Bovine Viral Diarrhea Virus In Herds Research Articles

Development of an APC-targeted multivalent E2-based vaccine against Bovine Viral Diarrhea Virus types 1 and 2

The aim of this study was to develop and test a multivalent subunit vaccine against Bovine Viral Diarrhea Virus (BVDV) based on the E2 virus glycoprotein belonging to genotypes 1a, 1b and 2a, immunopotentiated by targeting these antigens to antigen-presenting cells. The E2 antigens were expressed in insect cells by a baculovirus vector as fusion proteins with a single chain antibody, named APCH I, which recognizes the β-chain of the MHC Class II antigen. The three chimeric proteins were evaluated for their immunogenicity in a guinea pig model as well as in colostrum-deprived calves. Once the immune response in experimentally vaccinated calves was evaluated, immunized animals were challenged with type 1b or type 2b BVDV in order to study the protection conferred by the experimental vaccine.The recombinant APCH I-tE21a-1b-2a vaccine was immunogenic both in guinea pigs and calves, inducing neutralizing antibodies. After BVDV type 1b and type 2 challenge of vaccinated calves in a proof of concept, the type 1b virus could not be isolated in any animal; meanwhile it was detected in all challenged non-vaccinated control animals. However, the type 2 BVDV was isolated to a lesser extent compared to unvaccinated animals challenged with type 2 BVDV. Clinical signs associated to BVDV, hyperthermia and leukopenia were reduced with respect to controls in all vaccinated calves. Given these results, this multivalent vaccine holds promise for a safe and effective tool to control BVDV in herds.

BVDV Management

Bovine viral diarrhea virus (BVDV) control programs should include identification and removal of the BVDV persistently infected (PI) animal, biosecurity, biocontainment and surveillance. Surveillance of BVDV in herds previously identified as having persistently infected animals and for herds of unknown BVDV status are the focus of this discussion. Issues discussed are considerations for tests used in BVDV surveillance programs, population for surveillance and timing of testing.

Persistent Infection and Sub-Clinical Bovine Viral Diarrhea Virus Transmission in Dairy Calves

Clinical disease associated with Bovine Viral Diarrhea Virus (BVDV) has been well documented in the literature and includes respiratory, enteric, hemorrhagic, and reproductive problems. While sub-clinical presence of BVDV in herds is also acknowledged, its significance and impact on animal health and herd economics are not well understood. The objective of our ongoing study is to understand BVDV transmission and how the virus becomes established at a sub-clinical level in typically managed herds. In the first phase of the project, reported here, we focused on identifying sources and extent of BVDV transmission in dairy herds.