• 대한수의학회지
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• 제63권1호
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• pp.4.1-4.5
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• 2023

The prevalence of some swine reproductive and zoonotic diseases in Colombia is unknown, making their management difficult. This study assessed the prevalence of porcine circovirus type 3 (PCV3), Leptospira interrogans, pseudorabies virus, and porcine gamma-herpesvirus by polymerase chain reaction in sows in the productive stage, from farms with a history of reproductive failures, at the department of Tolima. The prevalence of PCV3 was 2.6% and 12.6% for L. interrogans, with some samples co-infected with PCV2. Owing to the coinfections with PCV2, it is necessary to establish whether the interactions between these pathogens were related to the presence of reproductive problems.

• 대한수의학회지
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• 제41권3호
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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.

• 한국동물위생학회지
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• 제34권1호
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• pp.13-18
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• 2011

The purpose of this study was to apply a nested-polymerase chain reaction (nPCR) assay to detect and differentiate PCV 2a and PCV 2b. The compared with nPCR and one-step PCR and nPCR showed more sensitive in the detection of PCV-2 from tissue and blood samples. The total of 52 tissue samples was collected from postweanning pigs from 2006 to 2010. All tissue samples showed positive for PCV-2 in one-step PCR and nPCR, followed by the nPCR in order to identify the genotypes of PCV-2. 2 samples (3.8%) showed positive for PCV 2a, and 35 samples were positive for PCV 2b (67.3%), 15 samples (28.9%) were positive the dual genotypes. In addition, 42 blood samples which were collected from the 5 different swine farms were compared figure out the detection rates of nPCR and one-step PCR. The PCV 2 was positive by one-step PCR in 21 samples (50.0%) and nPCR was positive in 37 samples (88.1%). The PCV 2 genotypes in blood samples and 32 samples (76.2%) were positive for PCV 2b and none were positive for PCV 2a, 5 samples (11.9%) were positive for dual genotypes. These results suggest that the nPCR is very efficient for genotyping blood samples and differentiating the genotypes of PCV-2 from field samples.

• Journal of Microbiology and Biotechnology
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• 제29권3호
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• pp.482-488
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• 2019

Porcine circovirus type 2 (PCV2) is the causative agent of postweaning multisystemic wasting syndrome (PMWS) in pigs. Replicase (Rep) proteins are considered essential for viral replication. Capsid (Cap) protein is the primary immunogenic protein that induces protective immunity. Little is known about comparison on the immunogenicity of PCV2 Rep and Cap fusion protein and Cap protein. In the present study, recombinant baculoviruses expressing the Rep-Cap fusion protein (Bac-Rep-Cap) and the Cap protein (Bac-Cap) of PCV2 were constructed and confirmed with western blot and indirect fluorescence assay. Immunogenicities of the two recombinant proteins were tested in mice. The titers of antibodies were determined with a PCV2-specific enzyme-linked immunosorbent assay (ELISA) and a serum neutralization assay. The $IFN-{\gamma}$ response of immunized mice was measured by ELISA. The mice immunized with the Bac-Rep-Cap and Bac-Cap successfully produced Cap-specific immunoreaction. The mice immunized with the Bac-Cap developed higher PCV2-specific neutralizing antibody titers than mice injected with the Bac-Rep-Cap. $IFN-{\gamma}$ in the Bac-Rep-Cap group was increased compared to those in the Bac-Cap group. Vaccination of mice with the Bac-Rep-Cap showed significantly decreased protective efficacy compared to the Bac-Cap. Our findings will indubitably not only lead to a better understanding of the immunogenicity of PCV2, but also improved vaccines.

• Journal of Veterinary Science
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• 제21권5호
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• pp.78.1-78.15
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• 2020

