Comparison of three polymerase chain reaction methods for routine detection of bovine herpesvirus 1 DNA in fresh bull semen

Five bulls were inoculated intrapreputially with Bovineherpes virus 1 (BHV 1), in order to compare the relative sensitivity of three polymerase chain reaction (PCR) assays for routine diagnosis of fresh bovine semen for the p resence of BHV 1 Semen was collected twice a week up to 107 days post-infec tion (dpi). To reactivate latent virus, the bulls were treated with dexamet hasone from 44 until 48 dpi. All samples were examined before and after cry opreservation treatment using a standard virus isolation (VI) method and th ree PCR assays: PCR A, PCR B and PCR C. PCR A and PCR C used an internal co ntrol plasmid DNA template and PCR B used the split sample method in order to control for false negative results. Of the 149 fresh semen samples that were tested, PCR A detected 45 positive, PCR B detected 39 positive and PCR C detected 66 positive, while virus was isolated from 22 samples. Of the 1 49 samples treated by cryopreservation, the virus was isolated from 13 samp les and PCR C was positive in 21 samples. The results demonstrate that all three PCR assays are more sensitive than virus isolation, particularly duri ng the later phases of infection. (C) 2000 Elsevier Science B.V. All rights reserved.