Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). We used microchip electrophoresis in combination with automatic image analysis to develop a novel high-throughput PCR–RFLP to type the gene sequences that encode BLV Tax 233. This method revealed that 233L-Tax is more prevalent than 233P-Tax in cattle in Japan. The proportion infected with BLV carrying the gene encoding 233L-Tax was significantly higher in Holstein cattle than in Japanese Black cattle. Holsteins infected with BLV encoding 233L-Tax had higher proviral loads than did Holsteins infected with BLV encoding 233P-Tax and Japanese Blacks infected with BLV encoding 233L-Tax or 233P-Tax. The novel method developed in this study will be a useful tool for identifying cattle harboring BLV with a higher risk of EBL and viral transmission.

牛白血病病毒（BLV）是致病性牛白血病（EBL）的病原体。我们将微芯片电泳技术与自动图像分析结合使用，开发出了一种新型的高通量PCR-RFLP，可用于编码BLV Tax 233的基因序列。这种方法揭示了在日本牛中233L-Tax比233P-Tax更为普遍。在荷斯坦牛中，携带带有233L-Tax编码基因的BLV感染的比例明显高于日本黑牛。感染了BLV编码233L-Tax的荷斯坦犬的原病毒载量高于感染了BLV编码233P-Tax的荷斯坦犬和感染了BLV编码233L-Tax或233P-Tax的日本黑人。在这项研究中开发的新方法将是一种有用的工具，以鉴定带有EBL和病毒传播较高风险的BLV牛。