이유자돈 전신소모성증후군 이환 자돈에서의 바이러스성 원인체 검색 및 porcine circovirus 2 분리동정

박최규,김현수,Park, Choi-Kyu,Kim, Hyun-Soo 대한수의학회 2004 大韓獸醫學會誌 Vol.44 No.4

To detect viral agents and isolate porcine circovirus 2 (PCV2), 60 samples of lung and lymph node were collected from 5 to 12 week-old pigs that had showed clinical signs of postweaning multisystemic wasting syndrome (PMWS). Polymerase chain reactions (PCRs) were conducted to identify the viral pathogens including PCV1, PCV2, porcine parvovirus (PPV) and porcine reproductive and respiratory syndrome virus (PRRSV) that have been considered to be the causal agents of PMWS. Among 60 samples, PCV 2 was detected from 57 samples but no PCV 1 was detected. PRRSV and/or PPV were also detected from 27 (47.4%) samples and 1 (1.8%) sample of these 57 PCV 2-positive samples, respectively. Tissue homogenates were inoculated onto PCV-free PK-15 cell monolayers. Seven isolates were confirmed as PCV 2 by multiplex PCR, indirect immunofluorescence assay, and transmissible electron microscopy. These date suggest that PRRSV is a major cofactors causing PMWS in pigs that were infected with PCV2 in Korea.

돼지 생식기호흡기증후군 바이러스항체 검색에 있어 간접형광항체법(IFA) 과 효소면역법(ELISA)의 진단효율 비교

박최규,류영수,이창희,정종욱,Park, Choi-kyu,Lyoo, Young-soo,Lee, Chang-hee,Jung, Jong-wook 대한수의학회 1998 大韓獸醫學會誌 Vol.38 No.2

An establishment of effective control measures to PRRSV infection in swine industry depends on a sensitive and specific diagnosis to detect either viral antigen and/or antibodies to PRRSV. Several diagnostic methods are available to detect antibodies against PRRSV, including IPMA, IFA and ELISA tests have been successfully developed. Sensitivity of the indirect immunofluorescent assay in MA-104 cells using Korean field isolate PL96-1 was superior to that of VR-2332 and field isolate PL96-2. Sensitivity and specificity of the IFA test with PL96-1 were comparable to those of commercial ELISA test kit but ELISA test was more sensitive for the detection of declining antibodies to PRRSV in finishing pigs. In this study we concluded that IFA and ELISA test could be utilized to detect antibodies to PRRSV and the results generated from these two tests were comparable and there were no significant difference between these two tests.

RT-PCR for detection of group A, B and C porcine rotaviruses

박최규,류영수,Park, Choi-kyu,Lyoo, Young-soo,Paul, Prem S. The Korean Society of Veterinary Science 1998 大韓獸醫學會誌 Vol.38 No.1

본 연구에서는 돼지 로타바이러스의 혈청형 A, B 및 C를 동시에 진단할 수 있는 RT-PCR 기법을 개발하였다. 각각의 혈청형에 특이적인 primer를 이용하여 RT-PCR 기법으로 분변시료에서 직접 바이러스 동정을 실시한 결과, 23건의 로타바이러스 감염 분변 시료에서 13건이 혈청형 A, 3건이 혈청형 B, 2건이 혈청형 C로 나타나 국내에서도 A, B 및 C형의 돼지 로타바이러스가 공히 발생하고 있음을 확인하였으며, 발생분포는 외국의 예와 유사하였다. 이 RT-PCR기법은 돼지 로타바이러스의 주요 혈청형인 A, B 및 C형의 동시감별진단법으로 이용될 수 있을 것으로 판단된다.

돼지 생식기호흡증후군 바이러스의 항체분포 및 역학조사

박최규,장정호,강영배,이창희,류영수,김현수,Park, Choi-kyu,Chang, Chung-ho,Kang, Yung-bae,Lee, Chang-hee,Lyoo, Young-soo,Kim, Hyun-soo 대한수의학회 1999 大韓獸醫學會誌 Vol.39 No.1

