• Clinical and Experimental Pediatrics
• /
• v.48 no.3
• /
• pp.260-265
• /
• 2005

Purpose : During epidemics, influenza induces a high mortality and morbidity, and when influenza is prevalent, it is revealed by increased pneumonia, hospitalization due to influenza-like illness, and mortality in community. We aimed at the isolation of influenza virus and prevalence period in Busan from 2000 to 2002. Methods : For 3 years from 2000 to 2002, we analyzed the patterns of influenza virus, the occurrence distribution of influenza by age and sex and the prevalence period after cultivating the examined materials from throat smears and snivel, collected from patients in St. Benedict Hospital Pediatrics Department, from 10 monitoring hospitals, and from 16 public health centers. Results : For three years, a total of 209 strains of influenza virus were isolated. In 2000, there were A/sydney/05/97(H3N2)-like, A/Beijing/262/95(H1N1)-like and B/Harbin/07/94-like. In 2001, there were A/Panama/2007/99(H3N2)-like and A/Newcaledonia/20/99(H1N1)-like. In 2002, there were A/Panama/2007/99(H3N2)-like, A/Newcaledonia/20/99(H1N1)-like, B/Beijing/243/97, B/Honkong/22/2001 and B/Sichuam/379/99. The occurrence distribution by sexes were 14 males and 25 females in 2000, 23 males and 33 females in 2001, 57 males and 57 females in 2002. As for the occurrence distribution by ages, 0-10 years made up 48.4 percent in 2000, 11-20 years 33.93 percent in 2001, and below 10 years was 64.91 percent in 2002. As for the occurrence distribution by month, the rate was once high in January and somewhat high in April and by June, when there happened to be various viruses, though there was a low rate in 2000. On the other hand, the virus was concentrated in February and March in 2001. And in 2002, it happened high twice, in March and November. Conclusion : Influenza virus revealed frequent antigenic changes and infect children, especially those below 10 years of age from late fall to early spring. So we should consider appropriate prevention in children.

• Journal of Aquaculture
• /
• v.21 no.4
• /
• pp.339-345
• /
• 2008

Farming of the fleshy shrimp Fenneropenaeus chinensis which is a major cultured species in the west coast of South Korea, has been suffered :trom mass mortality due to disease epizootics including viruses. Since the Pacific white shrimp Litopenaeus vannamei was introduced to Korea in 2003, farming of this species has rapidly increased for years, occupying 62.5% of total cultured shrimp production in 2007. However the studies on L. vannamei culture methods for shrimp farming situations in Korea are very limited. Nursery culture of shrimp larvae has some advantages including increased survival, improved feed efficiencies, enhanced growth performance and reduced grow-out period. In this study, L. vannamei postlarvae (${PL_3}-{PL_{10}}$) with a density of $3,750-9,090/m^3$ were cultured in four raceways under limited water exchange condition for 35 days. Survival was the highest (93.6%) in tank stocked with $4,090/m^3$ and was the lowest in tank with $9,090/m^3$ (58.1 %). Mean body weight at harvest ranged from 0.071 to 0.108 g, and FCR was 0.59-0.70 in all tanks. Concentration of total ammonia nitrogen was increased up to 20 ppm on day 10 in all tanks and thereafter gradually decreased by the third week of culture. Nitrite-nitrogen was rapidly increased from the third week, representing bio-floc condition by developed nitrifying bacterial community. Of the present nursery system some modification of structure and consideration for commercial scale are needed in order to be implemented to shrimp farmers.

• Korean Journal of Veterinary Research
• /
• v.15 no.1
• /
• pp.57-67
• /
• 1975

