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

• 한국임상수의학회지
• /
• 제27권4호
• /
• pp.402-406
• /
• 2010

Bovine leukemia virus (BLV) is a delta-retrovirus which causes chronic lymphocytosis in cattle. BLV infections have been divided into two groups such as enzootic bovine leukosis (EBL) and sporadic bovine leukosis (SBL) according to the clinical symptoms in infected cattle. The conventional detection method of BLV was hematological procedure which is determining lymphocytosis in the suspected animals. Recently several sensitive methods were developed to detect antibody to BLV and nucleic acid of the BLV from infected cattle. In this study we have compared the difference of positive rates between agar gel immunodiffusion (AGID) and enzyme linked immunosorbent assay (ELISA) which are using for BLV antibody detection methods. The positive detection rate of ELISA test was 7.4% greater than the positive rate of AGID. The discrepancy of the positive rate between ELISA and AGID were showed in the group of age over one year old to under three year old group. The result from each test agreed very well in the group of over 5 year old cattles. The serological test is very useful method to select the infected cattle for the eradication or control of the disease in the infected herd. But it has a limit by interference of the maternal antibody from the cow of under 6 month old. This study shows that 16.2% of these ages group showed BLV gene positive by polymerase chain reaction (PCR) method. The result suggests that ELISA test need to be used with PCR to clarify misinterpretation of positive animals by antibody response due to the natural infection from maternally derived antibody in calves of under 6 months old.

• 대한수의학회지
• /
• 제22권2호
• /
• pp.175-185
• /
• 1982

소백혈병(白血病)바이러스 봉입체단백(封入體蛋白)을 항원(抗原)으로 이용한 면역확산법(免疫擴散法)으로 전국에 산재해 있는 164개 목장(牧場)에서 사육중인 2003두(頭)의 유우(乳牛)에 대한 소백혈병(白血病)바이러스항체(抗體) 조사결과, 양성율(陽性率)은 충청도(忠淸道)가 41.8%로 가장 높았고, 전북(全北)은 24.4%로 가장 낮았다. 지역별(地域別) 양성율(陽性率)은 중부지역(中部地域)이 37.8%, 호남지역(湖南地域)이 27.2%, 영남지역(嶺南地域)이 28.0%, 그러고 영동지역(嶺東地域)이 25.2%였다. 전국의 평균 양성율(陽性率)은 29.8%였다. 혈청학적(血淸學的) 검사결과(檢査結果)를 분석(分析)하였던 바 양성율(陽性率)은 소의 연령(年齡)이 높을수록, 사육규모(飼育規模)가 클수록 높은 경향이 있었고, 소의 연령군(年齡群)이 6내지 8세에서, 사육규모(飼育規模)가 20내지 50두(頭)의 우군(牛群)에서 양성율(陽性率)이 가장 높였다. 중부지역(中部地域)에 사육중인 117두(頭)의 종모우(種牡牛)에 대해 조사한 결과 한우(韓牛)에서는 5.7%(4/70), 홀스타인 종모우(種牡牛)에서는 35.9% (14/39)의 양성율(陽性率)을 나타냈다. 우군별(牛群別)로는 혈청검사(血淸檢査)를 한 164개 우군(牛群)중에 양성우(陽性牛)가 전혀 없는 우군(牛群)이 17개군(個群)(10.4%), 20~40%의 양성우(陽性牛)가 있는 우군(牛群)이 42개(個)(25.6%)였고, 80%이상의 양성우(陽性牛)가 있는 우군(牛群)은 10개군(個群)(6.1%)이었다. 소백혈병(白血病)바이러스항체(抗體) 양성우(陽性牛)에서 분리(分離)한 임파구(淋巴球)를 phytohemagglutinin을 첨가한 배지(培地)에 단기배양(短期培養)한 후 BLV 형광항체(螢光抗體)를 이용하여 임파구(淋巴球)내의 BLV항원(抗原) 증명(證明)을 시도한 바, 양성우(陽性牛) 11두(頭)중 8두((頭)(72.7%)에서 특이(特異)한 BLV항원(抗原)이 규명(糾明)되었다. BLV 항체양성우(抗體陽性牛) 7두(頭)와 음성우(陰性牛) 4두(頭)에서 분리한 임파구(淋巴球)의 우태아비장세포(牛胎兒脾臟細胞)에 대한 syncytium 형성능(形成能)을 시험한 바, 양성우(陽性牛) 7두(頭) 중 5두(頭)(71.4%)의 임파구(淋巴球)가 syncytium을 형성(形成)하였다. 배양(培養)된 임파구(淋巴球)를 전자현미경(電子顯微鏡)으로 검사한 결과 6두(頭)의 양성우(陽性牛) 중 2두(頭)에서 90~110nm. 크기의 전형적(典型的)인 C형(型) 소백혈병(白血病)바이러스가 증명(證明)되었다.

• 대한수의학회지
• /
• 제30권3호
• /
• pp.343-348
• /
• 1990

Total 51 calves born from both 28 seropositive and 23 seronegative dams were subjected to study both prenatal and postnatal infections of bovine leukemia virus (BLV), and the duration of passive colostral antibody by means of immunodiffusion (ID) test. All calves were tested for precolostral and postcolostral periods by 16 months of age. The results were as follows: 1. Of 28 precolostral sera of the calves born from infected dams, one appeared positive, indicating in utero BLV infection from the dam. 2. BLV-antibody test for the postcolostral sera of the calves born from seropositive or seronegative dams showed that the colostral antibody of the calves disappeared from 2 to 6 months of age, and the increase of the number of seropositive calves initiated from 3 to 4 months of age indicated postnatal infection.

