• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.760-764
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• 1999

A totoal of 219 pigs, 109 necropsy-pigs at the diagnostic laboratory of Cheju National University and 110 slaughter-pigs in Cheju, were evaluated for the prevalence of tissue antigen and serum antibody for spontaneus porcine reproductive and respiratory syndrome(PRRS). Tissues from 219 pigs examined for PRRS viral antigen by immmunohistochemistry included lung(cranio-ventral lobes and dorso-caudal lobes), tonsil, tracheobronchial lymph node, mesenteric lymph node, heart, kidney, liver, spleen, testis, ovary, brain, and spinal cord. Sera from 180 pigs were tested for the presence of antibody to PRRS virus by the indirect fluorescent antibody assay (IFA). In the examination of serum antibody and tissue antigen for PRRS virus, serum antibody titers were considered as positive in 10%(18/180) of animals tested and PRRS viral antigen was detected in tissues of 4%(9/219) of the pigs. PRRS virus tissue antigen was most commonly detected by immunohistochemistry in the cranio-ventral lobe and tonsil. We also confirmed the distribution of tissue antigen and prevalence of serum antibody to PRRS virus in Cheju. The detection of viral antigen by immunohistochemistry in tonsils and cranio-ventral lobes proved to be a very useful method for PRRS diagnosis.

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.367-371
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• 2001

Multiplex PCR and immunohistochemistry were used to detect and differentiate between porcine circovirus (PCV) type-I and the PCV associated with postweaning multisystemic wasting syndrome (PMWS). Unique DNA product to PCV type-II was confirmed the some organs including lymph nodes, tonsil and spleen from eight pigs in Jeju by multiplex PCR. In this study, the samples were tested by a multiplex PCR assay to determine the type of PCV in each case; all cases were PCV type-II positive. PCV type-II was identified not only in typical PMWS cases, but also in field cases submitted with various clinical histories, some of which were not suggestive of PMWS. Immunohistochemically PCV type-II antigen was detected in macrophage-like cells in the tonsil, liver, lymph nodes and spleen, while some hepatocytes and renal tubular epithelial cells were also positive to the virus. This study suggested that PCV type-II is one of the causative agents of PMWS as well as the major type of PCV in the affected pigs in Jeju.

• 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.14 no.2
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• pp.143-147
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• 1991

Between June and August 1990, the tonsils of 86 healthy pigs were examined for the presence of staphylococci. All of the pigs examined harboured Staphylococci in the tonsils, the most predominant Staphylococcus species was Staphylococcus aureus(45.3%) followed by Staph hyicus subsp chromogenes (20.9%), Staph hyicus subsp hyicus (16.3%), Staph hominis(4.7%), Staph simulans(2.3%) and Staph xylosus(1.2%), Unidentifiable species were isolated from 3(3.5%) of the 86 tonsils examined. Thirty-nine strains of Staph aureus were subjected to the biotyping scheme of Hajek & Marsalek all the strains were classified as biotype B.

• Korean Journal of Veterinary Research
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• v.47 no.2
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• pp.175-185
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• 2007

This study was carried out to investigate the pathogenesis and pathogenicity of the porcine circovirus type 2 (PCV2) Korean isolate from weaned pigs. Twenty four weaned pigs, PCV2, porcine reproductive and respiratory syndrome virus (PRRSV) and porcine parvovirus (PPV) antibodies free, were allocated to 4 groups (n = 6). Six pigs were inoculated intranasally with PCV2 alone, 6 with PCV2 and PRRSV, 6 with the combined PCV2/PRRSV/PPV inoculum, and 6 were remained as a uninoculated negative control. Pigs were killed 3 and 6 weeks after inoculation and tissue samples examined for gross and microscopic lesions and for the presence of PCV2 antigens and nucleic acids. Experimentally inoculated pigs were evaluated for 3 considerations: 1. development of postweaning multisystemic wasting syndrome (PMWS), 2. distribution of viral antigens by immunohistochemistry and polymerase chain reaction (PCR), and 3. cytokine mRNA levels in lymph nodes. Pigs inoculated with PCV2/PRRSV/PPV showed typical clinical signs, gross findings, and histopathologic characteristics of PMWS. In the PCV2/PRRSV/PPV inoculated group, the PCV2 antigen was widely distributed in various parenchymal organs such as brain, spinal cord, tonsil, lymph nodes, lung, heart, liver, kidney, spleen, and peyer's patch. Lymph node mRNA expression of IL-$1{\alpha}$, IL-2R and IL-8 was determined by real-time PCR. The pigs of PCV2/PRRSV and PCV2/PRRSV/PPV inoculation group, the mRNA expression was characterized by a decrease of IL-$1{\alpha}$, IL-2R and IL-8. The decrease of cytokine mRNA represent the state of T cell immuno-suppression in pig, and nicely support the evidence for the impairment of immune system in pigs with PMWS. In conclusion, PCV2 infection and some additional infectious causes such as PRRSV and/or PPV are warranted for the presence of PMWS in weaned pigs in Korea.

• 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.