The poxvirus group is considered to be a typical cytoplasmic inclusion forming virus. Every poxvirus has been reported to produce only one kind of inclusion in the infected tissues. A vague concept that inclusions of poxviruses are eosinophilic or acidophilic has prevailed. Although many papers and theories about the nature of the inclusion have been presented, most of them are not quite convincing on the point of the relations with virus multiplication, and an analysis of papers published showed that there seem to be many discrepancies in the descriptions of the nature of the poxvirus inclusions. Comparative studies on host-virus interaction with cowpox, orf, swinepox and fowlpox viruses which selected from each Group (I-IV) of poxviruses were performed from the morphological and virological standpoints. At first, in cowpox virus-FL cell system, as a comparative model, cytoplasmic inclusion, nucleic acid metabolism by autoradiography and detection of viral antigen by immunofluorescence were studied and obtained the results as follows: 1. The focus-like cytopathic effect (CPE) at early stage developed to entire culture at terminal stage of infection, and also the developing status of CPE was correlated to viral doses for inoculation. Two kinds of cytoplasmic inclusions which named A and B type were easily observed by Giemsa, hematoxylin-eosin (H & E) and May-Greenwald Giemsa (MGG) stainings in the infected cells. The B type inclusions were formed at early stage of infection and the A type inclusions were produced subsequently the B type formation. The B type which common type inclusion in poxviruses was a small compact or aggregate at early stage and developed to a large diffuse body at terminal stage of infection. On the other hand, the A type inclusion which depend upon the kind of virus was appeared as round and discrete shape, and its size and number was increased gradually during the culture period. It was characteristic to form distinct halos around the both types of inclusions in acid fixed, H & E stained preparations of infected cultures. The B type inclusion was always positive in Feulgen reaction and showed as DNA containing body but the A type inclusion was not. 2. In the relationship between inclusion and DNA metabolism of infected cells by the qualitative autoradiography using 3H-thymidine, the appearance of silver grains was coincided with B type inclusion but not with A type inclusion. This showed that the DNA synthesis was proceeded in all B type inclusions except those in the terminal stage with a diffuse form. This suggested that the B type inclusions are only sites of DNA synthesis and this was proceeded after the cell infection independently. The activity of DNA synthesis of the inclusions was nearly the same as that of the nucleic of normal cells and non-inclusion bearing cells. and non-inclusion bearing cells. Regardless of the size of the degree of DNA synthesis of the B type inclusion, inclusion bearing cells all showed remarkable suppression of nuclear DNA synthesis. 3. By the direct fluorescent antibody technique viral antigen in infected cells was detected. The B type inclusions have been proved to contain a great deal of viral antigen, whereas the basic substance of A type inclusion did not show antigenicity except the round edge. It was suggested that the round edge fluorescence might be caused by the glare of cytoplasmic viral antigen which pushed out and concentrated by the A type inclusion development. 4. Hemorrhagic red pock formations on chorioallantoic membrane of embryonated chicken egg had proved the characteristic of used viral strain. 5. By the above studies on the nature of two types of inclusions and the role they play in virus multiplication, it was concluded that the B type inclusion must be the site of the synthesis of viral DNA and protein as well as the site of the virus.

• Korean Journal of Veterinary Research
• /
• v.27 no.2
• /
• pp.277-290
• /
• 1987

This paper dealt with etiological studies on the acute fatal disease of Angora rabbits occurring as a group in Korea. The disease was confirmed as an acute infectious disease caused by virus. The results obtained were summarized as follows: The disease produced a high morbidity in the rearing Angora rabbits and a high mortality in the infected rabbits, and was acute. The infected rabbits died soon without premonitory signs after inappetence. The body temperature of the affected rabbits rose to $40^{\circ}C$ and nearly all deaths occurred within 48 hours after inoculation. In many cases a bloody foam was visible from the nostrils after death. According to the progress of the disease the nervous signs, such as ataxia, paralysis of the legs, and torticollis could be recognized in the some cases. Rabbits that had recovered from the disease were severe emaciation, and bristly and sparse hairs. In macroscopical findings, there were hemorrhage and edema of the lung, hemorrhage or hyperemia of the tracheal and broncheal mucosae, appearance of blood-tinged effusion in the respiratory tract. The principal lesions were found in the liver. Usually the lobular necrosis of the liver cells was progressed, and focal necrosis and hemorrhagic spots of various sizes were often observed in the liver. Liver was as a whole pale. In chronic cases, however, there was a slight liver cirrhosis with the atrophy of the parenchymal cells. The other lesions encountered grossly consisted of swelling and petechiae of the kidney, hyperemia and hemorrhage of the spleen, catarrh of the small intestine, and hyperemia of the brain. The urinary bladder contained a lot of turbid urine or bloody urine and urinary cast, and was distended with the urine. In microscopical findings, the most striking lesions occurred in the liver and may be classified as viral hepatitis. The hepatic lesions were initially characterized by progression from periportal to peripheral necrosis of the lobules with the infiltration of mononuclear cells. Focal necrosis of various sizes, hemorrhage and hyperemia were often observed in the hepatic lobules. In chronic cases, there were intensive infiltration of lymphocytes, proliferation of fibroblasts, appearance of plasmal cells, and atrophy of parenchymal cells in the hepatic tissue. Perivascular lymphocytic infiltration and meningitis were seen in the brain and spinal cord. In the kidney, there were acute glomerulonephritis, hemorrhage, necrosis of the uriniferous tubules, and retention of eosinophilic substance within the renal tubules. Proliferation of fibroblasts and infiltration of mono-nuclear cells were found in the interstitial stroma of the kidney in chronic case. There were also hemorrhage and edema in the lung, hyperemia and hemorrhage in the trachea and bronchus, perivascular lymphocytic infiltration and focal myocardial necrosis in the heart, hyperemia and hemorrhage in the spleen, vacuolization and desquamation of mucous epithelia in the urinary bladder, catarrhal inflammation of the small intestine, hemorrhage in the adrenal cortex and hyperemia in the other organs. In the electron microscopical findings of the hepatic tissue, crystals of viral particles appeared in the cytoplasm of the hepatocytes and the sinusoidal endothelial cells, and the viral particles, were small in size and polygonal. The authors suppose the virus may belong to picornaviridae family of RNA viruses. Also immature virus-like particles, dilated rough endoplasmic reticulum and destruction of nuclear membrane were seen in the hepatocytes. From these results, it is concluded that the sudden death is an acute viral disease characterized by hepatitis and the affected rabbits may be died of viremia.

