재조합 baculovirus에 의한 아프리카 돼지콜레라바이러스 p12 단백질의 발현과 진단적 적용

최강석,최정업,김용주,Choi, Kang-Seuk,Choi, Cheong-up,Kim, Yong-Joo 대한수의학회 2005 大韓獸醫學會誌 Vol.45 No.1

African swine fever (ASF) is an infectious disease of domestic and wild pigs for which there is no vaccine in the world. A proper surveillance of viral activity and a timely response to ASF outbreaks depend upon the rapid diagnosis of ASF viral infection. Internationally prescribed enzyme-linked immunosorbent assay (ELISA) is a fast, sensitive test routinely used in the diagnosis of the ASF. However, inactivated whole ASF virus antigen used in this test is a tedious to prepare and has a risk of outside exposure of infectious virus by laboratory accident during the preparation. An ASF virus noninfectious recombinant antigen is a safe and easily produced alternative antigen for use in diagnostic assay. We have cloned the ORF O61R gene of the ASF virus to generate a recombinant baculovirus producing the p12 protein in insect cells under control of the polyhedrin promoter as non-fusion protein. When used in an indirect ELISA, the p12 antigen showed reactivity with all known ASF positive pig sera but not with negative pig sera. Our results indicated that the p12 protein would be one of alternative antigens for diagnosis of the ASF.

흰뺨검둥오리(Anas poecilorhyncha)에서 분리된 뉴캣슬병 바이러스의 특성

최강석,이은경,전우진,권준헌,양창범,Choi, Kang-Seuk,Lee, Eun-Kyoung,Jeon, Woo-Jin,Kwon, Jun-Hun,Yang, Chang-Bum 대한수의학회 2008 大韓獸醫學會誌 Vol.48 No.2

Newcastle disease virus (NDV) is the causative agent of a highly contagious and devastating Newcastle disease of poultry. A NDV (isolate DK1/07) was isolated from apparently healthy wild spot-billed ducks (Anas poecilorhyncha) captured at upper branch of the SapGyo Creek in Chungbuk province, Korea during early 2007. The DK1/07 isolate of minimum chicken embryo lethal dose killed all SPF chicken embryos within 60 h. The cleavage site of the F protein possessed the amino acid sequence $^{112}R-R-Q-K-R-F^{117}$, which is a motif characteristic of virulent NDV strains. The F protein-based phylogenetic analysis revealed that the DK1/07 duck isolate was included in the cluster of genotype VIId and most closely related to recent NDV isolates obtained from chicken farms in Korea. Epidemiological importance of virulent NDV from wild duck is discussed.

한국호흡기형 닭전염성기관지염 생독백신주의 작성

최강석,전우진,이은경,계수정,박미자,권준헌,Choi, Kang-Seuk,Jeon, Woo-Jin,Lee, Eun-Kyoung,Kye, Soo-Jeong,Park, Mi-Ja,Kwon, Jun-Hun 대한수의학회 2011 大韓獸醫學會誌 Vol.51 No.3

An attenuated vaccine strain AVR1/08 of Korean respiratory type of infectious bronchitis virus (IBV) was developed by 89th passages of IBV D85/06 strain in chicken eggs. The AVR1/08 strain had higher virus titer at least 20 times ($10^{1.3}$) than the parent virus D85/06 by egg inoculation method. The AVR1/08 strain had a single point mutation (S to Y) at position 56 of spike protein of IBV compared to parent virus IBV D85/06 strain. The mutation was observed consistently at viruses after 47th passage in chicken eggs. The AVR1/08 strain showed no virulence even after 6 passages in chickens and all chickens inoculated induced anti-IBV antibody 14 days after vaccination. The AVR1/08 strain had broad protective efficacy against QX type Korean nephropathogenic virus (Q43/06 strain), KM91 type Korean nephropathogenic virus (KM91 strain) and Korean respiratory virus (D85/06 strain). In contrast, Massachusetts (Mass) type attenuated vaccine strain H120 showed protection of 37.5 to 50% against these three viruses. Our results indicate that the AVR1/08 strain has potential as an attenuated vaccine effective in controlling IBVs circulating in Korea.

