Characteristics of Bovine Lymphoma Caused by Bovine Leukemia Virus Infection in Holstein-Friesian Dairy Cattle in Korea

Numerous studies have been made on the BLV and EBL in Korea (Son et al., 1968;Jun et al., 1982;Choi et al., 1992).Frthermore 54.2% in Holstein-Friesian dairy cattle was BLV-seropositive in recent report (Suh, 2004).However, few studies have been performed on lymphoma, the clinical form of EBL, until now (Lim, 1969;Lee et al., 1982), and the reports on characteristics of lymphoma in the naturally BLV-infected cattle are limited in Korea.It is the purpose of this study to assess the frequency and distribution of lymphoma in the BLV-infected cattle. MATERIALS AND METHODS AnimalsSamples were obtained from slaughtered cattle, and from cattle submitted for disease diagnosis to the Pathology division, National Veterinary Research Quarantine Service (NVRQS), Korea.Four lymphoma-suspected samples were collected at NVRQS diagnostic laboratory from January 1993 to June 2004 and 43 samples at abattoir from January 2002 to June 2004. Gross observation of lymphomaAll part of carcass and the organs in the abdominal and thoracic cavities were carefully observed for the presence of lymphoma-like nodular lesion.However, superficial lymph node, spinal cord, and head were not examined in many cases, because they were routinely removed and discarded after post-mortem inspection in abattoir.Ante-mortem inspection was also not done in all cases. Polymerase chain reaction (PCR) testNested PCR test was performed on all cattle with lymphoma-suspected gross lesion, as described earlier to detect env gene, coding for GP51 of BLV provirus (Ballagi-Pordany and Belak, 1996;Kobayashi et al., 2004; Renstrom et al., 2000).Table 1 shows the sequences of the primers for Characteristics of Bovine Lymphoma Caused by Bovine Leukemia Virus Infection in Holstein-Friesian Dairy Cattle in Korea