• 대한미생물학회지
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• 제35권2호
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• pp.129-139
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• 2000

Acinetobacter baumannii strains are emerging pathogens of the nosocomial infection with an increasing frequency in recent years. The therapeutic difficulty due to the wide spread of multiple resistant strains was major problem in A. baumannii infection. It seems likely that high frequency of A. baumannii infection will be increasing epidemiological importance in the future. However, the current limited understanding of the epidemiology of A. baumannii infections is caused by lack of a rapid and practical method for the molecular characterization of A. baumannii strains. This study was undertaken to determine molecular types and genetic similarity among A. baumannii strains isolated from four hospitals by RAPD analysis. Eighty-five strains, including 40 from Chunnam University Hospital, 27 from Dankook University Hospital, 15 from Yonsei University Hospital, and 3 from Seonam University Hospital, were classified into three molecular types. Molecular type II was the most common pattern and included 72 strains. All strains from Dankook University Hospital and 40 strains from Chunnam University Hospital belonged to molecular type I or II. A. baumannii strains form Yonsei University Hospital were very distant similarity values. The range of genetic similarity values among 85 strains of A. baumannii was 0.26 to 1.00. Although phenotypes including biotype and antimicrobial resistance pattern of A. baumannii strains were same or very similar to each other, their RAPD patterns were quite different. Typing with phenotypes was found to be less reliable than molecular typing by RAPD analysis. These results suggest that RAPD analysis provides rapid and simple typing method of A. baumannii strains for epidemiological studies. This work is the first epidemiological report of A. baumannii infections in Korea and it is hoped that results of this work may contribute to a better understanding of the clinical importance and epidemiology of A. baumannii strains.

• 한국임상수의학회지
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• 제32권1호
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• pp.78-84
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• 2015

Although researches have highlighted the important role of enhanced farm biosecurity to reduce the severity and prevalence of diseases in livestock, to date there has been little study in Korea on farmers' adoption of biosecurity measures to control porcine reproductive and respiratory syndrome virus (PRRSV) infection. To mitigate the risk of PRRSV infection in pigs, the risk factors by which PRRSV is introduced in pig farms must be determined. The primary aim of this study was to investigate pig producers' perceptions about on-farm biosecurity practices. We also analyzed data obtained from a cross-sectional study on 196 farrow-to-finish farms conducted between March 2013 and February 2014 to identify risk factors for PRRSV infection at farm level. Standardized questionnaires with information about basic demographical data and management practices were collected in each farm by on-site visit of trained veterinarians. Farms were classified as negative or positive through the use of infection profiles that combined data on PCR positive pigs and serological testing including antibody titer, sero-conversion pattern at each age category, and vaccination status. Data on biosecurity practices, farm management and environmental characteristics were analyzed using multivariate ordinal logistic regression. Generally, the biosecurity level in the pig farms included in this study were insufficient to reduce/prevent the risk of PRRSV infection given the high pig density areas and the considerable extent of vehicle movement. Factors associated with PRRSV infection were those where owners used on-farm vaccination programs had a lower risk of infection (OR = 0.19, 95% CI 0.06-0.61). The results from the analysis may guide to tailor biosecurity measures in the reduction or prevention of PRRS to the specific circumstances of pig farms in different localities of the world. To the best knowledge of the authors, this is the first study to report information on the biosecurity practices currently implemented on Korean pig farms.

• 한국발생생물학회지:발생과생식
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• 제21권4호
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• pp.371-378
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• 2017

Interferon-stimulated gene 15 (ISG15) is known to interfere with viral replication and infection by limiting the viral infection of cells. Interferon-stimulated gene 15 (ISG15) interferes with viral replication and infectivity by limiting viral infection in cells. It also plays an important role in the immune response. In this study, tissue-specific expression of ISG15 in healthy rock bream samples and spatial and temporal expression analysis of rock bream ISG15 (RbISG15) were performed following rock bream iridovirus (RSIV) infection. RbISG15 expression was significantly higher in the eye, gill, intestine, kidney, liver, muscle, spleen, and stomach, but low in the brain. There were particularly high levels of expression in the liver and muscle. RbISG15 expression was also examined in several tissues and at various times following RSIV infection. ISG15 expression increased within 3 h in the whole body and decreased at 24 h after infection. In addition, temporal expression of several tissues following RSIV infection showed a similar pattern in the muscle, kidney, and spleen, increasing at 3 h and decreasing at 72 h. These results suggest that ISG15 plays an important role in the immune response of rock bream. Overall, this study characterizes the response of RbISG15 following RSIV infection.

