Response of growth agglutinating antibody and protection of pigs inoculated with swine erysipelas live vaccine.

Abstract

Twenty-nine pigs were inoculated subcutaneously with live vaccine preparedfrom the acriflavine-fast attenuated Koganei strain of Erysipelothrix rhusiopathiae. All ofthem survived against intradermal challenge with virulent culture 1 /2, 1, 2, 3 or 4 monthsfollowing vaccination. Five unvaccinated control pigs died after challenge, except onewhich showed severe clinical symptoms. In the vaccinated pigs, the growth agglutination(GA) titer in the serum began to rise on the 5th day after vaccination and reached amaximum on the 10th or 15th day. Then it dropped gradually up to 40 days after vac-cination. After that, it remained at almost the same level. It did not rise significantly bychallenge made within 2 months after vaccination, but rose clearly by challenge made 3 or4 months after vaccination, regardless of GA titer before challenge and manifestation ofa local skin reaction at the site of challenge inoculation. There was a good correlationbetween the highest GA Liter in the serum of each pig in the early stage after vaccinationand the intensity of skin reaction in the pig to challenge made in various stages aftervaccination. Therefore, it was concluded that the highest GA titer in the early stage aftervaccination might indicate the duration of immunity in pigs. Vaccinated pigs having a GALiter of 8 or below before challenge exhibited some distinct clinical reaction to challenge.Vaccinated pigs having a GA titer of 16 were resistant to challenge, with no or some reac-tion. On the other hand, vaccinated pigs having a GA titer of 32 or above presented noclinical reaction to challenge.