• 농업과학연구
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• 제38권1호
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• pp.45-50
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• 2011

This study was conducted to investigate the farm situation about bovine leukemia virus(BLV) infection that greatly influence productivity in dairy cattle and compare the accuracy of diagnosis for BLV infection between PCR and ELISA techniques. Blood samples of 193 heads from 5 herds in Chungnam and Chungbuk area were used to analyze BLV gene and serum, and the results were obtained as follows. The amplified BLV gene in dairy cattle by PCR technique resulted in 226 bp, 596 bp and 434 bp, respectively, for gag, pol and env, which were well amplified. The infection rates of BLV virus diagnosed by PCR and ELISA techniques ranged from 80.55 to 100% and from 22.22 to 86.95%, respectively, and the infection rates among 5 herds were significantly different in both methods (P<0.05). Further, the average infection rates of 5 herds were 87.05 and 63.21%, respectively, for PCR and ELISA techniques. Kappa statistics for examining consistency of diagnosis by PCR and ELISA techniques showed 0.246, which represents low consistency. Consequently, PCR based BLV technique was considered as a corrective measure for diagnosis of BLV infection in Holstein dairy cattle.

• 대한수의학회지
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• 제55권1호
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• pp.53-56
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• 2015

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis. This study was conducted to clarify the molecular characteristics of BLVs obtained from a specific region in Korea. Proviral BLVs were detected in anti-BLV antibody-positive blood samples by PCR. Env and gag fragments were sequenced and compared to previously published reference sequences. Analysis of the env gene sequence revealed that the YI strain was highly similar to genotype 1, including United States and Japanese strains. The gag gene sequence had the highest degree of similarity with a Japanese strain.

• 대한의생명과학회지
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• 제10권1호
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• pp.55-63
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• 2004

Bovine leukemia virus (BLV) is a causative agent for lymphoma disease in cattle including cows worldwide. BLV shares similar virion structure and characteristics with other retroviruses. The pol gene of the BLV genome produced reverse transcriptase (RT) and integrase (IN) for important roles for BLV genome integration into host cell chromosomes that is known to be coded in the 3' side of the BLV pol gene (one third portion). In this study, we have sequenced 978 bp in the 3' side of the BLV pol gene from BLV 10C3 in order to determine the BLV IN region of it. And we compared it to the nucleotide sequences of an Australian BLV isolate. As a result, nucleotide sequences of the IN region of the Korean-type BLV pol gene were mutated at a rate of 3.7%. We can confirm that the typical mutations are such as Arg (AGG) $\rightarrow$ Lys (AAG), Thr (ACG) $\rightarrow$ Met (ATG), Ile (ATT) $\rightarrow$ Val (GTT), Asn (ACC) $\rightarrow$ His (CAC), Phe (TTT) $\rightarrow$ Leu (TTG) and Asn (ACC) $\rightarrow$ Asp (GAC). From the analysis of the sequencing data, we were able to determine the zinc-finger-like "HHCC" motif in the amino terminus of BLV IN, that was H-$X_3$-H-$X_{25}-C-X_2$-C. It was also found the DD35E motif in the IN catalytic domain as D-$X_{56}$-D-$X_{35}$-E. It fits very well to the consensus sequences of retroviral IN as well as HHCC motif.

• Asian-Australasian Journal of Animal Sciences
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• 제18권5호
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• pp.728-733
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• 2005

