Safety aspects in the development of an infectious bovine rhinotracheitis marker vaccine.
Clinical trials in cattle demonstrated that the IBR marker modified live vaccine based on the gE-deleted IBR strain Difivac is immunogenic and safe for bovines of all ages. Potential effects of the vaccine virus have also been tested in swine and sheep and proved safe for these species as well. For evaluation of other environmental aspects, the spread of the vaccine virus after immunisation was investigated. The data indicated that the vaccine virus may be shed by immunised animals but that it has a limited ability to pass from animal to animal. It was also demonstrated that the attenuated Difivac strain does not revert to virulence during calf passage. Preliminary results indicated that the gE-deleted vaccine virus of the IBR marker vaccine cannot be reactivated after dexamethasone treatment, an important advantage for a vaccine strain. Furthermore, immunisation with the Difivac strain reduced the ability of a superinfecting challenge virus to become latent or to be reactivated.
Strube
W
W
Bayer AG, Institute of Infectious Diseases, Leverkusen, Germany.
Abar
B
B
Bergle
R D
RD
Block
W
W
Heinen
E
E
Kretzdorn
D
D
Rodenbach
C
C
Schmeer
N
N
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control; D004783:Environmental Microbiology; D005260:Female; D005819:Genetic Markers; D006566:Herpesviridae Infections / Q000517:prevention & control / Q000662:veterinary; D007242:Herpesvirus 1, Bovine / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D008297:Male; D011247:Pregnancy; D012449:Safety; D014611:Vaccination / Q000662:veterinary; D014613:Vaccines, Attenuated / Q000009:adverse effects / Q000302:isolation & purification / Q000592:standards; D014614:Vaccines, Synthetic / Q000009:adverse effects / Q000302:isolation & purification / Q000592:standards; D014765:Viral Vaccines / Q000009:adverse effects / Q000302:isolation & purification / Q000592:standards*; D014774:Virulence / Q000235:genetics
D005819:Genetic Markers; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D014765:Viral Vaccines