최근 국내에서 유행하는 뉴캣슬병 바이러스의 특성 고찰

최강석(Kang Seuk Choi) 韓國家禽學會 2010 韓國家禽學會誌 Vol.37 No.1

국내에서는 2000년대 초까지 3년 내지 5년 간격으로 주기적인 뉴캣슬병 대유행을 겪어왔다. 이 시기에 최소한 5개의 다른 유전자형의 뉴캣슬병 바이러스가 국내 뉴캣슬병 대유행과 관련이 있었다. 1970년대 이전엔 유전자형 Ⅲ형, 1980년대 중반에 유전자형 Ⅴ형, 1980년대 말에서 1990년대 초에는 유전자형 Ⅵ형, 1990년대 중반에 유전자형 Ⅶa형, 그리고 1990년대 말부터 2000년대 초에는 유전자형 Ⅶd형이 관련되어 있었다. 최근 국내에서 유행한 뉴캣슬병 바이러스는 중국과 일본과 같은 인근국가와 지리적인 공통점을 보였다. 과거 유행했던 다른 유전자형과 마찬가지로, 유전자형 Ⅶd형 또한 내장친화성 강독 뉴캣슬병 바이러스였다. 현재 사용 중인 백신주와 최근 유행하는 Ⅶd형 바이러스간에 항원적 차이는 존재하지만, 시판 백신에 의한 방어 효능에는 문제가 없는 것으로 확인되었다. Newcastle disease (ND), caused by Newcastle disease virus (NDV), has caused periodic epidemics in Korea at an interval of 3 to 5 years until the early 2000s. At least five distinct genotypes of NDV have been responsible for epizootic episodes in Korea; genotype Ⅲ virus (before the 1970s), genotype Ⅴ (the mid-1980s), genotype Ⅵ (the late 1980s to early 1990s), genotype Ⅶa (the mid-1990s), and genotype Ⅶd viruses (the late 1990s to present). Recent epidemic strains of NDV (Ⅶd viruses) shared geographical features with neighboring countries such as China and Japan. These Ⅶd viruses as well as genotypes Ⅲ and Ⅴ viruses were viscerotropic and highly virulent for chickens. Antigenic variation occurred between Ⅶd field viruses and LaSota vaccine strain, as found in other epidemic strains in past in Korea. Nevertheless the commercial vaccine was considered to effectively protect vaccinated birds from mortality against Ⅶd viruses as well as other viruses belonging to genotypes Ⅲ and Ⅴ.

몽골에서 최초로 분리된 뉴캣슬병 바이러스의 분자생물학적 특성

최강석(Kang-Seuk Choi),이은경(Eun-Kyoung Lee),전우진(Woo-Jin Jeon),D. Batchuulon,R. Sodnomdarjaa,박미자(Mi-Ja Park),유예나(Ye-Nah Yoo),권준헌(Jun-Hun Kwon) 韓國家禽學會 2011 韓國家禽學會誌 Vol.38 No.2

몽골 산란계 농장에서 발생한 뉴캣슬병 사례로부터 뉴캣슬병 바이러스를 분리하고 그 특성을 조사하였다. 그 결과, 발생 농장 산란계 폐사계의 뇌 및 폐 조직으로부터 뉴캣슬병 바이러스 MN1/10 주가 분리되었다. 이 바이러스는 F 단백질 분절 부위가 특징적인 병원성 motif(RRQKRF)를 가지고 있었으며 종란 평균 치사 지수(MDT)가 54.7시간으로 강독형 NDV이었다. 또한 발생 농장 내 생존하고 있는 산란계에서 고역가의 NDV 특이항체가 검출되었다. 유적학적 계통 분석을 실시한 결과, 몽골 분리주는 ClassⅡ에 속하는 genotype Ⅶd 바이러스로 확인되었다. 유전학적 계통 분석 결과, 몽골 분리주는 몽골과 인접한 중국에서 유행하는 바이러스그룹(CN2)에 속하는 것으로 분류되었다. 우리의 연구 결과는 몽골에서의 뉴캣슬병 최초 발생은 동북아시아 지역에서 유행하는 강독형 NDV의 유입에 의해서 이루어졌음을 말해준다. The outbreak of Newcastle disease occurred for the first time at a commercial chicken farm near Ulaanbaatar, Mongolia in August 2010. Newcastle disease virus (NDV) obtained from infected chickens in Mongolia was characterized by biological and molecular biological approches. Mongolian NDV isolate killed all of chicken embryos within 60 h in the mean death time assay, indicating virulent for chicken. A genomic region of 695 nts between nts 1055 of the M gene and 508 of the F gene was amplified by RT-PCR and sequenced. The deduced amino acid sequence of the F protein cleavage site was ¹¹²RRQKRF¹¹?, which is a typical sequence of velogenic strains of NDV and is agreement with the result of the MDT assay. The sequence of the partial F gene (nts 47 to 435) was used for genotyping by phylogenetic analysis. The phylogenetic analysis showed that the Mongolian isolate was of genotype Ⅶ within classⅡ of NDV. Further phylogenetic analysis on the genotype Ⅶ strains revealed that the isolates placed in a genetic sublineage of Ⅶd and most closely related with velogenic strains of NDV circulating in Far-east Asian region especially China, suggesting the introduction of velogenic NDV into Mongolia from neighboring countries.