The frequency and distribution of lymphoma caused by bovine leukemia virus (BLV) infection in various organs were investigated. Lymphoma samples were obtained from slaughtered cattle or from cattle submitted to the National Veterinary Research and Quarantine Service, Korea. Thirty female Holstein-Friesian dairy cattle aged over three years with the BLV-associated lymphoma were studied. None of the Korean native cattle (Hanwoo) had lymphoma in this study however. Lymphoma tissues were gray to pink in color, soft in consistency, and bulged from the cut surface. In advanced lymphoma tissues, there was great variety in the appearance of involved structures due to hemorrhage, necrosis, and/or calcification. Neoplastic tissues were observed in lymph nodes in all lymphoma cases. Intestine (96.4%), heart (88.9%), stomach (73.1%), and diaphragm (62.5%) were frequently involved with lymphoma. However, there was no lymphoma detected in liver. Large neoplastic masses, sometimes reaching the size of over 20 cm, were found in the abdominal cavities. It is suggested that metastasis of lymphomas occurs mainly via lymph based on gross observations; neoplasia may have been initiated in the serosal surface of the lung, heart, peritoneum, and numerous hollow organs in the abdominal cavity. Also many organs in the abdominal and thoracic cavity were affected by neoplastic tissues simultaneously. Characteristics observed in this study could be used as criteria to differentiate BLV-associated lymphoma from other nodular lesions in the slaughterhouse and as fundamental data to make clear the mechanism of metastasis or pathogenesis of EBL.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
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• pp.250.1-250
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• 2000

No Abstract, See Full Text

• 대한수의학회지
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• 제45권2호
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• pp.239-244
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• 2005

Hematologic investigations were made on the blood samples taken from bovine leukemia virus (BLV)-seropositive Holstein-Friesian cattle in Korea, and their absolute lymphocyte count was compared with that of BLV-seronegative cattle. The incidence of persistent lymphocytosis (PL) was also determined. The normal bovine lymphocyte count was established on the basis of studies of 656 blood samples taken three times from 297 seronegative animals aged from 0~6 months to over 5 years at 5~6-month intervals. The data were examined according to 7 age groups of samples placed into their respective age groups. A peak in average total count was reached at 6~12 months ($5.36{\times}10^3/{\mu}l$) and thereafter the count declined continuously until over 5 years ($3.17{\times}10^3/{\mu}l$). From the results, 99.74 percent limits were calculated, and the upper limit of the range was chosen as the cutoff point for lymphocytosis. A PL was defined as a lymphocyte count that exceeded the above 99.74 percent limits and persisted over an interval of at least three months. The criterion for PL was applied to classifying 515 blood samples obtained four times from 189 seropositive animals without clinical signs at 5~7-month intervals. It was found that 54 (28.5%) of seropositive animals were with PL; cattle with PL were in age groups of 2~3 years to over 5 years.

• 대한수의학회지
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• 제29권2호
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• pp.115-121
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• 1989

1983년(年)부터 1985년도(年度)까지 사이에 일본(日本) Saitama현(縣) 각소도시근교(各小都市近郊)의 낙농장(酪農場)에서 사육(飼育)되는 2,407두(頭)의 유우(乳牛)를 대상(對象)으로 BLV(bovine leukemia virus) 감염여부(感染與否)를 혈청학적검사(血淸學的檢査)(agar-gel immunodiffusion test)를 실시(實施)한 결과(結果) 평균양성율(平均陽性率)은 4.9%이었고, 연령(年齡)이 증가(增加)함에 따라 2.6%에서 부터 9.8%까지 양성율(陽性率)이 있으며, 동일지역(同一地域)에서도 조사낙농장별(調査酪農場別)로 양성율(陽性率)은 큰 차(差)가 있었다. 본조사연구(本調査硏究)의 결과(結果)를 BLV감염(感染)에 대한 수의역학적(獸醫疫學的) 기초자료(基礎資料)로 제시(提示)하는 바이다.

• 대한수의학회지
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• 제30권3호
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• pp.333-341
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• 1990