• Pediatric Infection and Vaccine
• /
• v.6 no.2
• /
• pp.219-233
• /
• 1999

Purpose : Respiratory syncytial virus(RSV) is the major cause of lower respiratory tract infection in infants and young children. This study was performed to analyze antigenic and genetic variation of G protein of subgroup A RSV. Methods : One hundred seventy-nine strains isolated at the Seoul National University Children's Hospital over 8 years-period from 1990 through 1998 were analysed for antigenic and genetic variability. Analysis was made by reactivity with monoclonal antibodies raised against RSV, and by restriction mapping and, for selected strains, nucleotide sequencing following amplification of full sequence of G gene by reverse transcription-polymerase chain reaction. Results : Restriction fragment analysis of the amplified G protein gene revealed 23 restriction patterns, 12 of which included more than 2 isolate, and the most frequent genetic type comprised 30% of the strains. Indirect immunofluorescent staining with monoclonal antibodies revealed 6 antigenic types with one predominant pattern accounting for 91% of the total strains. The most frequent antigenic type had 21 restriction patterns, and some viruses with same restiction pattern had different monoclonal antibody reaction pattern. Nucleotide sequence homology of subgroup A was 91~93% between reference(A2, Long) and Korean isolates, 93~99% among Korean isolates. Maximum-parsimony analysis demonstrated that Korean isolates were distinct from reference strains and subgroup A strains were clustered in 4 groups. Conclusion : The restriction analysis pattern of G protein gene identified greater diversity within subgroup A than was seen with the monoclonal analysis and a variety of antigenic and genetic types of RSV are circulating in Korea which are different from reference strains or strains isolated from other countries.

• Korean journal of applied entomology
• /
• v.54 no.2
• /
• pp.91-97
• /
• 2015

The sweetpotato whitefly, Bemisia tabaci, is the major insect pest that transmitted over 100 plant viruses including tomato yellow leaf curl virus (TYLCV) of tomato plant as virus vector in the world. In this study, cDNA library of whitefly was constructed using Gateway system for selecting target gene in order to control of B. tabaci using virus-induced gene silencing (VIGS) vector with RNAi. First of all, when using oligo d(T) rimer, the calculated titer of cDNA library was confirmed with $1.4{\times}10^4$ clones and average insert sizes was confirmed with 1 kb. However, insert size was very big for construction of cDNA. Otherwise, when using attB-N25 random primer and sonication for 6 sec, the calculated titer of cDNA library was confirmed with $1.04{\times}10^5$ clones. But mostly insert band wasn't identified on the electrophoresis, because it seemed that insert size is too small (${\leq}100bp$), also the size of identified insert was somewhat big. Finally, when using oligo d(T) primer and sonication for 1 sec, cDNA insert of whitefly was appropriated for VIGS with 300-600 bp. However, cDNA sequence included a poly A and titer was very low to $5.2{\times}10^2$ clones. It was supposed that heat shock transformation was used instead of electro-transformation. It is considered that when constructing cDNA library for using VIGS vector, (1) random primer should be used for First strand cDNA synthesis in order to remove poly A and (2) sonication for 1 sec should be performed in order to get appropriated insert size and (3) electro-transformation should be performed in order to improve transformation efficiency.

• Journal of Life Science
• /
• v.30 no.3
• /
• pp.313-319
• /
• 2020

Recently, cattle epidemic diseases are caused by a pathogen such as a virus or bacterium. Such diseases can spread through various pathways, such as feed intake, respiration, and contact between livestock. Diagnosis based on the ELISA (Enzyme-linked immunosorbent assay) and PCR (Polymerase chain reaction) methods has limitations because these traditional diagnostic methods are time consuming assays that require multiple steps and dedicated equipment. In this review, we propose the use of the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) Cas system based on DNA and RNA levels for early point-of-care diagnosis in cattle. In the CRISPR/Cas system, Cas effectors are classified into two classes and six subtypes. The Cas effectors included in class 2 are typically Cas9 in type II, Cas12 in type V (Cas12a and Cas12b) and Cas13 in type VI (Cas13a and Cas13b). The CRISPR/Cas system uses reporter molecules that are attached to the ssDNA strands. When the Cas enzyme cuts the ssDNA, these reporters either fluoresce or change color, indicating the presence of a specific disease marker. There are several steps in the development of a CRISPR/Cas system. The first is to select the Cas enzyme depending on DNA or RNA from pathogens (viruses or bacteria). Based on that, the next step is to integrate the optimal amplification, transducing method, and signal reporter. The CRISPR/Cas system is a powerful diagnostic tool using a gene-editing method, which is faster, better, and cheaper than traditional methods. This system could be used for early diagnosis of epidemic cattle diseases and help to control their spread.

