• Journal of Animal Science and Technology
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• v.65 no.4
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• pp.698-719
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• 2023

Postweaning multisystemic wasting syndrome (PMWS) is caused by a systemic inflammation after porcine circovirus type 2 (PCV2) infection. It was one of the most economically important pathogens affecting pig production worldwide before PCV2 vaccine was first introduced in 2006. After the development of a vaccine against PCV2a type, pig farms gradually restored enormous economic losses from PMWS. However, vaccine against PCV2a type could not be fully effective against several different PCV2 genotypes (PCV2b - PCV2h). In addition, PCV2a vaccine itself could generate antigenic drift of PCV2 capsid. Therefore, PCV2 infection still threats pig industry worldwide. PCV2 infection was initially found in local tissues including reproductive, respiratory, and digestive tracks. However, PCV2 infection often leads to a systemic inflammation which can cause severe immunosuppression by depleting peripheral lymphocytes in secondary lymphoid tissues. Subsequently, a secondary infection with other microorganisms can cause PMWS. Eleven putative open reading frames (ORFs) have been predicted to encode PCV2 genome. Among them, gene products of six ORFs from ORF1 to ORF6 have been identified and characterized to estimate its functional role during PCV2 infection. Acquiring knowledge about the specific interaction between each PCV2 ORF protein and host protein might be a key to develop preventive or therapeutic tools to control PCV2 infection. In this article, we reviewed current understanding of how each ORF of PCV2 manipulates host cell signaling related to immune suppression caused by PCV2.

• Korean Journal of Veterinary Service
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• v.29 no.3
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• pp.249-256
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• 2006

Porcine circovius type 2 (PCV 2) is a novel virus of Circoviridae familiy which is considering the cause of postweaning multisystemic wasting syndrome (PMWS). This study was carried out to investigate the prevalence of PCV 2 infection of swine in eastern areas of Gangwon province from February to June in 2005. Polymerase chain reaction (PCR) were conducted to identify the PCV 2 genome against 80 pigs. The number of infection and its rate of 4 areas, 8 farms and 80 pigs were 3 (75.0%), 7 (88.0%) and 44 (55.0%), respectively.

• Korean Journal of Veterinary Service
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• v.31 no.3
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• pp.347-356
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• 2008

The purpose of this study was to evaluate the efficacy and cross-protection of serovar 12 against serovar 4 or 5 of H parasuis with M+$Parapac^{(R)}$. A total of 141 piglets from 2(A and B) farms were used and divided into experimental group and control group in each farm. Farm A has been detected H parasuis serovar 12, whereas farm B has been detected H parasuis serovar 4 or 5 from post-weaned pigs with PMWS. The piglets were vaccinated intramuscularly with 2.0ml of M+$Parapac^{(R)}$ in experimental group or normal saline in control group at 1 week of age. A same booster dose was given at 3 weeks of age. In order to value the antibody titer to H parasuis using by tube agglutination test, blood samples were collected from piglets at the aged of 1 week, 6 and 14 weeks. In experimental group and control group, the average antibody titers were $32.5{\pm}21.0,\;114.5{\pm}34.0,\;98.1{\pm}55.4$ and $32.9{\pm}18.6,\;25.8{\pm}36.9,\; 746.7{\pm}1,215.8$ at the aged of 1 week, 6 and 14 weeks, respectively. The cumulative clinical sign indexes by standard guideline of Schering-Plough Animal Health Corp were 486 and 1,069, respectively. The average daily gains and feed conversion rates were $0.553{\pm}0.016kg$ and $0.492{\pm}0.004kg$, and 1.99 and 2.24, respectively. The average gross lesion scores were $1.0{\pm}0.8$ and $1.9{\pm}0.6$, respectively. According to these results, the M+$Parapac^{(R)}$ containing H parasuis serovar 12 may be induce circulating antibodies that cross-react with serovar 4 or 5 and have a protection of PMWS with H parasuis.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.49-49
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• 2003

PMWS is characterised by weight loss and dyspnea combined with pathological findings of interstitial pneumonia and generalized enlarged lymph nodes. Typical histological lesions include multifocal granulomatous pneumonia, and lymphocyte depletion and multinucleated giant cell formation in lymph nodes[1,2]. (omitted)

• Feed Journal
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• v.4 no.9 s.37
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• pp.140-144
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• 2006