• 한국동물위생학회지
• /
• 제15권1호
• /
• pp.51-57
• /
• 1992

A serological survey was carried out for the detection of antibody of Bovine Leukemia Virus (BLV) in nothern parts of Chung Buk area. The results were summarized as followed. 1. The overall positive rate was revealed as high as 15% with 48 positive cases out of 319 heads examined. 2. According to age, cattle of 4 to 7 ages showed relatively higher positive rate of 15% than other ages. 3. Seasonal differences of positive rate were not recognized. 4. BLV antibody titer of scales of cattles that from 5 to 15 heads farm were the highest. 5. With the result of blood test that of BLV positive cattle, the number of WBC was slightly Increased, but other records were normal.

• 한국임상수의학회지
• /
• 제20권2호
• /
• pp.172-176
• /
• 2003

As a baseline study for the establishment of bovine leukemia virus(BLV)-free herd in Korea, the prevalence of anti-BLV antibody was determined in the present study. Sera from Korean native cows of 8 provinces and from dairy cattle of 9 provinces were subjected to enzyme-linked immunosorbent assay. Anti-BLV antibodies were positive in two (0.14%) of 1,413 Korean native cows. In contrast. 54.2% of 2,415 dairy cows were positive for anti-BLV antibodies, and their seropositive herd rate was 86.8%. And no differences were found in the sero-positive rates with age. The results indicate that the BLV infection rate has been increased continuously in Korea and that the establishment of BLV-free herd is imminent.

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

• 한국동물위생학회지
• /
• 제21권3호
• /
• pp.255-260
• /
• 1998

Since bovine leukosis caused considerable economic loss to the dairy industry, seroepidemiologi-cal survey on bovine leukosis was carried out for the dairy herds in Kyunggi province. 1. When compared the results of immunodifussion test with those of enzyme-linked immunosorbent assay(ELISA) for 94 dairy herds sera, the relationship between the immunodifussion test and ELISA were showen high corresponding rate with sensitivity(97.5%) and specificity(92.6%). 2. In immunodiffusion test for bovine leukosis virus (BLV) antibody in 570 dairy cattle from 30 herds, mean positive rate for BLV antibody was 28.2%. The positive rate by districts were 16.5% in central, 35.4% in east, 17.3% in west, 29.1% in south, 31.6% in north, 43.7% in northeast. 3. When the results of serological studies was analyzed by age groups, the number of positive was increased gradually with the advanced in age of herds. The highest positive rate was found in the age over 6 years. 4. Of 30 dairy herds examined, 5 herds(16.7%) have no reactions against BLV antigen while 15 herds (50%) showed the range of 1∼5 positive cattle and 5 herds(16.7%), the rang of over 11 positive cattle.

• 한국동물위생학회지
• /
• 제18권1호
• /
• pp.1-21
• /
• 1995

To elucidate pathogenesis of bovine leukemia virus(BLV) in Korean native goats, the goats experimentally infected with BLV were studied especially for the aspects of infectivity and hematological changes. The experimental goats were examined for 27 months by agar-gel immunodiffusion(AGID) test and syncytium formation assay. During this period, changes of total leucocyte, absolute Iymphocyte and atypical Iymphocyte were examined, and the distribution of surface immunoglobulin ( sIg ) -bearing cells and rosette forming cell (RFC) in the peripheral Iymphocyte were also investigated. By indirect immunofluorescence (IFA) and complement dependent antibody cytotoxicity (CDAC) assay using monoclonal antibody(Mab) against bovine leukosis tumor-associated anti-gen(BL-TAA), changes of BL-TAA positive Iymphocyte in peripheral blood were measured. The results obtained through the experiment were summarized as follows. 1. Antibody titers were measured by AGID using gP51 and P24 antigens. The animals were serologically converted at 2 months post-inoculation(pi) in gP51 antigen, whereas sero-converted at 4 months pi in P24 antigen. In comparison with antibody titers for gP51, P24 antigen showed lower titers throughout the trial period. 2. The peripheral lymphocytes from all of the infected goats, as co-cultivated with F8l cells manifested syncytial formation at 4 months pi. 3. On counting total leucocyte, Iymphocyte and atypical Iymphocyte, two out of four infected goats showed normal distribution, while No 2 of the remaining two revealed temporal and No 3, Persistant increasing number of the cells. 4. The optimal condition of rosette formation of the peripheral Iymphocyte of normal Korean native goats was shown in the sheep erythrocyte treated with 0.1M AET for 30 nun at $37^{\circ}C$. When the Iymphocytes were treated in nylon wool column, the number of sIg-bear-ing cell were increased in the nylon wool adherent cells, but RFC was increased in the non-adherent cells. Of the infected goats, No 2 and No 3 showed significantly increasing number of sIg-bearing cells at 18 months pi. 5. The Iymphocytes of No 2 and No 3 goats reacted positively in IFA using Mab against BL-TAA at 12 months pi and 18 months pi, respectively. In CDAC test, all of four infected goats revealed positive reaction at 24 months pi. The higher positive rates were observed in No 2 and No 3 as compared with the remainders.

• 대한수의학회지
• /
• 제55권1호
• /
• pp.53-56
• /
• 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.