• Journal of Veterinary Clinics
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• v.27 no.4
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• pp.402-406
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• 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.

• Journal of the korean veterinary medical association
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• v.33 no.4
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• pp.239-244
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• 1997

• Korean Journal of Veterinary Service
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• v.32 no.2
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• pp.111-117
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• 2009

Farmed deer could be susceptible carrier to bovine viral infectious disease. But unfortunately, there has not been an overall study over this subject in Korea so far. Therefore, a study was conducted to see serum antibodies to bovine leukosis, food and mouth disease, bovine viral diarrhea and infectious bovine rhinotracheitis in deer using the sera of farmed deer. As a result, two deer in a farms showed positive in bovine leukosis antibodies, using ELISA. For wild water deer, no antibodies were found for those diseases. As a result, it can be assumed that deer were relatively low rate of exposure to highly contagious disease such as viral bovine infectious disease in Korea. As this study was conducted over limited in number of subject and regions, continued study should be carried out in order to prevent and control the interspecies transmission in the future.

• Korean Journal of Veterinary Service
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• v.35 no.2
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• pp.139-145
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• 2012

Prevalence of major legal communicable diseases in bovine and swine had been monitored in Jeonbuk province from year 2004 to 2008. At least 1 communicable disease had been reported in 687 heads from 68 bovine farms and 17 farms (25.0%) of the 68 positive farms had 1~2 additional outbreaks during the surveillance. By disease, enzootic bovine leukosis, Johne's disease and Akabane disease were occurred in 53 farms (582 heads), 14 farms (100 heads) and 1 farm (5 heads), respectively. Swine communicable diseases were occurred in 4,466 heads from 63 swine farms and 18 farms (28.6%) of the 63 positive farms had 1~2 additional outbreaks during the surveillance. By disease, Aujeszky's disease (AD), porcine epidemic diarrhea (PED), classical swine fever (CSF), porcine reproductive and respiratory syndrome (PRRS), porcine transmissible gastroenteritis (TGE), atrophic rhinitis (AR) and Japanese encephalitis in swine (JE) were occurred in 20 farms (70 heads), 20 farms (2,817 heads), 12 farms (258 heads), 6 farms (1,257 heads), 1 farm (50 heads), 1 farm (2 heads) and 1 farm (10 heads), respectively. In total, 10 communicable diseases (1 species of first-class, 3 species of second-class, and 6 species of third-class) were reported. The first-class diseases were CSF. Johne's disease, and Aujeszky's disease. JE was the second-class and Akabane disease, enzootic bovine leukosis (EBL), PED, PRRS, TGE and AR were third-class diseases.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2004.10a
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• pp.45-45
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• 2004

• Korean Journal of Veterinary Research
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• v.8 no.1
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• pp.31-38
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• 1968

Hematological surveys using Bendixen's and Goetze's Key for bovine lymphosarcoma were made in dairy herds which have been composed of the cows imported from United States, Canada and Japan, and their calves in the area of Taegu and Chung-Nam. The results obtained were summarized as follows: 1. Of 521 cattle, 15(2.9%) were hematologically positive for lymphosarcoma; 28(5.4%) were suspect with Bendixen's Key, and 7 (1.3%) were positive; 26(5.%) were suspect with Goetze's Key. 2. Of 14 herds, 5 were involved in positive or suspect for lymphosarcoma with Bendixen's and Goetze's Key more than 5 per cent. Of the above 5 herds, 3 were involved in positive or suspect more than 30 per cent. These findings suggest that repeated hematological examinations and continuous clinical observations are required in the herds showed higher level of per cent of positive or suspect.

