Experimental vaccination of rabbits with non-pathogenic strains of Aujeszky's disease virus.

1. The Bartha K and NIA-4 strains of Aujeszky's disease virus (ADV) were non-pathogenic for rabbits vaccinated once or twice by nasal instillation or intramuscular injection. Neutralizing antibodies were detected in 68% of the rabbits two weeks after primary vaccination and in all rabbits at challenge. 2. Challenge doses of virulent ADV greater than 10(5.0) median tissue culture infective doses (TCID50) resulted in the death of most vaccinated and all unvaccinated rabbits with typical signs of Aujeszky's disease within 4 days. ADV was recovered from brain and lung suspensions of vaccinated and unvaccinated rabbits who had died as a result of the challenge. 3. When the challenge dose was reduced to approximately 10(3.0) TCID50, rabbits vaccinated twice survived while all unvaccinated controls died within 3 days.