• Tuberculosis and Respiratory Diseases
• /
• v.58 no.2
• /
• pp.167-173
• /
• 2005

Background : Airborne particles during Yellow Sand phenomena are known to be associated with the respiratory disease. The purpose of this study was to evaluate the concentration and metal component properties of Yellow Sand particles and compare with airborne microbial concentration and species in non Yellow Sand and Yellow Sand phenomena. Methods : Samplings were carried out in 2002 in Seosan, during non Yellow Sand and Yellow Sand phenomena. Samples were taken using the 8-stage Cascade impactor and metallic elements were analyzed by XRF. Those were culture on the media for bacterial and fungal culture and celline for virus. Results : The concentration of total suspended particulate matter were respectively $80.2{\mu}g/m^3$, $40.3{\mu}g/m^3$ in non Yellow Sand and Yellow Sand phenomena. The concentration of metallic elements such as Ca, Fe, Cu and Zn in Yellow Sand phenomena were higher than its in non Yellow Sand. Two bacteria, Bacillus species and Staphylococcus were grown in two periods. In both periods, several fungal spores(Mucor species, Cladosporum, Alternaria, Aspergillus, Penicillium, and Alternaria species) were identified. The differences of bacteria and fungus species not observed in Yellow Sand and non Yellow Sand. Any viruses were not isolated in between both periods. Conclusions : The concentration of total suspended particulate matter and some metallic elements in Yellow Sand phenomena were higher than its in non Yellow Sand. The difference of bacteria and fungus species was not observed in non Yellow Sand and Yellow Sand phenomena.

• Journal of Plant Biotechnology
• /
• v.44 no.4
• /
• pp.401-408
• /
• 2017

Herein, we report the meristem-tip culture from dormant buds of grape 'Kyoho' single-infected with Grapevine fleck virus (GFkV), which is phloem-limited and transmitted by graft inoculation. We produced GFkV-free shoots without thermo- or chemotherapy using meristem-tip explants approximately 0.3 mm (73 explants) and 0.8 mm long (five explants) including shoot apical meristem, 2-5 leaf primordia, and 1-4 uncommitted primordia from dormant buds of the infected woody cuttings (stored at $4^{\circ}C$). Explants were cultured on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 3.0 mg/L benzyladenine (BA) and 0.1 mg/L indole-3-butyric acid (IBA). After 16 weeks of culture, shoot (10-mm long) regeneration frequency achieved from 0.3-mm explants was 4.1% and that obtained from 0.8-mm explants was 40.0%. Virus-free efficiency (expressed as the percentage of RT-PCR negative shoots regenerated) from 0.3- and 0.8-mm explants was 100% and 50%, respectively. Following in vitro multiplication, RT-PCR assays revealed identical results to assays of the first regenerated shoots. Our new methodological approach could be applied for eliminating other viruses in grapevines, as well as for producing virus-free plants in many other deciduous tree species, including fruit trees.

• Pediatric Infection and Vaccine
• /
• v.14 no.2
• /
• pp.136-144
• /
• 2007

Purpose : Human bocavirus (HBoV) was recently identified world widely in clinical specimens from infants and children with respiratory tract illness, but the role of HBoV in respiratory tract illnesses is unknown. The aim of this study was to investigate the frequency and the clinical manifestation of HBoV in pediatric patients. Methods : We retrospectively investigated 1,777 throat swab obtained between 2005 and 2006 from pediatric in-patients with acute respiratory tract diseases at the Kwang-ju Christian Hospital. The medical records of patients with positive results were reviewed for demographic and clinical data of HBoV infections. Results : HBoV DNA was found in 84 (4.7%) of the 1,777 hospitalized children and the mean age was 19 months. The most common diagnosis were pneumonia (67.8%), bronchiolitis (35.7%). HBoV infections were found year-round, though most occurred in spring and winter months. Conclusion : HBoV is frequently found in hospitalized infants and children with acute respiratory tract diseases in Korea, but an association of HBoV with a distinct respiratory tract manifestation was not apparent. To clarify the clinical significance of HBoV, further evaluation of various age groups and clinical groups is needed.