• Korean Journal of Veterinary Research
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• v.55 no.1
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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.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.6
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• pp.879-883
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• 2005

The integral relationship between the occurrence of lymphocyte nuclear pockets (LNPs) and BLV-infection was examined in Holstein-Friesian dairy cattle in Korea. Transmission electron microscope (TEM) was used to detect LNP in peripheral blood lymphocytes. Morphologically, the membranes of LNP were composed of two layers of double nuclear membrane. The full thickness of LNP membranes including inner and outer nuclear membrane was 60 to 70 nm. LNP prevalence was different according to the bovine leukemia virus (BLV) infection status; in BLV-seropositive cattle, LNP prevalence was 48.4% and in BLV-seronegative cattle prevalence was 5.9%. Moreover, even in seropositive animals, leukemic group was the highest at 70% positive among the groups, followed by suspect group (42.4%) and aleukemic group (23.1%). Consequently, the numbers of LNP were increased in proportion to increase of the numbers of leukocytes among BLV-seropositive cattle. The numbers of LNP per lymphocyte were increased in BLVseropositive cattle compared with seronegative cattle. The mean numbers of LNP per 100-lymphocytes were 0.35, 0.77, 1.64 and 4.7 in BLV-seronegative, BLV-seropositive aleukemic, suspect and leukemic groups, respectively. Thus, it is reasonable that LNP test can be used as the one of the diagnostic criteria of BLV infection.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2005.11a
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• pp.64-64
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• 2005

• Journal of Veterinary Clinics
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• v.2 no.1
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• pp.79-104
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• 1985

Clinical and cytomorphological studies were carried out in 32 leukotic cattle from Tokachi and Kushiro districts in Hokkaido during the 12 year period from 1969 to 1980. The leukotic cattle were examined :and divided into four types(15 cases of the adult, 11 cases of the thymic, 4 casas of the calf and 2 cases of the skin types). The results obtained were as follows : 1. As for the frequency of the main clinical signs in each type, In the adult type, the main clinical signs (of decreasing order) are as follows: swelling of the superficial lymph nodes>depression and loss of weight>tachycardia>anorekia, anemia of the visible mucous membrane and tachypnea. Those of the thymic type were swelling of the thymus>swelling of the medial iliac lymph nodes> swelling of the superficial lymph nodes>tachypnea. Those of the calf type were swelling of the auperficial lymph nodes>depression and emaciation>tachypnea>anorexia, tachycardia, anemia of the visible mucous membrane and recumbency. Those of the skin type were generalized urticaria-like lesions in skin and swelling of superficial lymph nodes>and depression and loss of weight in the decreasing order of frequency. In addition, large tumor mass in the pelvic cavity and swelling of the medial iliac lymph nodes were detected through rectal palpation in 33.3% and 100% in the adult type cases, respectively. 2. As for the hematological findings, The frequency of occurrence of decreased erythrocyte counts in the decreasing order were as follows : adult>calf>thymic>and skin types. The increase in the total leukocyte count in the order of decreasing frequency were as follows: calf>thymic>adult>and skin types. The increase in the absolute lymphocyte counts was found to be at a low rate, 62.5% of all the cases examined. By contrast, the increase of 5% or more of abnormal lymphocyte rates was observed at a high rate, 96.9% of the total cases. 3. Abnormal lymphocytes were found in all cases examined for lymph nodes biopsied. 4. From the cytomorphological point of view, leukotic cells were divided into 3 types: reticulum cell, lymphoid cell and monocytic cell types. The adult type leukotic cattle were divided with reticulum cell type (66.7%), the lymphoid cell type(22.6%) and monocytic cell type(6.7%). The thymic type was lymphoip cell type(72.7%) and reticulum cell type(27.3%). In the calf type, all were lymphoid cell type while all of the skin type were reticulum cell type only. 5. The leukotic cattle had higher NP frequency in the blood and lymphoid tissue than non-1 eukotic cattle. Especially the adult type had the highest NP frequency. However, it was not recognized that NP were characteristic of leukotic cattle alone. 6. The above findings lead to the conclusion that the most effective diagnostic methods for bovine leukosis are the confirmation of swelling of the superficial and internal lymph nodes and thymus in addition to appearance of abnormal neoplastic cell in the peripheral blood and lymph nodes biopsied.