요즘 이상 기온이나 변화무쌍한 기후 조건으로 말미암아 사계절이 무색할 정도의 일교차나 온도차가 심해지고 여러 가지 난해한 돼지 질병들이 늘어나다보니 기본적으로 발생하는 호흡기 질병에는 의외로 무관심해지는 경향이 있는 것 같다. 다시 말해 막연한 소모성질환 운운 하다보니 오히려 쉽게 포기하려거나 관심 밖의 일로 치부한채 속수무책인 농장들이 많아진 것 같다. 항시 새로운 것만 추구하려거나 한꺼번에 해결하려하지 말고 기존의 문제점이나 쉬운 것부터 한가지씩 해결해 나가는, 그야말고 '가지치기'식으로 접근하길 바란다. 같은 내용이라도 반복된 교육이 필요하고, 알면서도 실행이 잘 안되는 타성 또한 극복해야 할 것이다. 또한 호흡기 질병이 발생하거나 PMWS 증상이 있을 때 그 구간에서만 해결하려 하지말고, 농장내 전박적인 문제점을 다시 한번 짚어보아야 한다.

• Korean Journal of Veterinary Research
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• v.43 no.3
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• pp.463-469
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• 2003

Eight nursery to grower pigs exhibiting weight loss and sudden death were diagnosed as postweaning multisystemic wasting syndrome (PMWS) based on the results of gross findings, histopathology, immunohistochemistry, fluorescent antibody test, virus isolation, PCR, serology, and electron microscopy. Groosly, the pigs had a rough hair coats and were severely emaciated. And moot lymph nodes were pale and enlarged. Lungs were not fully collapsed and exhibited 10 to 40% pale red cranioventral consolidation. Histopathologically, typical lymphohistiocytic interstitial to bronchointerstitial pneumonia, chronic lymphadenitis, severe lymphoid depletion, and basophilic intracytoplasmic inclusions were noted in the most lymphoid tissues. Porcine circovirus panicles were observed in the inguinal lymph node of the pigs by electron microscopy. Porcine circovirus type 2 (PCV2) antigens or viral DNAs were detected in the lesions of all pigs using immunohistochemistry or PCR. Two PCV2 were isolated from a homogenate of pooled lung and lymph node in 2 of the 5 pigs. Additionally, antigens of porcine reproductive and respiratory syndrome virus (PRRSV) and Hemophilus (H.) parasuis were also detected by immunofluorescent antibody test. Serologically, 55% of randomly selected sows and fattening pigs was serum antibody positive to PCV2 by an indirect fluorescent antibody (IFA) test and approximately 18 % of animals in the herd were serologically pooitive by the ELISA kit for PRRSV. To our knowledge, this is the first report of PMWS co-infected with PCV-2, PRRS, and H. parasuis in Korea.

• Korean Journal of Veterinary Service
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• v.27 no.2
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• pp.139-146
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• 2004

This study was carried out to investigate the prevalence of pocine circovirus type 2(PCV2) infection and post-weaning multi systemic wasting syndrome(PMWS) of swine in Gyeongbuk province from June to December in 2003. Gyeongbuk Veterinary Service Laboratory had tested PCV1 and PCV2 by the PCR method against 210 infected pigs of 105 farms, which were requested diagnosis of disease and investigate compositive infections with bacterial disease. The following results were obtained; 1. Among 210 pigs, The pigs infected with PCV1 were 134(63.8%) heads and with PCV2 were 143(68.1%) heads. 2. Using PCR, the rate of PCV1 infection of 105 farms which were requested of diagnosis of disease is positive in 75(71.4%) farms and 78(74.3%) farms were positive in PCV2, and compositive infections of PCV1 and PCV2 were 75(71.4%) farms. 3. According to age of requested pig, the frequency of PCV infection rate was following, the pig under 4 weeks of age were 28.6% in PCV1 and PCV2, respectively, and the pig of 4-7 weeks of age were 58.6% in PCV1 and PCV2, respectively. The pig of 8-11 weeks of age were 73.1% in PCVl and 74.6% in PCV2, the pig of 12-18 weeks of age were 80.9% in PCV1 and 88.1% in PCV2. 4. In the distribution of compositive infection with bacterial disease related to PCV2 among requested samples, PCV2 infection was 39.7% in 78 cases, two kinds of compositive infection was 38.5%, three kinds of compositive infection was 18.1% and four kinds of complex infection was 3.9%.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.31-31
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• 2003