닭 도축장에서의 뉴캣슬병 바이러스 오염 실태 조사

최강석(Kang-Seuk Choi),이은경(Eun-Kyoung Lee),전우진(Woo-Jin Jeon),권준헌(Jun-Hun Kwon),이진화(Jin-Hwa Lee),성환우(Haan-Woo Sung) 韓國家禽學會 2011 韓國家禽學會誌 Vol.38 No.2

국내 도축장 및 도축장 출하 닭을 대상으로 NDV 오염 실태를조사하였다. 조사결과, 닭출하농장, 닭수송용차량, 도축장 현수실, 도축장 냉각수에서 각각 조사 대상건수의 13.0%, 13.3%, 16.0%, 10.8%에서 NDV가 분리되었다. 시기별로 보면 차량, 현수실, 냉각수 모두에서 7월에 가장 많이 바이러스가 분리되었다. Pathotyping RT-PCR을 실시한 결과, 이들 분리된 NDV 분리주는 모두 저병원성 NDV 양성 반응을 나타내었으며, F 단백질 분절 부위에 모두 ¹¹²GKQGR/L¹¹? motif를 가지고 있었다. 본 연구에서 분리된 NDV 분리주의 F 단백질 유전자를 분석하여 보았을 때, 조사한 NDV 분리주 25주 중 24주가 NDV V4주와 같은 유전적 cluster를 형성하였으며, 나머지 1주는 NDV Ulster 2C주와 같은 유전적 cluster를 형성하였다. 이와 같은 연구 결과로 보아 국내에서는 출하 닭, 수송 차량, 현수실, 냉각수 등 생산에서 도축 단계까지 일련의 과정에서 높은 빈도로 저병원성 NDV 오염이 이루어지고 있음을 알 수 있었다. We conducted a 10-month (March to October 2009) surveillance of Newcastle disease virus (NDV) in 13 slaughterhouses in Korea. NDV was isolated in 13.0%, 13.3%, 16.0%, and 10.8% of chicken farms, transport vehicles, hang rooms, and chilling water, respectively. Of NDV isolates from slaughterhouses, 37% were isolated in July. All NDV isolates were determined to be lentogenic viruses by RT-PCR-based pathotyping, and all NDV isolates had the ¹¹²GKQGR/L¹¹? motif at the cleavage site of the F protein. Phylogenetic analysis based on the hypervariable region of the F protein gene classified all 25 NDV isolates examined into genotype I within class Ⅱ. Of these, 24 were clustered together with the NDV V4 strain, while the remaining isolate was placed in the cluster belonging to the NDV Ulster 2C strain. Our results indicate that lentogenic NDV was a high-frequency contaminant in the serial process of ranging live birds to slaughtering at slaughterhouses.

국내 야생 조류에서의 뉴캣슬병 바이러스 항체분포율 조사

최강석(Kang-Seuk Choi),전우진(Woo-Jin Jeon),계수정(Soo-Jeong Kye),윤순식(Soon-Seek Yoon),정우석(Wooseog Jeong),김지예(Ji-Ye Kim),권준헌(Jun-Hun Kwon) 韓國家禽學會 2012 韓國家禽學會誌 Vol.39 No.2

Newcastle disease virus (NDV) infects a variety of birds with a wide range of clinical signs from asymptomatic to severe. During a 10-month period in 2011, a total of 1,024 sera from wild birds including 42 species of birds in 8 orders were collected and the seroprevalence of NDV in wild birds was evaluated by hemagglutination inhibition (HI) test. Evidence of NDV infection was observed in 12.6% (129/1,024) of wild birds with a maximum prevalence reported in Mandarin duck (27.8%, 32/115) followed by Mallard duck (20.8%, 57/274), Spot-billed duck (11.9%, 36/303), Pintail (2.9%, 1/34), Blacktailed gull (2.9%, 1/34), White-fronted goose (1.8%, 1/56) and Common teal (1.4%, 1/69). None of the other 35 species of wild birds were antibody-positive for NDV. Mandarin duck, Mallard duck and Spot-billed duck showed high sero-prevalance of 12.2% to 42% during winter season (November to March). Our results indicate that Mandarin duck, Mallard duck and Spot-billed duck might be natural reservoirs for NDV in Korea and the prevalence of NDV infection in wild birds displayed a seasonal pattern with high prevalence of NDV in winter season (November to March).