Background: Enteritis is one of the most frequently reported symptoms in piglets infected with porcine circovirus type 2 (PCV2), but the immunopathogenesis has not been reported. Objectives: This study examined the effect of a PCV2 infection on the intestinal mucosal immune function through morphological observations and immune-related molecular detection. Methods: Morphological changes within the ileum of piglets during a PCV2 infection were observed. The expression of the related-molecules was analyzed using a gene chip. The immunocyte subsets were analyzed by flow cytometry. The secretory immunoglobulin A (SIgA) content was analyzed by enzyme-linked immunosorbent assay. Results: The PCV2 infection caused ileal villus damage, intestinal epithelial cells exfoliation, and an increase in lymphocytes in the lamina propria at 21 days post-infection. Differentially expressed genes occurred in the defense response, inflammatory response, and the complement and coagulation cascade reactions. Most of them were downregulated significantly at the induction site and upregulated at the effector site. The genes associated with SIgA production were downregulated significantly at the induction site. In contrast, the expression of the Toll-like receptor-related genes was upregulated significantly at the effector site. The frequencies of dendritic cells, B cells, and CD8⁺T cells were upregulated at the 2 sites. The SIgA content decreased significantly in the ileal mucosa. Conclusions: PCV2 infections can cause damage to the ileum that is associated with changes in immune-related gene expression, immune-related cell subsets, and SIgA production. These findings elucidated the molecular changes in the ileum after a PCV2 infection from the perspective of intestinal mucosal immunity, which provides insights into a further study for PCV2-induced enteritis.

• 생명과학회지
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• 제19권10호
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• pp.1451-1455
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• 2009

Porcine cytomegalovirus (PCMV) is a betaherpesvirus which causes reproductive failure in breeding sows and generalized infection in newborn piglets. It has worldwide distribution including Korea. Serological survey on this virus has been reported in 76.3% of pigs, but virological survey and epidemiological analysis on PCMV distribution have been reported in only a few papers in Korea. In this study, we investigated the virological prevalence and infection status of PCMV on a farm level in selected swine farms with respiratory diseases. A total of 1,938 blood samples taken from groups of pigs of different ages were collected from 31 farms distributed nationwide in 2006 and 2007 and tested by PCR to detect the presence of PCMV. Virological prevalence at farm level and pig level were 96.8% and 17.5%, respectively, suggesting that PCMV has endemically infected Korean pig herds. The prevalence at farm level in gilts, sows and suckling piglet groups were 16.7%, 36.7% and 56.7%, indicating that vertical infections frequently occurred in conception or newborn stage. Thereafter, detection rates of PCMV were slightly increased in pig groups aged 40 and 70 days (70.0% and 73.3%), and then gradually decreased as they aged - 33.3% in 100, 26.7% in 130 and 16.7% in 160 day old pig groups. The prevalence at pig level has similar patterns to that at farm level. With the passage of time, the variation of infection patterns of PCMV was investigated in four PCMV-positive farms. Three blood samples were collected at intervals of 6 months in each farm, and examined for presence of PCMV using PCR. The results revealed that once PCMV was introduced to the pig farms, it continuously circulated between and within groups of sows and piglets in those farms. Taken together, it can be concluded that PCMV has endemically infected Korean pig farms and has the potential risk for emerging pathogen in combination with the known endemic pathogens including porcine reproductive, respiratory syndrome virus and porcine circovirus type 2. Therefore, more research is needed on diagnosis, epidemiology and control strategy for PCMV on the field.

• Journal of Veterinary Science
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• 제21권3호
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• pp.36.1-36.9
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• 2020

Background: Pseudorabies, also known as Aujeszky's disease, is caused by the pseudorabies virus (PRV) and has been recognized as a critical disease affecting the pig industry and a wide range of animals around the world, resulting in great economic losses each year. Shandong province, one of the most vital food animal-breeding regions in China, has a very dense pig population, within which pseudorabies infections were detected in recent years. The data, however, on PRV epidemiology and coinfection rates of PRV with other major swine diseases is sparse. Objectives: This study aimed to investigate the PRV epidemiology in Shandong and analyze the current control measures. Methods: In this study, a total number of 16,457 serum samples and 1,638 tissue samples, which were collected from 362 intensive pig farms (≥ 300 sows/farm) covered all cities in Shandong, were tested by performing enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). Results: Overall, 52.7% and 91.5% of the serum samples were positive for PRV-gE and -gB, respectively, based on ELISA results. In addition, 15.7% of the tissue samples were PCR positive for PRV. The coinfection rates of PRV with porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus, and classical swine fever virus were measured; coinfection with PCV2 was 35.0%, higher than those of the other two viruses. Macroscopic and microscopic lesions were observed in various tissues during histopathological examination. Conclusions: The results demonstrate the PRV prevalence and its coinfection rates in Shandong province and indicate that pseudorabies is endemic in pig farms in this region. This study provides epidemiological data that can be useful in the prevention and control of pseudorabies in Shandong, China.