To investigate bovine leukosis virus (BLV) infection in the cattle rearing in a dairy farm where a case of bovine lymphosarcoma had been identified several years ago, the 196 Holstein cattle including newborn calves to 12 years of age were tested. The BLV antibody test and peripheral lymphocyte count for bovine leukosis were carried out by the immunodiffusion (ID) test and Bendixen's Kep. These tests were performed 2 to 4 times at the interval of 3 to 5 months. The observed results were as follows: 1. The positive rates of BLV-antibody in the 1st, the 2nd, the 3rd and the 4th tests were 23.3%, 28.1%, 49.0% and 55.7%, respectively. The conversion rates from negative to positive in the 2nd, the 3rd and the 4th tests were 8.9%, 41.4%, and 20.0%, respectively. Results showed that the highest conversion rate was observed at the 3rd test which was conducted after winter. The highest positive rate by ID test were observed in 4 year old cattle in the 1st and 2nd tests, and in 2 year old herd in the 3rd and 4th tests. 2. In hematological test by Bendixen's Key, the positive and suspicious rates in the 1st, the 2nd, the 3rd and the 4th tests were 5.8 and 7.8%, 8.3 and 6.6%, 8.7 and 10.1%, 10.8 and 19.6% respectively. Results showed that the positive and. suspicious rates increased in course of time. 3. 70 to 100% of the positive cattle in hematological test were positive for BLV-antibody test. All of 13 cattle with persistent lymphocytosis (PL) were also positive for BLV-antibody, indicating the high relationship between PL and BLV-antibody. 4. The number of total leukocytes and absolute lymphocytes in the BLV-antibody positive cattle appeared significantly higher than those of the negative cattle. The markedly increased cell counts were observed in the cattle over one year old. 5. The mean of total leukocytes and absolute lymphocytes in the negative cattle for BLV-antibody increased slightly after sero-conversion into positive. 6. In the clinical examinations during experimental periods, none of the 72 positive cattle for BLV-antibody showed any lesions for bovine leukosis.

• 대한수의학회지
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• 제45권3호
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• pp.391-398
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• 2005

Several studies have been performed on the bovine leukemia since bovine leukemia virus (BLV) had been detected in 1982 in Korea. We have conducted histopathological study on the bovine lymphoma caused by BLV because only limited results were reported on the pathological characterization of lymphoma. Lymphoma tissues were obtained from cattle necropsied and slaughtered during a designated period. Lymphoma was classified histopathologically according to the National Cancer Institute Working Formulation. Leukotic tissues consisted of fairly uniform sheets of closely packed medium to large lymphocytes without any architectural arrangement in all 30 cases. Twenty five cases belong to diffuse large cell type, while three cases were diffuse mixed cell type, and two cases were immunoblastic large cell type among 30 cases. Follicular type lymphoma was not detected in this study. The mitotic index of tumor cells showed average 2.5 in the field of 400X. Nuclear cleavage was detected in 53% of cases. Multi-nucleated cells were detected among tumor cells in 30% of lymphoma cases. In conclusion, the most common morphologic cell type of bovine lymphoma in Korea was a diffuse large cell type with multinucleated cells and nuclear cleavages.

• Current Research on Agriculture and Life Sciences
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• 제1권
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• pp.195-199
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• 1983

우백혈청(牛白血病)virus에 대한 혈청항체의 측정(測定)을 위한 간접효소면역법(間接酵素免疫法)(ELISA)의 확립(確立) 및 ELISA법(法)의 감도(感度)를 알기 위하여 한천(寒天) gel 면역확산법(免疫擴散法)(ID)과 비교검토(比較檢討)하였으며 한우(韓牛), 유우(乳牛) 및 육우(肉牛)등 264두(頭)의 혈청(血淸)을 공시(供試)하였다. 혈청(血淸)을 가(加)하지 않은 공(孔)의 흡광치(吸光値)(C)로서 혈청치(血淸値)를 제(除)한 후, 표준(標準)BLV항체흡성혈청치(N)로서 피검혈청치(被檢血淸値)(T)를 나눈치(値)(T-C/N-C)가 1.5이상(以上)인 것을 BLV항체 양성(陽性)으로 하였을 때 gp-ID의 성적(成績)과 98.5%(259/263)가 일치(一致)되었다. gp-ID 향성혈청(陽性血淸) 145예(例)중 144예(例)가 ELISA 양성(陽性)으로 99.6%, gp-ID 음성혈청(陰性血淸) 118예(例)중 115예(例)가 ELISA음성(陰性)으로 97.5%가 일치(一致)되었다. 이상에서와 같이 gp-ID용(用)의 BLV 항원(抗原)을 사용한 ELISA법(法)을 gp-ID와 동등(同等) 또는 더 감도(感度)가 우수한 BLV의 혈청항체측정법 임이 입증되었으며 실용성(實用性)이 충분(充分)하다고 사료(思料)된다.