• Journal of Preventive Medicine and Public Health
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• 제56권3호
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• pp.212-220
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• 2023

Objectives: This study compared the epidemiological and clinical manifestations of patients hospitalized with respiratory syncytial virus (RSV) infection before and during the coronavirus disease 2019 (COVID-19) pandemic at a tertiary care hospital in Chiang Mai Province, Thailand. Methods: This retrospective observational study utilized data from all cases of laboratory-confirmed RSV infection at Maharaj Nakorn Chiang Mai Hospital from January 2016 to December 2021. Differences in the clinical presentation of RSV infection before (2016 to 2019) and during (2020 to 2021) the COVID-19 pandemic were analyzed and compared. Results: In total, 358 patients hospitalized with RSV infections were reported from January 2016 to December 2021. During the COVID-19 pandemic, only 74 cases of hospitalized RSV infection were reported. Compared to pre-pandemic levels, the clinical presentations of RSV infection showed statistically significant decreases in fever on admission (p=0.004), productive cough (p=0.004), sputum (p=0.003), nausea (p=0.03), cyanosis (p=0.004), pallor (p<0.001), diarrhea (p<0.001), and chest pain (p<0.001). Furthermore, vigilant measures to prevent the spread of COVID-19, including lockdowns, also interrupted the RSV season in Thailand from 2020 to 2021. Conclusions: The incidence of RSV infection was affected by the COVID-19 pandemic in Chiang Mai Province, Thailand, which also changed the clinical presentation and seasonal pattern of RSV infection in children.

• 미생물학회지
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• 제46권2호
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• pp.134-139
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• 2010

전 세계 인구의 1/3을 감염시키고 있는 결핵균은 21세기에도 인류를 위협하는 병원균이다. 결핵균에 대항하는 Th1 면역 반응은 결핵균의 세포 내 성장을 제어하는 것으로 알려져 있으나, 이는 결핵균 감염을 자연 치유하는 수준에는 미치지 못한다. 본 연구에서는 C57BL/6 마우스에 병원성 결핵균인 H37Rv를 감염시켰을 때 숙주의 면역 반응에 대항하여 결핵균이 자신의 유전자 발현을 변화시킨다는 사실을 규명하기 위하여, 결핵균 유전자 중 16S rRNA, acr, fbpA, aceA, ahpC 등의 발현을 real-time RT-PCR을 이용하여 연구하였다. 16S rRNA의 copy number는 감염 후 30일까지 급격하게 증가하였는데 이는 CFU 측정 결과와 일치하고 있다. 결핵균 유전자 중 주된 항원으로 작용하는 유전자인 fbpA의 copy number를 CFU로 나눈 값으로 표현한 발현 양상은 감염 후 10일까지 증가하다가 감소되었다. Heat shock protein인 ${\alpha}$-crystallin을 coding하는 acr은 감염 후 지속적으로 높아졌으나, 산화적 스트레스 환경에서 발현되는 효소들인 ahpC와 aceA의 발현은 감염 후 20일 동안 높아졌다가 30일에는 약간 감소하였으나 비교적 높은 수준을 유지하였다. 이상의 결과는 결핵균이 숙주의 면역 반응이 개시되면 결핵균의 주된 항원 중 하나인 Ag85A를 코딩하는 유전자인 fbpA의 발현 수준을 낮춰 숙주의 Th1 먼역 반응이 낮아지도록 유도한다는 증거로 볼 수 있으며, 면역 반응이 활발해 짐에 따라 큰포식세포 내에서 산화적 스트레스로부터 균을 보호하기 위하여 ahpC와 aceA의 발현이 높아진 것으로 해석된다. 따라서 본 연구는 결핵균이 유전자 발현을 숙주의 면역 반응에 대항하여 스스로 변화시켜 적대적인 숙주 세포 내에서 살아 남을 수 있는 생존 전략을 구사한다는 가능성을 제시한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.699-702
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• 1998

This study investigates the population model of the spread of HIV/AIDS which the infection is generated by an infectious in dividual in a population of susceptibles. A mathematical model is presented for the transmission dynamics of HIV infection within the communities of homosexual males. The pattern on the epidemic character of HIV, the causative agent of AIDS, was analysed by the mathematical model of AIDS system which is derived according to the ecological relationship between five epidemilogic states of individuals. The computer simulation was performed using real data.