A nation wide sero-epidemiological survey of porcine reproductive and respiratory syndrome(PRRS) was carried out to analyze the current status of the PRRS virus infections in the field using the indirect immunofluorescent antibody assay(IFA) with the field isolate PL96-1. Since the first report of the antibody detection to PRRSV in 1993, the prevalence of seropositive pigs has increased dramatically and the data indicate that over 21% of the pigs and around 60% of the farms showed seropositives to the PRRS virus. A slightly higher positive rate was recognized in breeders than fattenings and it might be due to the higher age at the time of testings. No significant regional differences were detected in the sero-epidemiological survey. Higher sero-positive rate in growers indicates that PRRSV infection in the field was common after weaning(around 40 days). However, the number of seropositive pigs were declined in fattening pigs. Sows showed around 26% of sero-positive rate that there is a higher chance of continuous virus circulation in the infected farms. Low rate of sero-positivity in boars(9.8%) implies that there is high demand in proper control measures to prevent virus spreading through breeding procedures such as natural or artificial insemination. Therefore it was concluded that PRRSV infection in domestic swine herds is endemic and the positive rate and economic loses will be increased by spontaneous infections in naive farms.

혈청학적 분석을 통한 돼지 생식기호흡기증후군의 농장단위 감염유형

박최규,윤하정,이창희,정병열,이경기,김현수,Park, Choi-Kyu,Yoon, Ha-Chung,Lee, Chang-Hee,Jung, Byeong-Yeal,Lee, Kyoung-Ki,Kim, Hyun-Soo 대한수의학회 2008 大韓獸醫學會誌 Vol.48 No.1

Porcine reproductive and respiratory syndrome (PRRS) is the most economically important viral infectious disease in pig populations worldwide. This study was conducted to better understand the epidemic and dynamics of PRRS virus (PRRSV) on each farm and to evaluate the risk of PRRSV infection in Korea. Interviews with pig farmers were carried out to obtain PRRS vaccination programmes in 60 pig farms throughout Korea. Blood samples were also collected from the 59 pig farms to investigate outbreak patterns of each farm. Vaccination against PRRS was performed in 16.7% farms for breeding pigs and 8.3% of farms for nursery pigs. According to the seroepidemiological analysis, 56 (94.9%) out of 59 farms were considered to be affected by PRRSV infection. The results revealed that 68.9% of sows tested were seroconverted and interestingly, gilt herds had the highest seropositive rate (73%), suggesting that gilts may play a key role in PRRSV transmission in sow herds. Among the PRRS-affected piglet herds, 33 (55.9%), 14 (23.7%) and 6 (10.2%) farms were initially infected with PRRSV during the weaning, suckling and nursery period, respectively. It seems likely, therefore, that PRRSV infection predominantly occurs around the weaning period in piglet herds. Based on antibody seroprevalence levels in both sow and piglet groups, we were able to classify patterns of PRRSV infection per farm unit into 4 categories; category 1 (stable sow groups and non-infected piglet groups), category 2 (unstable sow groups and non-infected piglet groups), category 3 (stable sow groups and infected piglet groups), and category 4 (unstable sow groups and infected piglet groups). Our data suggested that 43 (72.9%) farms were analysed to belong to category 4, which is considered to be at high-risk for PRRS outbreak. Taken together, our information from this study will provide insight into the establishment of an effective control strategy for PRRS on the field.

2002년 한국에서 발생한 돼지콜레라의 역학적 특성

박최규,송재영,위성환,이은섭,윤하정,문운경,최은진,남향미,Park, Choi-Kyu,Song, Jae-Young,Wee, Sung-Hwan,Lee, Eune-Sub,Yoon, Hachung,Moon, Oun-Kyeong,Choi, Eun-Jin,Nam, Hyang-Mi 대한수의학회 2006 大韓獸醫學會誌 Vol.46 No.2

