• Korean Journal of Microbiology
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• v.43 no.4
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• pp.346-350
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• 2007

We analyzed the phenotypic changes in coagulase serotype of S. aureus isolated from clinical sources and nasal cavities of healthy persons, $1994{\sim}2005$. A total of 715 isolates, 408 methicillin resistant S. aureus (MRSA) from clinical sources and 307 methicillin-susceptible S. aureus (MSSA), were classified into eight coagulase sero-types, I to VIII. The most prevalent serotype in MRSA was type II (54.3%, 222/408) and followed IV (24.7%), III (10.9%), and V (5.2%), whereas the majorities in MSSA were type VII (30.9%, 95/307), IV (22.2%), V (22.2%) and II (7.1%). Among the isolates collected periods, significant changes of coagulase serotypes in both strains were observed. In MRSA strains, the serotype V was not detected until 1997, but rapidly increased to 18.5% (20/108) in 2005, and the serotypes III decreased from 27% (31/115) in 1994 to 0.9% (1/108) in 2005. A similar trend in MSSA strains was observed but serotype II strain was not detected in 2005. The antigenic shift and changes in the coagulase of S. aureus were confirmed.

• The Journal of the Korean Society for Microbiology
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• v.14 no.1
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• pp.17-25
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• 1979

Bacteriologic diagnosis of enteric infection remains to be an important role of clinical laboratory because of the prevalence of the infection. Often the determination of etiologic agent and its susceptibility to antibiotics are of vital importance for a proper management of the infection. In our previous paper, an analysis of the isolation of enteric pathogens for the years 1969-73 was reported to clarify the status of those years. The present analysis was made based on the data obtained during the years 1974-78, to see if any change of the status was rendered. 1. During the 5-year period, from the cultures of 7,308 stool or rectal specimens 833 patients yielded enteric pathogens: 468 Shigella, 295 Salmonella, 30 Vibrio parahaemolyticus and 40 enteropathogenic Escherichia coli(EPEC). 2. Of the 295 Salmonella, 271 were S. typhi Isolation of 12 S.paratyphi-A, 1 Salmonella group B, 4 group C, 5 group D and 2 group E meant a definite increase of these sero-groups, S. typhi was most frequently isolated in August and in December, and from 30- to 39-year-old patients. 3. Of the 468 Shigella, 10 were subgroup A, 338 subgroup B, 3 subgroup C and 117 subgroup D. Most of the subgroup B belonged to type 1,2, or 3. The proportion of S. sonnei decreased from 31.3% in 1974 to 18.2% in 1978. In foreign patients, S. sonnei remained to be the frequntly isolated species. Shigella isolation was frequent in August and in 2- to 5-year-old patients. 4. V. parahaemolyticus was isolated from 30 and EPEC from 40 patients. 5. Ninty-nine per cent and 99.5% of the S. typhi isolates were susceptible to chloramphenicol and to ampicillin respectively. 92.8% of S sonnei were susceptible to ampicillin. S. flexneri type 2 was notable for their markedely decreased proportion being susceptible to ampicillin: 84.4% in 1974 and 25.6% in 1978.

• Pediatric Infection and Vaccine
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• v.3 no.2
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• pp.145-153
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• 1996

