Sl. Swenson et al., EVALUATION OF THE SAFETY AND EFFICACY OF A THYMIDINE KINASE, INVERTEDREPEAT, GI, AND GPX GENE-DELETED PSEUDORABIES VACCINE, Journal of veterinary diagnostic investigation, 5(3), 1993, pp. 341-346
A thymidine kinase (TK), inverted repeat, glycoprotein I (gI) and glyc
oprotein X (gpX) gene-deleted modified live virus pseudorabies vaccine
was evaluated for safety in swine and for efficacy in protecting swin
e against challenge with pseudorabies virus (PRV). Safety was evaluate
d by inoculating pregnant gilts intravenously and 3-day-old pigs intra
cerebrally with the vaccine. Efficacy was evaluated by 1) vaccinating
3-day-old pigs with a minimal protective dose intranasally and then ch
allenging with PRV 3 weeks postvaccination or 2) vaccinating weaned pi
gs with a standard field dose intramuscularly and then challenging wit
h PRV 4 weeks postvaccination. The pigs vaccinated intranasally remain
ed clinically normal following vaccination and challenge with PRV. The
pigs vaccinated intramuscularly remained clinically normal following
vaccination, but mild respiratory sips were seen in some of the vaccin
ated pigs following challenge with PRV. Humoral immune response was ev
aluated with enzyme-linked immunosorbent assays (ELISAs) and a serum v
irus neutralization test. All of the intramuscularly vaccinated pigs b
ecame gI and gpX positive on differential ELISAs following challenge.
All of the intranasally vaccinated pigs were seropositive on the indir
ect gI ELISA following challenge, but not all of the pigs were seropos
itive on the blocking gI ELISA or the gpX ELISA 3 weeks postchallenge.