This paper described the epidemiological characteristics of 2002 outbreak of classical swine fever (CSF) in Korea. A total of thirteen CSF-infected farms could be classified into two clusters according to the location and time of outbreak. Two farms located in the same county of Gangwon province and 11 farms located in several different districts of Incheon metropolitan/Gyeonggi province were identified as CSF-infected from April 16 to 30 and from October 7 to December 21 in 2002, respectively. As the result of epidemiological analysis, the two clusters of outbreaks were turned out to be independent epidemics which had different sources of virus introduction. Three farms were found to have been infected primarily; one located in Cheolwon county of Gangwon province and two located in Kangwha county of Incheon metropolitan area. The most likely factors of virus introduction into these primary infected farms were considered to be direct or indirect contact by foreign workers and/or owners of the infected farms who had come back from traveling in China before outbreaks. This was supported by the genetic typing of CSF viruses isolated from the pigs of infected farms. All the virus isolates of 2002 outbreak were found to be genetic type 2, whereas the viruses isolated before 2000 were type 3 and the reference strains, such as attenuated live vaccine virus (LOM strain) and high virulent challenge virus (ALD strain), were type 1. Accordingly, we concluded that the 2002 CSF outbreak must have been caused by a newly introduced virus from overseas and the type 3 virus must have been eradicated after the last outbreak of 1999 by the national CSF eradication campaign which were implemented since 1996. Based on the combined analysis of epidemiological data and genetic typing, the transmission routes of classical swine fever virus were found to be the movement of vehicles (60%) and persons (10%), neighbourhood spread (20%) and unknown (10%). It is expected that the analyzed data and findings of classical swine fever outbreak epidemic could be very useful to establish the disease control and eradication program for the country in the future.

2003년 한국의 돼지콜레라 전국적 확산에 대한 기술역학

박최규,이은섭,윤하정,위성환,송재영,문운경,최은진,김현수,이주호,안수환,Park, Choi-Kyu,Lee, Eune-Sub,Yoon, Hachung,Wee, Sung-Hwan,Song, Jae-Young,Moon, Oun-Kyeong,Choi, Eun-Jin,Kim, Hyun-Soo,Lee, Joo-Ho,An, Su-Hwan 대한수의학회 2006 大韓獸醫學會誌 Vol.46 No.3

In March 2003, classical swine fever (CSF) infection was reported in a piggery located at Iksan city, Jeollabuk-do in Korea. Subsequently, a total of 72 infected farms were confirmed between March and December, 2003. Based on epidemiological investigation of the earlier confirmed infected farms, the source of infection was shown to be from a breeding farm. Targeted surveillance of 82 piggeries that had acquired pigs from this breeding farm showed 44 piggeries were infected with CSF virus. CSF virus was introduced into this breeding farm by movement of selected breeder pigs from its 12 contracted farms which were located in areas that had been affected by CSF epidemic in late 2002. CSF had then spread through out the country mainly by direct transmission through the sale and movement of pigs from this breeding farm. Consequently, 47 (62%) among 72 CSF affected farms were associated, directly and indirectly, with this breeding farm. This study showed that inadequate control for breeding farms and transport restriction in CSF outbreak areas resulted in the nationwide spread of CSF and the failure of the eradication campaign that has been underway for several years by the Korean animal hygiene authority as well as the fanners. Improvements of control policy through further research of the 2003 CSF epidemic will be needed to reestablish the Korean CSF eradication program in the future.

국내 25개 양돈장의 살모넬라 유병율 및 감염유형

박최규(Choi-Kyu Park),김희정(Hee-Jung Kim),김진현(Jin-Hyun Kim),조재근(Jae-Keun Cho),김영화(Young-Hwa Kim),정윤수(Yoon-Soo Jung),배채운(Chae-Wun Bae),박준철(Jun-Cheol Park),김기석(Ki-Seuk Kim) 한국생명과학회 2013 생명과학회지 Vol.23 No.10

