Comparison of BLV detection by BLV-CoCoMo-qPCR, nested PCR, and serological tests. (A) BLV proviral load, as evaluated by BLV-CoCoMo-qPCR, in whole blood from 370 cattle that were either positive (+) or negative (−) for BLV LTR sequences, as determined by nested PCR, and serological tests such as the passive hemagglutination reaction (PHA), agar gel Immunodiffusion (AGID) and enzyme-linked immunosorbent assay (ELISA). Bars show the median BLV proviral load values. The actual number of cattle that were positive by BLV-CoCoMo-qPCR alone per number of cattle that were either positive (+) or negative (−) for BLV infection as determined by each test is indicated at the upper of each block. (B) Nested PCR positive rates for different proviral copy numbers per 105 cells (copy number of 0-105), as evaluated by BLV-CoCoMo-qPCR. The positive rate was 1.3 % when the proviral load was 0.