• 종축개량
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• v.12 no.1 s.71
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• pp.112-114
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• 2007

• KOREAN POULTRY JOURNAL
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• v.6 no.6 s.56
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• pp.116-119
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• 1974

• Korean Journal of Veterinary Research
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• v.30 no.3
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• pp.343-348
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• 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.

• Korean Journal of Veterinary Service
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• v.30 no.1
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• pp.67-75
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• 2007

Bovine leukosis is one of the important diseases in Korea because of economic losses, and this study was conducted to provide basic information for the control of the disease. A total of 2,104 sera were obtained from 491 farms and examined by commercial kit. In the seroprevalence of farms and heads, 71 farms out of 491 were seropositive (14.5%) and 119 heads were positive (5.7%) out of 2,104. In the areal distribution of seropositiveness, Soseong-myeon showed the highest rate (39.5%, 15/38 farms)and Yeongwon-myeon was the lowest (2.6%, 1/38 farms). By age, positive rate in the below of 1 year old cattle was much less than that in the over of 1 year old, namely, the former was 1.9% (3/161 farms) and the latter 20.6% (68/330 farms). According to the farm size, there was no significant difference among the size. However, the highest rate was shown in the farms having 50-99 heads, 23.2% (13/56 farms).

• 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

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.50-50
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• 2003

Enzootic bovine leukosis(EBL) is chronic disease caused by bovine leukemia virus(BLV), retroviridae. The characteristic feature of this disease is proliferation of lymphocytes in circulating blood or lymphoid tissues. Because EBL concern lymphocytes, immunological disorder or alteration in the lymphocyte subpopulation is suggested. In this study, we investigated the changes of the lymphocyte subpopulation in the circulating blood of Korean native cattle infected with bovine leukemia virus. (omitted)

• Korean Journal of Veterinary Service
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• v.30 no.1
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• pp.95-102
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• 2007

The purpose of this study was to investigate the seroprevalence of infection with the production-limiting diseases in dairy cattle in Jeonbuk-Iksan area. The blood samples were collected from 260 dairy cows in 52 herds, and examined. The antibody rates against N caninum, M paratuberculosis, and bovine leukemia virus were 34.6%, 13.5% and 89.6%, respectively. All samples for bovine brucellosis were negative.

• 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.

• 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 Poultry Science
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• v.49 no.2
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• pp.99-108
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• 2022

Avian leukosis virus (ALV) is a highly contagious retrovirus that causes tumors and has resulted in great economic loss worldwide owing to its high transmission rate. Various ALV viral subgroups exist, with infections occurring via specific host receptors. The susceptibility or resistance of avian species to the ALV-A and K subgroups is determined by the host receptor, the tumor virus locus A (tva) gene, while that to ALV-B depends on another host receptor, the tumor virus locus B (tvb) gene. The resistance alleles of tva and tvb have primarily been identified in China, but none have beendetected in Korea. We analyzed the frequencies of tva and tvb genotypes in White Leghorn (WL), Korean Ogye (KO), and Korean native chicken (KNC) breeds, and assessed the resistance to ALV subgroups. In WL, both tva and tvb had various genotypes, including susceptibility and resistance alleles, whereas in KO, tva and tvb resistance alleles were dominant. In KNC, tva susceptibility and resistance alleles were mixed, whereas tvb resistance alleles were dominant. In addition, we showed that there were differences in the splicing pattern of tva transcripts and the expression level of tvb transcripts within breeds. Finally, we confirmed that ALV resistance depended on KO and KNC genotypes by in vitro infection of chicken embryonic fibroblasts with ALV. These results highlight that some KO and KNC individuals are naturally resistant to ALV subgroups A, B, and K, and will facilitate the preservation of economically superior traits through selective breeding.