본 연구에서는 25개 양돈장의 사육돼지를 대상으로 혈청학적 및 미생물학적 모니터링을 실시하여 살모넬라의 유병율과 감염 양상을 분석함으로써 향후 한국 양돈장의 살모넬라 제어 프로그램 구축의 기초자료로 활용하고자 하였다. 25개 양돈장의 모돈과 사육단계별 돼지 혈청 총 848두에 대한 항체검사 결과, 전체 항체 보유율은 28.4%로 나타났으며, 사육단계별로는 모돈의 항체양성율이 83.1%로 가장 높았고, 20일령 이후 모체이행항체가 소실되고, 농장에서의 사육기간이 길어질수록 살모넬라에 노출되는 빈도가 높아지는 것으로 나타났다. 조사대상 25개 양돈장의 모돈군은 최소한 1두 이상의 항체 양성모돈을 보유하고 있어 향후 우리나라 살모넬라 방역에 있어 종돈장의 살모넬라 감염 통제 및 음성 후보돈 공급체계 확립이 가장 시급한 것으로 판단되었다. 25개 양돈장에서 채취한 사육단계별 돼지 분변에 대한 세균 분리 동정 결과, 혈청학적으로 감염유형인 16개 양돈장 중 3개 양돈장(12.0%)에서 살모넬라 균이 분리되었다. 이러한 결과는 양돈장 사육 돼지집단에 대한 살모넬라 감염상황을 정확하게 파악하기 위해서는 세균검사법만으로는 한계가 있으며, 돈군 내의 준임상감염축 또는 잠복감염축을 진단할 수 있는 혈청검사를 병행해야 함을 시사해준다. 또한 향후 우리나라의 양돈장 살모넬라 통제 프로그램을 구축하기 위하여 다양한 양돈장 모니터링 기법을 개발하고, 현장 효용성을 확인하기 위한 확대 시험이 필요하다. The aim of this study was to determine the prevalence and infection status of Salmonella species (spp.) in 25 conventional pig farms by traditional fecal culture and serological methods to develop a Salmonella control program for Korean pig farms. The individual seroprevalence of Salmonella spp. in pigs reared in the 25 pig farms was 83.1% in sows and 6.4-32% in different aged pig groups, with the total seroprevalence 28.4% (141/848). The seroprevalence of the tested pigs increased in accordance with the decrease in maternal antibody and the rearing period on these farms. Of note, all the 25 pig farms contained at least two or more anti-Salmonella antibody-positive sows. In the fecal cultures Salmonella spp. were isolated only in three (12.0%, 3/25) of 16 serologically Salmonella-suspected farms (64.0%, 16/25), showing the limitation of the fecal culture method and the need for serum assays to understand the exact status of Salmonella infection in swine herds, which likely contain subclinically infected pigs or carriers. The results highlight the need to establish a supply system of Salmonella-free gilts for the promotion of a national Salmonella control program on swine farms in Korea. Further studies will be needed to develop an effective monitoring system for the implementation of a national Salmonella control program.

혈청역학적 분석을 통한 한국의 돼지 유행성 설사병 바이러스 감염양상

박최규(Choi-Kyu Park),박선일(Son-Il Pak) 한국생명과학회 2009 생명과학회지 Vol.19 No.9

To investigate the infection patterns of porcine epidemic diarrhea virus (PEDV) in Korean pig farms, a total of 4,768 swine sera samples from 159 pig farms were taken twice, in June (n=82) and October (n=77) in 2007. In each farm selected for the survey, 10 samples from breeding pigs and 4 from each of the 5 age groups (30, 60, 90, 120, and 150 days) were taken, and all serum samples were tested for PEDV by the serum neutralization test. The overall seroprevalence was 62.6% (2,983/4,768), with the highest prevalence in breeding pigs (93.5%, 1,485/1,589). The prevalence showed an increasing trend with increasing age (30.8, 27.2, 44.7, 61.6, and 71.2% respectively in the 30, 60, 90, 120, and 150 days age groups) (p<0.0001 for x² trend test). The association between age and PEDV prevalence was similar in both surveys, indicating that the infection of PEDV seemed to be occurring repeatedly in the farms surveyed. This inference could also be explained by the fact that prevalence in sows was very high despite low vaccination coverage, as they are continuously exposed to PEDV in potentially infected farms for a longer period. Based on the neutralizing antibody levels in sows and growing pigs, the majority of farms (91.8%, n=146 farms) were endemically infected with PEDV, and most of pigs seemed to be intensively infected with PEDV at around early growth (41.8%) and weaning (31.5%). On the other hand, serum neutralizing antibodies were not detected in pigs older than 30 days of age in farms classified as having no PEDV infection (n=13 farms), indicating the level of maternal antibody against PEDV is decreased on a non-detectable level before the piglet is 60 days old in the field situation. The results indicated that most farms surveyed in 2007 were affected with endemic PEDV infection. Therefore, a national monitoring and control program for the endemic type PEDV infection needs further attention.

우리나라 양돈장의 예방 접종 실태 조사

박최규 ( Choi Kyu Park ),정병열 ( Byeong Yeal Jung ),윤하정 ( Ha Chung Yoon ),이창희 ( Chang Hee Lee ),김현수 ( Hyun Soo Kim ) 한국수의공중보건학회 2007 예방수의학회지 Vol.31 No.3