Comparison of neutralizing antibodies to type 1a, 1b and 2 bovine viral diarrhea virus from experimentally infected and vaccinated cattle

Abstract

Serum neutralizing (SN) antibody titres to cytopathic (cp) type 1a, type 1b and type 2 bovine viral diarrhoea viruses (BVDV) were determined for yearling, crossbred beef heifers immunized with a modified live cytopathic type 1a BVDV vaccine, or experimentally infected with a noncytopathic (ncp) type 1b or a ncp type 2 BVDV. The results indicate that type-specific and cross-reactive SN titres are usually found to all three test viruses in an individual animal, with the highest SN titres to the same genotype of BVDV as the challenge or vaccine virus. Exceptions to this trend were found in individual animals, however, emphasizing the importance of comparing the SN titres for several animals in a herd. Determining SN titres to the three BVDV genotypes may help veterinarians distinguish the BVDV genotype involved in a herd infection from antibody titres due to vaccination.