Abstract: The invention disclosed herein presents an antigen-capture immunoassay that utilizes serum, plasma, milk, urine, saliva, or other bodily fluid samples to identify cattle infected with the Bovine Viral Diarrhea Virus (BVDV). The results of this assay allow an effective, reliable, quick, and cost efficient way to identify, and thereby remove, infected cattle and/or other ruminants from otherwise uninfected herds. The BVD virus causes an acute enteric disease with a variety of clinical manifestations, and is closely related to sheep border disease virus (BDV) and hog cholera virus (HCV). The traditional method of detecting infected animals, including persistently infected (PI) carriers, has been through the use of virus isolation procedures. While this older test methodology can detect infected animals, the virus isolation test can only be performed by highly trained technicians in a highly specialized laboratory facility.