• 대한수의학회지
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• 제45권1호
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• pp.55-61
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• 2005

Serum samples of 1,175 pigs from 148 Korean swine farms not using Mycoplasma hyopneumoniae (M. hyo) vaccines were collected for seroepidemiological study of M. hyo infection by indirect ELISA method. Informations of each farm were provided about province where the farm was located and season when blood samples were collected. Then, the selected farms were divided into farm units which had 5 serum samples according to production stages : sow, suckling piglet (<30 days old), nursery pig (30-70 days old), and growing pig (>70 days old). Seroprevalence of M. hyo infection according to production stages, province, and season was investigated by using ELISA-positve rate of the selected samples for each study. This study showed that 85.34% (78.94-91.78%, 95% CI) of farms were positive to M. hyo infection and 34.81% (32.09-37.53%, 95% CI) among pigs were sero-positive to M. hyo infection in Korean swine farms. In the study of seroprevalence by production stage, most farms had sows and growing pigs which were sero-positive to M. hyo infection (sow: 83.05%, growing pigs: 87.72%) and most pigs seemed to be naturally infected by M. hyo at 8-10 weeks of age. Also, M. hyo infection showed seasonal pattern that most pigs were infected in late fall to early winter. However, in the study of seroprevalence by province, there was no significant correlation between province and M. hyo sero-positive rate.

• 한국동물위생학회지
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• 제22권4호
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• pp.371-375
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• 1999

Total 1,434 sera collected from 72 pig farms were tested for the detection of porcine reproductive and respiratory syndrome (PRRS) virus antibodies. The overall seroprevalence of PRRS virus antibodies was 49.3% (707/727). Of 72 farms tested 59 (81.9%) farms had at least one or more than one pigs with PRRS virus antibodies. The seroprevalence of PRRS virus antibody varied with age. Seroprevalence of PRRS virus antibody in 1 to 30-day-old, 31 to 40-day-old, 41 to 50-day-old, 51 to 60-day-old, and over 61-day-old pig were 27.4%, 52.3%, 57.9%, 52.7%, and 68.2%, respectively. Gilt showed relatively higher seroprevalence (61.2%) than sow (29.2%) and boar (38.3%). In most farms, the infection of PRRS virus was chronic and confined to grower or finisher. This pattern of infection suggests that partial depopulation of the infected herds appears be one of the measures to eradicate the PRRS virus infection. High seroprevalence of the PRRS virus antibody in gilts and boars indicates that the infected gilts and boars in the breeding farms are the major source of the PRRS virus infection, and also play an important role in spreading the PRRS virus between fan mates or herds.

• 대한수의학회지
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• 제40권1호
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• pp.138-144
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• 2000

This study was carried out to investigate the pathogenicity of Korea N caninum isolates, KBA-1 and KBA-2 on SCID mouse following 3 different routes of infection. NC-1 was served as reference isolate. The pathogenecity was evaluated by progression of clinical signs, histopathology and immunohistochemistry. Pathogenicity of KBA-2 appears to be stronger than that of KBA-1 but weaker than that of NC-1. Progress of clinical signs and lesion distribution and pattern of each isolates were similar when the isolates were infected either subcatareously or intraperitoneally. However, oral inoculation of tachyzoites failed to induce the infection.

• Preventive Nutrition and Food Science
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• 제10권2호
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• pp.161-166
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• 2005

We investigated the effect of pycnogenol (PYC) supplementation on retarding the immune dysfunction of CS7BL/6 mice after murine AIDS (MAIDS) development. Dysfunction of T and B cell mitogenesis from primary cultured splenocytes has been observed with retrovirus infection and PYC supplementation partially recovered the dysfunction of T and B cells. There was an abnormal shift of cytokine pattern with retrovirns infection, which was designated by the decreased secretion of Th1 cytokines and increased secretion of Th2 cytokines. PYC supplementation increased IL-2 and $IFN-\gamma$ secretion and decreased IL-4, IL-6, and $TNF-\alpha$ secretion, but it was not sufficient enough to maintain the normal level of these cytokines. Hepatic vitamin E level was significantly decreased by retrovirns infection, in accordance with increased hepatic lipid peroxidation level, whereas PYC supplementation normalized the hepatic level of vitamin E and lipid peroxidation. This study suggests that PYC supplementation may partially help retard the incidence of symptoms during MAIDS.