The incidence of Adenovirus(AV) pneumonia in children is estimated at 8%. Long-term complications reported with type 7 include hyperleucent lung syndrome, bronchiolitis obliterans and may require several months to recover. We reviewed 8 case of AV pnemonia confirmed by AV culture and sero-diagnosis among selected 19 AV pneumonia suspicious cases who were admitted to the Sanggye Paik Hospital of Inje University due to clinical pneumonia from May to July 1996. From 19 children, nasal aspirates or trachial aspirates were collected: viral agents were detected by virus isolation and virus antigen was detected by indirect immunofluorescent staining. Serologic diagnosis for type-specific AV antibody was done by neutralisation test. The results are as follows: 1) Age of the patients ranged from 6 months to 47 months with a mean of $24{\pm}9$ months. 6 were male and 2 were female(M:F= 3:1). 2) Monthly distribution showed 4 cases on June, 2 cases on May and July, respectively. 3) The mean duration of admission was 20.4 days and mean duration of fever was 11.3 days 4) Peripheral leukocyte counts were elevated in 4 cases(50%) and findings of shift to left were showed in 4 cases(50%) and serum aminotransferase activities were elevated in 6 case(75%). 5) Radiologic findings include linear and streaky infiltration(1/8 cases), patchy and lobar consolidation (7/8 cases), pleural effusion(2/8 cases) and hyperleucency was seen in 3/8 cases at time of admission and increased to 6/8 cases on hospital discharge. 6) The AV serotypes were type 7, type 3, and type 1. 7) Oxygen supply was done in 4 cases(50%) and all 8 patients include 2 cases of type 7 treated with artificial ventilator were survived. In conclusion, the serotypes of AV pneumonia outbreaks in early summer of 1996 were type 7, 3, 1 and, as showed severe clinical course, continued follow up surveillance is necessary to the long term pulmonary complications.

• Journal of Life Science
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• v.19 no.9
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• pp.1304-1308
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• 2009

To investigate the infection patterns of porcine epidemic diarrhea virus (PEDV) in Korean pig farms, a total of 4,768 swine sera samples from 159 pig farms were taken twice, in June (n=82) and October (n=77) in 2007. In each farm selected for the survey, 10 samples from breeding pigs and 4 from each of the 5 age groups (30, 60, 90, 120, and 150 days) were taken, and all serum samples were tested for PEDV by the serum neutralization test. The overall seroprevalence was 62.6% (2,983/4,768), with the highest prevalence in breeding pigs (93.5%, 1,485/1,589). The prevalence showed an increasing trend with increasing age (30.8, 27.2, 44.7, 61.6, and 71.2% respectively in the 30, 60, 90, 120, and 150 days age groups) (p<0.0001 for $x^2$ trend test). The association between age and PEDV prevalence was similar in both surveys, indicating that the infection of PEDV seemed to be occurring repeatedly in the farms surveyed. This inference could also be explained by the fact that prevalence in sows was very high despite low vaccination coverage, as they are continuously exposed to PEDV in potentially infected farms for a longer period. Based on the neutralizing antibody levels in sows and growing pigs, the majority of farms (91.8%, n=146 farms) were endemically infected with PEDV, and most of pigs seemed to be intensively infected with PEDV at around early growth (41.8%) and weaning (31.5%). On the other hand, serum neutralizing antibodies were not detected in pigs older than 30 days of age in farms classified as having no PEDV infection (n=13 farms), indicating the level of maternal antibody against PEDV is decreased on a non-detectable level before the piglet is 60 days old in the field situation. The results indicated that most farms surveyed in 2007 were affected with endemic PEDV infection. Therefore, a national monitoring and control program for the endemic type PEDV infection needs further attention.

• 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.

• Korean Journal of Veterinary Research
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• v.63 no.2
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• pp.12.1-12.7
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• 2023

Bovine viral diarrhea virus (BVDV) is an RNA virus belonging to Pestivirus in the family Flaviviridae. BVDV has economic significance for the livestock industry because of its association with acute disease, fetal loss, and birth of persistently infected (PI) animals. This study aimed to investigate the BVDV infection rates in Korean native cattle farms in Jeju for further planning of a BVDV control program in the Jeju Province. BVDV antibodies and antigens were tested in 15,842 sera collected from 302 Korean native cattle herds between January 2014 and June 2017 using enzyme-linked immunosorbent assay (ELISA). Viral antigen was detected by reverse transcription-polymerase chain reaction from 60 sera that were antigen ELISA-positive. BVDV antibodies were found in 90.7% (274/302) herds and 61.1% (9,678/15,842) cows. BVDV antigens were found in 13.2% (40/302) herds and 0.4% (61/15,842) cows. The oldest animal group (> 8 years) exhibited the highest sero-positive rates (91%), while the youngest animal group (< 1 years) had the highest antigen positivity rates (0.52%). Of the 60 antigen-positive sera, BVDV types 1 and 2 were found in 36 and 12 sera, respectively. Additionally, six animals were considered to be PI as BVDV was continually detected in annual examination.

