• Korean Journal of Veterinary Service
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• v.42 no.4
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• pp.201-216
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• 2019

Porcine reproductive and respiratory syndrome (PRRS) is characterized by reproductive failure in sows and respiratory distress in all age pigs. Porcine respiratory disease complex (PRDC) is a disease caused by opportunistic bacterial infection secondary to a weakened immune system by a preceding respiratory infection. In this study, we tried to compare the immune responses in PRRS and PRDC groups to clearly characterize the disease severity. Eighty-five pigs were infected with various Korean field PRRS virus strains. Infected animals were classified into PRRS (n=32) and PRDC (n=53) groups based on lung lesions such as interstitial pneumonia, suppurative pneumonia, and pleuropneumonia. The immune cell population of bronchoalveolar lavage cells (BALc) was evaluated on 14 and 28 days post infection (dpi) and PMBC cytokine expression was measured on 0, 3, 7, 14 dpi to investigate early inflammatory reactions. Pulmonary lesion severity was negatively correlated with alveolar macrophage (AM) in both PRRS and PRDC groups on 14 and 28 dpi. AM in BALc was less populated in PRDC group on 28 dpi compared to PRRS group. AM in BALc was significantly less populated in PRDC group on 28 dpi compared to 14 dpi. In addition, cytotoxic T lymphocyte (CTL) in BALc was higher populated in PRDC group on 14 dpi and 28 dpi compared to PRRS group. In the case of PBMC cytokine TNF-α, IFN-α, IL-1β, IFN-γ, FoxP3, and IL-2, the PRRS group showed higher expression than the PRDC group on 7 dpi, 14 dpi, 7 dpi, 14 dpi, 14 dpi, and 14 dpi, respectively. On the other hand, in the case of IFN-β, IL-6, IL-8, IL-4, and IL-17, the PRDC group showed higher PBMC cytokine expression at 14 dpi, 7 dpi, 14 dpi, 3 dpi, and 3 dpi, respectively, than the PRRS group. Based on these results, our study could characterize differential immune responses in pigs with PRRS or PRDC.

• Korean Journal of Veterinary Research
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• v.56 no.2
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• pp.109-111
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• 2016

The present study was conducted to determine the antibiotic susceptibilities of local Mycoplasma hyopneumoniae (Mhp) and Mycoplasma hyorhinis (Mhr) filed isolates. Minimum inhibitory concentrations (MICs) of Mhp and Mhr field isolates (twelve each) obtained from enzootic pneumonia-like lung lesions during 2009-2011 from Korea were determined using the broth microdilution method. Tylvalosin showed the highest activity against Mhp and Mhr field isolates, with $MIC_{90}$ values of $0.06{\mu}g/mL$ and $0.12{\mu}g/mL$, respectively. Therefore, Korean Mhp and Mhr isolates are highly susceptible to tylvalosin.

• Korean Journal of Veterinary Research
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• v.37 no.2
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• pp.417-423
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• 1997

돼지 생식기 호흡기 증후군 바이러스의 nucleocapsid와 반응을 하는 SDOW17 단크론항체를 이용하여 중성 포르말린에 고정시킨 자연감염된 포유자돈의 폐장에서 면역조직화학법을 이용하여 돼지 생식기 호흡기 증후군 바이러스 항원을 확인하였다. 서울대학교 수의과대학 병리학교실에 의뢰된 포유자돈들 중에서 병리조직학적으로 폐장에서 간질성 폐렴이 관찰된 포유자돈 7두를 임의로 선택하여 본 실험을 실시하였다. 간질성 폐렴의 병변으로 많은 수의 대식세포 침윤을 동반한 폐포벽 두께의 증가와 제II형 폐포세포의 비후가 관찰되었다. 검사한 7두 포유자돈중에서 6두에서 돼지 생식기 호흡기 증후군 바이러스에 대한 항체를 enzyme-linked immunosorbent assay에 의해 확인하였다. SDOW17 단크론항체를 이용한 면역조직화학염색과 간질성 폐렴의 대식세포에서 돼지 생식기 호흡기 증후군 바이러스의 항원을 검출하였고, 항원은 (주로)대식세포의 세포질에서만 진한 갈색의 양성반응이 관찰되었다. 이상 검사결과 돼지 생식기 호흡기 증후군 바이러스는 폐장의 간질과 폐포강에 분포되어 있는 대식세포에서 주로 증식하는 것으로 판명되었다. 본 실험에서 사용한 면역조직화학법은 돼지 생식기 호흡기 증후군 바이러스 감염여부를 바이러스 분리 또는 혈청검사 없이 진단하는데 사용할 수 있는 유용한 진단방법으로 판명되었다.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.7
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• pp.889-897
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• 2011

