV-worland are caused by the interactions of host factors provided by hypersusceptible ecotype and viral factors of mild strain.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.882-889
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• 2002

Hantaan vims production, using human immortalized retina cell (PER. C6), was investigated to develop an inactivated virus vaccine. To infect Hantaan virus into PER. C6, two infection methods (medium-to-cell and cell-to-cell) were tried, and IFA results showed that the cell-to-cell infection method was very useful for producing Hantaan virus-infected PER, C6. Hantaan virus production was significantly affected by the growth rate of PER. C6 and the content of FBS in medium. Higher specific growth rate of infected PER. C6 and lower FBS content induced higher production of Hantaan virus. The inactivated human cell-culture vaccines with various EIA titers were prepared, their antibody responses were compared with those of inactivated suckling mouse brain vaccines ($Hantavax^처리불가$). and the result showed their immunogenicities were slightly higher than those of inactivated suckling mouse vaccines. Therefore, this study shows the possibility of the development of Hantaan virus vaccine from a human cell culture.

• Korean journal of applied entomology
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• v.14 no.2 s.23
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• pp.71-76
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• 1975

The study has been carried to find a proper site for seed potato production in Jeon Bug Province, Korea. Two fields, one at the alpine area (700-800 m sea level) in Muju county and the other at the plain area in Jeoniu, were chose for this study. Seed potatoes for the experiment were obtained from Alpine Experiment Station and from the traditional sources in Muju area. During the growing season the virus infection (Potato virus X,S,Y, and M) was detected by serolgical method. The average percent of virus infection on the original seed potatoes, which have been used as a seed source in Korea, was $50.5\%$, and the ratio of the infection for each of potato virus, Y, M and X was 34..87, 40.33, 41.00 and $87.10\%$, respectively. Infection percentage of virus at first year in Muju area was $11.7\%$ and those in Jeonju area was $18.95\%$. In case of potato virus Y, the most prevalent virus in Korea, lower Infection percentage $(6.45\%)$ was found in Muju area than in tile Jeonju area $(26.0\%)$ when the seed from Alpine Experiment Station was planted in both areas. The percentage of infected seed potato, Alpine Experiment Station$(41.75\%)$ was almost the same as those from the traditional sources in Muju $(42.17\%)$. The production of seed potato, however, was much better by the seeds from Alpine Experiment Station.