• Journal of Veterinary Clinics
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• v.32 no.4
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• pp.324-329
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• 2015

The primary aim of this study was to investigate biosecurity practices in pig farms and to determine the major risk factors associated with PCV2 infection for a sampled swine population in Korea. To this end, we analyzed data from a cross-sectional study of 296 farrow-to-finish farms, which was conducted between March and September 2014 to explore the prevalence of swine disease at farm level. Face-to-face interviews by on-site visit of trained veterinarians were conducted with the farm owners or managers using a standardized questionnaires with information about basic demographical data and management practices. Farms were classified as negative or positive through the use of infection profiles that combined data on serological testing including PCR antigen test result, antibody titer and sero-conversion pattern at each age category taking into account vaccination status. Data were analyzed using multivariate ordinal logistic regression. Results from this study indicated that biosecurity level of the farms was considered not good given low compliance of the biosecurity programs and facilities in the farm: off-site removal of dead stocks (7%), off-site location of storage facility for incoming feeds (12.6%), off-site pick-up location for finishers (19.3%), restrictions on feed supplier vehicles for farm entrance (19.6%), restriction of finisher trucks entering the farm (22.4%), and restriction on manure disposal trucks entering the farm (26.4%). In the final model (n = 255), allowance of finisher truck driver to the pig unit had increased risk of infection (OR = 2.4, 95% CI 1.22-4.67) whereas farms with a sign forbidding the entrance had decreased risk of infection (OR = 0.19, 95% CI 0.10-0.58). Further comprehensive research with larger sample size is required to better understand the multifactorial characteristic that some predisposing risk factors that were not available in this study. To the best knowledge of the authors, this was the first study to use empirical data to report risk factors associated with PCV2 infection in the Korean pig farms. Results from the current study could be used to decide optimal biosecurity measures to reduce the impact of PCV2 infection to farmers and policy makers.

• Parasites, Hosts and Diseases
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• v.58 no.3
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• pp.257-265
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• 2020

The outbreak of human toxoplasmosis can be attributed to ingestion of food contaminated with Toxoplasma gondii. Toxoplasmosis recently increased in domestic and stray dogs and cats. It prompted studies on the zoonotic infectious diseases transmitted via these animals. Sero- and antigen prevalences of T. gondii in dogs and cats were surveyed using ELISA and PCR, and B1 gene phylogeny was analyzed in this study. Toxoplasmosis antibodies were measured on sera of 403 stray cats, 947 stray dogs, 909 domestic cats, and 2,412 domestic dogs collected at nationwide regions, Korea from 2017 to 2019. In addition, whole blood, feces, and tissue samples were also collected from stray cats (1,392), stray dogs (686), domestic cats (3,040), and domestic dogs (1,974), and T. gondii-specific B1 gene PCR was performed. Antibody prevalence of stray cats, stray dogs, domestic cats, and domestic dogs were 14.1%, 5.6%, 2.3%, and 0.04%, respectively. Antigen prevalence of these animals was 0.5%, 0.2%, 0.1%, and 0.4%, respectively. Stray cats revealed the highest infection rate of toxoplasmosis, followed by stray dogs, domestic cats, and domestic dogs. B1 gene positives were 5 of stray cats, and identified to high/moderate pathogenic Type I/III group. These findings enforce that preventive hygienic measure should be strengthened at One Health level in dogs and cats, domestic and stray, to minimize human toxoplasmosis infections.