Mycoplasma Pneumonia of swine (MPS) decreases the daily growth of pigs, and, co-infection with a virus sometimes causes severe pneumonia. Genetic selection of pigs resistant to the pulmonary MPS lesion might solve the economic loss due to MPS in animal production. Here, we examined the immunophenotype of Landrace line (Miyagino L2), genetically selected to reduce the incidence of pulmonary MPS lesion for 5 generations in Miyagi Prefecture Animal Industry Experiment Station. Although this line is expected to be resistant to the pulmonary MPS lesion, the biological characteristics of its immune function are not clear. We investigated details of the immunorelated phenotype of Miyagino L2 at the hematological and molecular biological level, including cytokine expression, and compared the results with that of non-genetically selected Landrace. Miyagino L2 showed decreased antigen-specific IgG and IgM production and increased CD8-positive T-cell population, and high levels of cortisol concentration, suggesting that the MPS-resistant phenotype is associated these immunological differences. Additionally, T-cell CD4 expression was highly correlated with the MPS expected breeding value. Although the detailed mechanisms underlying this high correlation remain unknown, our result suggested that the genetic selection of the expression level of CD4 might be useful to improve MPS resistance in pig production.

• Korean Journal of Veterinary Research
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• v.37 no.4
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• pp.793-807
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• 1997

We tried to develop detection system of porcine reproductive and respiratory syndrome virus(PRRSV) by in situ hybridization(ISH) in the piglets experimentally infected with KPRRS-2, the Korean isolate(12 piglets) or Mn-1b, the American isolate(4 piglets), and in the natural infection suspected 6 piglets. Twelve 30-days-old piglets(two pigs per each inoculated group) were inoculated by nasal instillation of KPRRS-2 virus(total dose $10^{4.5}TCID_{50}$), Six piglets(one pig per each group) were induced contact infection with inoculated piglets, during the experiment, and two piglets were used as control. Inoculated or contacted piglets were euthanized at 1, 3, 5, 7, 14 and 21 days postinoculation(DPI). The respiratory signs such as coughing and nasal discharge were observed on day 3 DPI, and ear cyanosis were on day 5 DPI, including contacted piglets. Through the necropsy, purple discolorization of dorsal part of lung, and hypertrophy of local lymph nodes were observed. The histopathological lesions of lung were interstitial pneumonia characterized by type 2 pneumocyte hyperplasia. We prepared the probe for ISH by RNA isolation from KPRRS-2, RT-PCR, and biotin labeling. We performed the ISH within only 1~2 hours using $Microprobe^{TM}$ capillary action system. As the results, the strong red specific positive signals, means PRRSV distribution, was mainly observed in the cytoplasm of alveolar macrophages. And also signals were detected in some type 2 pneumocytes and bronchiolar epithelium of lung, myocardium, liver, kidney, tonsil, spleen, gastrointestinal mucosa, testis and lymph nodes.

• Korean Journal of Veterinary Service
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• v.34 no.4
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• pp.313-320
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• 2011

The purpose of this study was to investigate association with gross lesions and causative pathogens of porcine respiratory disease complex (PRDC) including porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), Mycoplasma hyopneumoniae (MH), Pasteurella multocida (PM), Actinobacillus pleuropneumoniae (APP), Haemophilus parasuis (HP) in slaughtered pigs. A total of 1,200 lung samples were collected randomly from slaughtered pigs in Korea during August of 2010 through July of 2011. The gross lesions were classified according to the six stages (0, 1~10, 11~20, 21~30, 31~40 and ${\geq}41$, unit=%) and 48 samples from each stage were selected to detect viral and bacterial pathogens. The results according to the six stages were 100 (8.3%), 259 (21.6%), 326 (27.2%), 213 (17.8%), 144 (12.0%) and 158 (13.2%) cases, respectively. Prevalence of pneumonia according to season was 87.0~96.7% and the highest prevalence was in spring. In detection of pathogens by PCR, 53 samples were not detected any causative pathogens of PRDC. PCV2, PRRSV, SIV, MH, PM, APP serotype 2, APP serotype 5 and HP were positive in 45.5%, 12.5%, 10.4%, 60.1%, 1.7%, 13.9%, 12.2% and 15.6%, respectively. In co-infection, PCV2-MH was the most detected causative pathogens of PRDC. The detection rate of PCV2 and PRRSV was the highest in spring, of SIV, MH and HP was in winter. The detection rate of APP-2 and APP-5 had no seasonal prevalence. The more severe gross lesions increased, the higher the detection rate showed.

