An experimental inactivated, oil assisted Aujeszky's disease virus vaccine was tested for its ability to induce immunity, clinical protection level and reduction of viral infection after challenge by the nasal route. Groups of 6 pigs, 45 days-old, were vaccinated once or twice, by either intramuscular or subcutaneous routes. A group of unvaccinated animals was used as control. All the vaccinated pigs developed neutralizing antibodies, detected by serum-neutralization test. In pigs vaccinated twice the levels of neutralizing antibodies were higher than in pigs vaccinated once, and this difference was statistically significant. In vaccinated animals, the severity of clinical signs decreased with increasing antibodies titres. Aujeszky's disease virus was detected in tonsils of vaccinated and unvaccinated pigs by immunofluorescence method. However, the rate of positive tonsils in pigs vaccinated twice was reduced when compared with unvaccinated pigs on the 2nd and 7th days post-infection. The level of infection was statistically reduced in twice vaccinated pigs by subcutaneous route as compared with vaccinated once and unvaccinated animals.
Aujeszky's disease; Inactivated vaccines; Tonsils
