Protection of pregnant cattle and their fetuses against infection with bovine viral diarrhea virus type 1 by use of a modified-live virus vaccine.
OBJECTIVE
To determine efficacy of a vaccine containing modified-live bovine viral diarrhea virus (BVDV) type 1 for protecting pregnant cows and their fetuses against virulent heterologous BVDV type 1.


METHODS
Randomized controlled cohort study.


METHODS
18 yearling beef heifers seronegative for BVDV and negative when tested for BVDV by virus isolation.


METHODS
Cattle were randomly assigned to control (unvaccinated; n = 6) or vaccinated (12) groups. Vaccinated heifers were given a combination vaccine containing modified-live BVDV type 1 comprising a cytopathic (NADL) strain. All 18 heifers were then bred and challenge-exposed between 70 and 75 days of gestation with BVDV type 1, administered intranasally. Cattle were monitored, and infection status of offspring was determined after parturition. Antibody concentrations of vaccinated and control heifers were also monitored.


RESULTS
All 6 calves from control heifers had positive results on multiple virus isolation tests and were considered persistently infected. In comparison, only 2 calves from vaccinated cows had positive results on virus isolation tests and were considered persistently infected. One vaccinated heifer aborted, but the fetus was not persistently infected, and the abortion was not attributed to BVDV infection.


CONCLUSIONS
Analysis of these data indicated that a single dose of a modified-live NADL-derived BVDV type 1 vaccine will confer protection to dams and their fetuses against challenge-exposure to heterologous BVDV type 1 organisms.
Cortese
V S
VS
Pfizer Animal Health Inc, Exton, PA 19343, USA.
Grooms
D L
DL
Ellis
J
J
Bolin
S R
SR
Ridpath
J F
JF
Brock
K V
KV
D000818:Animals; D001483:Base Sequence; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000517:prevention & control* / Q000635:transmission; D002417:Cattle; D015331:Cohort Studies; D004279:DNA, Viral / Q000737:chemistry; D030241:Diarrhea Virus 1, Bovine Viral / Q000276:immunology*; D005260:Female; D005315:Fetal Diseases / Q000517:prevention & control; D018445:Infectious Disease Transmission, Vertical; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000517:prevention & control / Q000662:veterinary*; D011270:Pregnancy, Animal / Q000276:immunology*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014611:Vaccination / Q000662:veterinary; D017778:Vaccines, Combined / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology
D004279:DNA, Viral; D017778:Vaccines, Combined; D014765:Viral Vaccines