Vero 세포적응 뉴캣슬병 바이러스의 생물학적 특성

최강석(Kang-Seuk Choi),박미자(Mi-Ja Park),계수정(Soo-Jeong Kye),김지예(Ji-Ye Kim),권준헌(Jun-Hun Kwon) 韓國家禽學會 2012 韓國家禽學會誌 Vol.39 No.2

Newcastle disease virus (NDV) Kr005/V strain was generated through 55 serial passages of NDV Kr005 strain in Vero cells. The Kr005/V virus yielded high infective titers of 107.8 TCID50/mL in Vero cells and the infected cells showed cytopathic effects such as marked cell rounding, though less frequent syncytia. The Kr005/V virus was heat-stable and classified into the lentogenic type with a Mean Death Time (MDT) of 120h or greater while the Kr005 strain was heat-labile and velogenic (MDT of 49.6 h). Only the single amino acid substitution (T to S) was observed at position 433 of the HN protein of the Kr005/V strain, whereas no amino acid change was found in the F protein. The Kr005/V input virus correlated well (correlation coefficient r2=0.97) with the Kr005 virus when ten field sera were tested by virus neutralization test. The biological properties and usefulness of Vero cell-adapted Kr005/V virus were discussed.

육계 농장 깔짚에서의 주요 바이러스 병원체 오염 실태 조사

최강석(Kang-Seuk Choi),전우진(Woo-Jin Jeon),이은경(Eun-Kyoung Lee),권준헌(Jun-Hun Kwon),이진화(Jin-Hwa Lee),성환우(Haan-Woo Sung) 韓國家禽學會 2011 韓國家禽學會誌 Vol.38 No.3

A 5-month (May to November in 2009) monitoring program for five viral pathogens in litter, such as avian influenza virus A (AIV), infectious bronchitis virus (IBV), infectious bursal disease virus (IBDV), fowl adenovirus (FAdV), and chicken infectious anemia virus (CIAV) was conducted in 62 flocks at 31 broiler farms (two flocks in each farm) in Korea in 2009. Viral pathogens were examined twice (before and at the end of the rearing period) at 31 broiler farms, and included fresh litter (n = 16) and recycled litter (n = 15) farms. Thirty-seven viruses (14 IBVs, 2 IBDVs, 9 FAdVs, and 12 CIAVs) were isolated from 75% (12/16) and 73% (11/15) of fresh litter and reused litter farms during the period, respectively, indicating no difference in viral contamination rate between farms using new and reused litter. Of these isolates, three (two CIAVs and one IBDV) were isolated from recycled litter samples collected before the rearing period at three broiler farms, whereas the others (n=34) were isolated from fresh and recycled litter samples collected at the end of the rearing period. When the performances, involving viability, body weight, and feed conversion ratio, were compared, no significant differences were found between farms using fresh and recycled litter during the period.

깔짚 교체 및 재사용 육계농장 분리 대장균의 항생제 내성 양상

성환우,최강석,권혁무,이영주,Sung, Haan-Woo,Choi, Kang-Seuk,Kwon, Hyuk-Moo,Lee, Young-Ju 대한수의학회 2017 大韓獸醫學會誌 Vol.57 No.3

The isolation rate of Escherichia (E.) coli in poultry litter was investigated at 44 broiler farms, 20 that used fresh litter and 24 that used recycled litter. The patterns of resistance to antibiotics of the E. coli isolates were compared. In litter sampled before the rearing period, the isolation rate of E. coli was higher at farms that used fresh litter; E. coli was present in the litter in 94.5% (35 out of 37 flocks tested) of the farms that used fresh litter vs. 51.2% (21 out of 41 flocks) of the farms that used recycled litter. The susceptibility of the 93 isolates of E. coli to 13 antibiotics was studied. Before the rearing period, E. coli isolates from the farms that recycled litter showed higher resistance rates than isolates from farms that replaced litter with fresh litter. Comparing the antibiotic resistance patterns of isolates from litter sampled before and at the end of the rearing period, the antibiotic resistance rates at the end of the rearing period increased dramatically compared with rates before the rearing period.