Porcine circovirus (PCV) is the smallest virus that replicates autonomously in mammalian cells. PCV2 is recongized as the casual agent of postweaning multisystemic wasting syndrome (PMWS).[1] Although the role of PCV2 in reproductive failure requires further clarification, there have been several reports of PCV2-associated reproductive failure. Consistent clinical signs of affected farms include elevated abortion, stillbirths and fetal mummification. The objective of this study was to determine the prevalence of PCV2 in aborted fetuses and stillborn piglets. Second objective was to determine the distribution of PCV2 DNA and antigen in aborted fetuses and stillborn piglets by in situ hybridisation and immunohistochemistry. (omitted)

• Feed Journal
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• v.4 no.1 s.29
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• pp.118-125
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• 2006

국내 돼지 사육두수는 '04년 초 PMWS (이유후전신소모성증후군), PED (유행성설사병) 등 질병발생, 작년 여름 폭염 피해 및 분뇨처리 문제 등으로 2005년 9월말 8,993천두 수준으로 전년도 같은 기간보다 감소한 추세이다. 돼지고기 생산도 소비자의 구매 요구에 따라야 하는데, 국민소득 증대와 안전돈육에 대한 관심고조로 브랜드 개념이 돈육 시장에서도 거론되는 추세이다. 이런 시대적 요청에 따라 정부에서도 브랜드돈육 생산자 경영체 육성에 많은 노력을 기울이고 있다. 2005년에는 농림부와 농협중앙회가 주관한 제3회 우수 축산물 브랜드 경진대화를 개최한 바 있고, 2004년에는 「소비자 문제를 연구하는 시민의 모임」이 한우 9개소, 돼지 10개소를 우수 축산물 브랜드 생산업체로 인증하였다. 금후에도 브랜드 인증과 관련된 사업은 정부에서 지속적으로 추진할 전망이므로 양돈 생산농가와 업체 등 경영체에서는 브랜드 돈육 생산에 관한 노력을 꾸준히 실행해야 할 것으로 생각된다. 브랜드 돈육 생산은 종돈, 사료, 사양기술 등을 통일하고, 돼지고기의 품질을 높이며, 돈육을 소비자의 식탁까지 안전하게 유통시키고, 브랜드관리에 최선을 다하는 체계화된 일련의 사업이라 할 수 있다. 이런 시점에서 우수 축산물 브랜드 현황 및 조성 방안에 대하여 살펴볼까 한다.

• Korean Journal of Veterinary Service
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• v.26 no.2
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• pp.163-184
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• 2003

This study was conducted to survey the farm which suffered from disease similar to classical swine fever(CSF) in Gyeongbuk province. Clinical signs appeared first in a few number of growing pigs which showed specific signs of diarrhea, depression, sleepiness, and reluctance to get up or to eat. Younger piglets may have appeared chilled, shiver and huddle together. As the disease progresses the affected pig's skin went red and purple. In histopathological signs, there were many haemorrhages throughout the body and larger haemorrhages in some organs such as lymph nodes. And there is a precipitous fall in the number of circulating leukocytes in the blood. In spite of insisting of farmer which did not vaccinate to classical swine fever, significant antibody production was detected in these affected pigs at enzyme-linked immuonsorbent assay. According to the above results at first glance, these affected pig suspected with CSF in clinical signs and histopathological lesions only. Because the symptoms and post-mortem picture were very similar to CSF, these false positive results would have been dangerous to diagnostician. But by reverse transcriptase polymerase chain reaction(RT-PCR) and comparative nucleotide sequence analysis, the disease was correctly diagnosed with post-weaning multisystemic wasting syndrome(PMWS) and porcine reproductive and respiratory syndrome(PRRS) compoundly. And the antigen which were detected the lesion similar to CSF virus, was confirmed with LOM vaccine strain of CSF. In most national CSF eradication program and in countries which are free of the CSF virus, vaccination against CSF is not practiced and generally is not allowed. But now in Korea, routine vaccination is practiced because of outbreaking the CSF repeatedly. When CSF is diagnosed the whole herd and other in contact animal are slaughtered continuously.