LABORATORY DIAGNOSTIC-TESTS FOR RETROVIRAL INFECTIONS IN DAIRY AND BEEF-CATTLE

Detection of bovine retroviruses stretches our diagnostic creativity t o its Limits. The nucleic acid-based, PCR-amplified assays are finding increased clinical use as the veterinary and livestock industry seek earlier detection of infection for eventual corrective management deci sions. We are evolving from a point of disease diagnosis by tumor iden tification through conventional histopathology, to molecular diagnosti cs for early identification of retroviral nucleic acid (provirus). The clinical use of antibody-based assays lies in the simplicity of testi ng large numbers of animals, the relative sensitivity of the assays, a nd the low cost of testing. Although the pathogenicity of bovine leuke mia virus (BLV) for cattle has been well documented, the disease poten tial for bovine immunodeficiency-like virus (BIV) for cattle is still being determined. Nevertheless, pressure to test for retroviral infect ions of livestock and, when feasible, removal of these infected animal s from the herd will be increased.