• 대한수의학회지
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• 제51권3호
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• pp.203-208
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• 2011

Postweaning multisystemic wasting syndrome (PMWS), which was first identified in western Canada in 1991 and more recently in the United States, Europe and Asia, is an emerging disease in pigs. Porcine circovirus type 2 (PCV-2) is the primary infectious viral agent causing PMWS, but the full expression of the disease may require the presence of other agents. It is reported that there is apparent synergism between PCV-2 and porcine parvovirus (PPV) in increasing the severity of the clinical signs and lesions of PMWS. From January 2006 to May 2008, a total of the 154 lymph node samples were collected from 4~12 weeks old pigs which had been submitted to the College of Veterinary Medicine, Jeju National University, Korea. These pigs were diagnosed as PMWS on the basis of clinical and pathological examination from 48 commercial herds in Jeju Island. Based on the immunohistochemistry, porcine parvovirus was detected in 69 cases (44.8%) from 154 weaned or grower pigs. PPV antigens were detected in the cytoplasm of histiocytic cells multifocally infiltrated in the cortex and paracortex of lymph nodes. The results of this study clarify that PPV is prevalent in pigs with PMWS on Jeju Island. Therefore PPV is one of the most important co-agents in the development of naturally acquired PMWS. This study may be helpful to the control of this disease and to epidemiological aspects.

• 한국동물위생학회지
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• 제36권2호
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• pp.139-145
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• 2013

Porcine respiratory disease complex (PRDC) continues to be a significant economic problem to the swine industry. In order to elucidate the etiology of PRDC including porcine circovirus type 2 (PCV2), porcine reproductive and respiratory disease syndrome virus (PRRSV), swine influenza virus (SIV), Mycoplasma hyopneumoniae (MH), Pasteurella multocida (PM) and Actinobacillus pleuropneumoniae (APP) in Namwon, the 455 lung samples were randomly collected from slaughtered pigs, examined gross lesions indicative of respiratory disease of lung and classified the lung lesion according to the severity of lung lesions. Two hundred pigs lung tissues with pneumonic lesions were examined for pathogen by PCR. As a result, the numbers of pneumonic lesions were 357 (78.5%), mean pneumonic score ($mean{\pm}SD$) was $2.03{\pm}0.90$ and the highest gross lesion according to stages was 1 (11~20%). In detection of pathogens, PCV2, PRRSV, SIV, MH, APP and PM were positive in 76.5%, 5.0%, 6.0%, 9.0%, 4.5% and 6.0%, respectively and PCV2-MH was the most detected causative pathogens of PRDC in co-infection. In the serological test for PRRSV, PCV2, MH, APP2, APP5, HP and PM, showed high antibody positive rates 93% or more.

• 대한수의학회지
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• 제44권2호
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• pp.279-286
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• 2004

Total 160 head of porcine kidneys were examined for gross and histopathological lesions and polymerase chain reaction (PCR) for porcine circovirus type 2 (PCV-2), porcine parvovirus (PPV), Leptospira species and porcine reproductive and respiratory syndrome virus (PRRSV). Grossly, 137 kidneys (85.6%) had lesions characterized by the presence of the scattered white foci. Microscopically, multifocal interstitial nephritis, which classified into 4 grades such as, no lesion (Score 0), mild lesion (Score 1), moderate lesion (Score 2) and severe chronic lesion (Score 3) with fibrosis, was observed in 159 cases (99.4%). The histopathologic mean score for multifocal interstitial nephritis was significantly different (P<0.05) between the cases of PCV-2 single infection and the cases of co-infection with PCV-2 and PPV. According to PCR evaluation, PCV-2 were detected in 73.8% (118 cases), PPV were in 66.9% (107 cases), however Leptospira spp. and PRRSV were negative in all kidneys. Both PCV-2 and PPV were detected in 52.5% (84 cases). In 84 cases co-infected with PCV-2 and PPV, the occurrence of lymphoid follicle and vasculitis were observed as 65.5% (55 cases) and 26.2% (22 cases), respectively. These results revealed that PCV-2 and PPV were major infectious agents for interstitial nephritis in slaughtered pigs, Jeju. And the histopathologic lesions of multifocal interstitial nephritis were more severe in the case co-infected with PCV-2 and PPV.