Development of loop-mediated isothermal amplification method for diagnosis of bovine leukemia virus infection

A rapid, sensitive loop-mediated isothermal amplification (LAMP) assay was established for diagnosis of bovine leukemia virus (BLV) infection. The LAMP assay for targeting the BLV-LTR region can detect at least 2 copies of proviral DNA in a 2 μl sample and its sensitivity is equivalent to or greater than the conventional single PCR. In addition, amplification is obtained in less than 1 h by incubating a single tube in a water bath. The data obtained by the LAMP assay applied to field samples were compared with PCR and serological tests for BLV. The results showed a high level of agreement with these serological methods, but there was one animal positive only by the LAMP assay. When the blood was collected from the cow after 6 months, the BLV antibody was detected. This suggested that the LAMP assay could help the detection of the cattle in the early stage of BLV infection. The LAMP assay is a rapid, sensitive and simple method for the diagnosis of BLV infection as reported for other pathogens, and is available for use in local laboratories without any special equipment.