• Korean Journal of Veterinary Research
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• v.38 no.4
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• pp.751-755
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• 1998

Among 2,373 slaughtered pigs examined for one year(March 1995 to February 1996), 1,899 pigs had visible pulmonary lesions. Prevalence rate of pulmonary lesion was examined by pathological techniques according to rearing and health managements of pig farms. The results were as follows : 1. Prevalence rate of pulmonary lesion in all-in/all-out flow farms(71.9%) was lower than that in continous flow farms(85.2%). 2. Prevalence rate of pulmonary lesion in non-infected farms with Aujeszky's disease virus and/or porcine reproductive and respiratory syndrome virus(74.4%) was lower than that in infected farms(85.5%). 3. During winter, prevalence rate of pulmonary lesion in farms with cold-control facilities(83.2%) was lower than that in farms with poor cold-control facilities.

• YAKHAK HOEJI
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• v.39 no.3
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• pp.215-222
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• 1995

The in vitro antibacterial activities of new carbapenem. CRB 529, 535, 538, 545 and 550 with meropenem and imipenem were compared. CRB 529. 535, 538, 545 and 550 proved to have a broad an tibacterial spectrum. Its in vitro activity against standard 20 strains was almost the same as that of imipenem and slightly higher than that of meropenem. However. against clinical isolated P. aeruginosa, CRB 529, 535, 538, 545 and 550 showed significantly higher activity than imipenem, and also CRB 529, 535, 538, 545 and 550 showed almost the same activity than imipenem and meropenem against 82 clinical isolated strains including S. aureus (MRSA), S. aureus (MSSA), E. faecalis, E. facium, E. coli, P. aeruginosa, K. pneumonia, P. mirabiris, P. stuartii, M. morganii, C. freundii, E. cloacae, S. marcescens and A. calcoaceticus var. anitratus. The stability of CRB 529, 535, 538, 545 and 550 against porcine renal dehydropeptidase-I(DHP-1) was 10 folds higher than that of imipenem and was 3 folds higher than that of meropenem.

• Korean Journal of Veterinary Research
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• v.39 no.2
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• pp.318-326
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• 1999

Respiratory pathogenic effects of several porcine reproductive and respiratory syndrome virus(PRRSV) isolates were examined in swine tracheal ring(STR) cultures by examining their effect on ciliary activity. One high and one low pathogenic PRRSV isolates were then selected and their pathogenicity investigated in 3-week-old conventional PRRSV-seronegative pigs. Ten pigs each were inoculated intranasally with the high or low pathogenic PRRSV isolate and 6 pigs were sham inoculated as negative controls. Two pigs each from the inoculated group and one pig each from negative control group were killed on 4, 7, 14, 21 and 28 days postinoculation(pI). At necropsy, degrees of gross lung lesion was determined. Turbinate, tonsil, trachea and lung samples were collected for virus isolation or histopathology. Gross lung lesions were observed mainly on 14 days PI with high and low pathogenic isolates inducing moderate diffuse and mild gross lung lesions, respectively. Inoculation of either the high or low pathogenic virus resulted in loss of cilia in ciliated epithelium of turbinates and trachea between 7 and 28 days PI. High pathogenic virus caused increased number of Goblet cells in the tracheal epithelial layer between 4 and 21 days PI whereas the low pathogenic virus did it between 14 and 28 days PI and with a lesser degree. Although both viruses produced interstitial pneumonia, the lesion was less severe with the low pathogenic virus. The isolation of high pathogenic virus from tissues and sera was earlier and more consistent than that of the low pathogenic virus. The agreement between in vitro and in vivo tests indicates that STR cultures may be used as a routine method to determine the respiratory pathogenicity of PRRSV isolates.

• Korean Journal of Veterinary Service
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• v.34 no.4
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• pp.389-395
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• 2011

The aims of this study were to assess the lung lesions and to compare gross observations with histopathological findings in the lungs of slaughter pigs. During August of 2010 through July of 2011, the 1,200 lung samples were randomly collected from slaughtered pigs in Korea. We examined prevalence of lung lesions and classified the lung lesion according to the severity of lung lesions. For the comparison of gross lesions with histopathological findings, BALT hyperplasia was also examined. Among the tested samples, 1,100 (91.7%) had pneumonic lung lesions. In the seasonal prevalence of pneumonic lung lesions, spring was the highest followed by winter, summer and autumn, respectively. The mean pneumonic score ($mean{\pm}SD$) was $21.37{\pm}17.87$ and the highest gross lesion according to stages was 11~20% (27.2%, 326/1,200). The prevalence of pleuritis was 7.0% and the highest prevalence was determined in summer. In severity, the lungs collected in this study were frequently in chronic stage (36.4%, 437/1,200), and it was shown that BALT hyperplasia was more extensive in chronic lesion. In this study, the prevalence of pneumonic lung lesions showed a high side and appeared particularly high in the spring. Severity of lung lesion was the most prevalent chronic lesions which were consistent with histopathologic findings.