Patent ID: 7754222

Claim:
A vaccine comprising at least two live mutant viruses, wherein said viruses comprise a mutant cytopathic (cp) Bovine Viral Diarrhea Virus Type 1 (cp BVDV-1) and a mutant cytopathic Bovine Viral Diarrhea Virus Type 2 (cp BVDV-2), wherein the cp BVDV-1 and the cp BVDV-2 each contains a mutation in the viral genome that resides in the same genomic site such that said cp BVDV-1 and said cp BVDV-2 cannot recombine with each other to eliminate the mutations, and further wherein said cp BVDV-1 and cp BVDV-2 are both attenuated.