Rectal temperatures of normal rabbits inoculated with different dilutions of a vaccine prepared with Chinese-Porto Alegre (CPA) strain of classical swine fever virus, were evaluated under 3 different environmental temperatures. Temperatures of normal un-vaccinated rabbits increased significantly when environmental temperature increased (P<0.001). At environmental temperatures of 12.82 ± 1.29°C, 20.65 ± 1.79°C, and 28.24 ± 2.09°C me mean rectal temperatures were 39.53°C, 39.65°C and 39.92°C, respectively. Temperatures of me vaccinated rabbits also increased significantly when environmental temperature increased (P<0.001), but did not vary with different vaccine dilutions. At environmental temperatures of 12.82 ± 1.29°C, 20.65 ±1.79°C and 28.24 ± 2.09°C, the mean higher rectal temperature were 41.17°C, 41.24°C and 41.47°C, respectively. Within a 95% confidence interval was determined that, under the 3 environmental temperatures, the rectal temperatures equal to 40.60°C, 40.67°C and 40.90°C or higher, indicated a thermal reaction to the vaccine. In vaccinated rabbits, the mean thermic rise was of 1.59°C and there were no significant differences at different environmental temperatures or virus dilutions. Within a 95% confidence interval was determined that a rise of 1.06°C or higher indicated a specific reaction to the vaccine. The rise in temperature started 24 hours after the inoculation. This time was delayed when virus dilutions decreased (P<0.001), but did not vary with different environmental temperatures. The sensitivity and specificity of the thermic reaction was evaluated by the challenge test. By regression analysis was concluded that a temperature of 40.6°C, associated with a rise in at least 1.06°C, could be considered a specific reaction of the rabbits to the CPA strain.
Classical swine fever; vaccine; CPA; rabbit
