|Cortese, V - PFIZER ANIMAL HEALTH|
|Whittaker, R - WHITE ACRE RGSTRD ANGUS|
|Ellis, J - UNIV OF SASKATCHEWAN|
Submitted to: American Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 13, 1998
Publication Date: N/A
Interpretive Summary: Bovine viral diarrhea virus (BVDV) is a widespread viral pathogen of cattle that causes respiratory, reproductive, and enteric disease. Both inactivated virus and modified-live virus vaccine have been developed against BVDV. Inactivated virus vaccines have been shown to induce viral neutralizing antibody that is protective, but the duration of antibody in the blood of cattle is limited to about 6 months. A modified-live virus vaccine was administered to cattle and the viral neutralizing antibody that was induced by the vaccine was tested against a broad antigenic array of viruses at periodic intervals through 18 months after vaccination. The vaccine stimulated production of viral neutralizing antibody that was reactive against 12 antigenically different viruses from 1 month after vaccination through 18 months after vaccination. Thus, it was shown that duration of antibody in blood of cattle was extended by administration of modified-live virus vaccine. This finding indicates that a yearly vaccination of cattle using a modified-live virus vaccine should maintain blood levels of antibody that can neutralize a broad antigenic array of BVDV. This knowledge will benefit veterinarians and cattle producers in formulating protection strategies against BVDV.
Technical Abstract: The objective was to determine the duration for cross-neutralizing antibodies stimulated by administration of a single dose of modified- live vaccine against bovine viral diarrhea virus (BVDV) to seronegative cattle. Cows were randomly assigned to control (unvaccinated) or test (vaccinated) groups. Eighteen BVDV- seronegative Angus cattle were vaccinated via IM injection with a modified-live BVDV (NADL strain) vaccine and commingled with 5 unvaccinated seronegative cows. Serum was obtained from the cows before vaccination, on the day of vaccination, and 1.5, 3, 6, 9, 12, and 18 months after vaccination. Serum neutralizing antibody tests were performed on samples obtained at each point after vaccination, using a panel of 12 strains of BVDV that, on the basis of reactivity with monoclonal antibodies, were identified as heterologous. Antibodies against all 12 strains of BVDV were detected by use of viral neutralization testing in samples obtained from vaccinated cattle 18 months after vaccination; however, concentration of antibody for some of the strains was low. Nonvaccinated cattle remained seronegative throughout the 18-month study period. Analysis of these data indicated that modified-live BVDV vaccines could stimulate an antibody response in seronegative cows that was detectable for at least 18 months after vaccination. These antibodies were able to cross neutralize 12 antigenically diverse strains of BVDV.