Seroepizootiological Study on Bovine Leucosis in Korea

Jun, Moo-Hyung; Chung, Un-Ik; Lee, Chang-Ku; Baig, Soon-Yong; Lim, Chang-Hyeong

Korean Journal of Veterinary Research 1982;22(2):175-185.

Moo-Hyung Jun¹, Un-Ik Chung¹, Chang-Ku Lee¹, Soon-Yong Baig², Chang-Hyeong Lim³

¹Institute of Veterinary Research, Office of Rural Development
²Livestock Experiment Station, Office of Rural Development
³College of Veterinary Medicine, Seoul National University

한국(韓國)에서의 소백혈병(白血病)의 혈청역학적(血淸疫學的) 연구(硏究)

전무형¹, 정운익¹, 이창구¹, 백순용², 임창형³

¹농촌진흥청 가축위생연구소
²농촌진흥청 축산시험장
³서울대학교 수의과대학

Abstract

Since bovine lymphosarcoma causes considerable economic loss to the dairy industry, seroepidemiological survey on bovine leucosis virus (BLV) was carried out for the dairy herds throughout the country to observe the epidemiological situation of the disease by using immunodiffusion test. Attempts were simultaneously made to detect bovine leucosis virus in the lymphocytes from BLV antibody-positive cattle by means of fluorescent antibody techniques, syncytium assay and electron microscopy. In immunodiffusion test for BLV antibody in 2003 heads of dairy cattle selected randomly from 164 herds, the prevalence of positive reactors by regions were 37.8% in Central, 27.2% in Honam (Southwest), 28.0% in Youngnam (Southeast) and 25.2% in Youngdong (East coast)and averaging 29.7%. By provinces, Chungcheong appeared the highest prevalence of BLV antibody carriers (41.8%), while Jeonbug revealed the lowest incidence rate (24.4%). When the results of serological studies were analyzed by age groups and the sizes of herds, the number of reactors increased gradually with the advance in the age of cattle and the herd size. The highest rate of BLV carriers was found in the ages between 6 and 8 years, and in the size of herds with 20 to 50 heads. One hundred and seventeen breeding bulls from the central regions were tested for BLV antibody. Four out of 70 bulls (5.7%) of Korean cattle and 14 out of 39 bulls (35.9%) of Holstein were reactive for BLV antigens. Of 164 dairy herds examined, 17 herds (10.4%) have no BLV antibody-positive cattle, while 42 herds (25.6%) were included in the range of 20 to 40% of the positive rate and 10 herds (6.1%) in the range of over 80% of the rate. When the lymphocytes from the BLV antibody carrying cattle were cultured in the presence of phytohemagglutinin and stained with FITC-conjugated sheep anti-BLV serum, 8 out of 11 cases (72.7%) of BLV positive cattle revealed specific fluorescence for BLV in the lymphocytes. In syncytium assay of the peripheral lymphocytes of the cattle, 5 out of 7 (71.4%) lymphocytes from BLV antibody carriers induced syncytia in the indicators of bovine embryonic splenic cells. The cultured lymphocytes were examined with an electron microscope to detect the BLV particles. Two out of 6 specimens (33.3%) from the reactors showed the typical type C virus with the size of 90 to 110 nm around microvilli and in intracytoplasmic vacuoles.