[Effect of passive immunity on subsequent vaccination against swine fever]

Studied was the effect of a serum paratyph and Aujeszky gammaglobulin injected 10, 15, and 20 days prior to the crystal-violet and the lapinized vaccine. If the animals were infected with a pathogenic swine fever virus 10 to 15 days after their treatment with serum at the rate of 0.5 cu. cm per kg, part of them died, and the remaining contracted the disease showing a protracted course. The control vaccination on the 20th day after the animals were injected with serum led to the death of all of them showing the signs of acute swine fever. Most of the pigs injected with 5 cu. cm gamma-globulin each and 10--15 days later being infected with a swine fever virus manifested the disease, however, none of them died of the disease. If, however, after treatment with gamma-globulin they were challenged on the 20th day all of them died of acute swine fever. In the immunization of pigs with a crystal-violet vaccine on the 14th day of their treatment with Aujeszky gamma-globulin, part of them developed an atypical form of the disease, while most of them did not show symptoms whatever of swine fever. Of the immunized with a lapinized vaccine some died, and the remaining part did not contract the disease at all. All this pointed to the fact that the residual antibodies against swine fever contained in the specific Aujeszky gamma-globulin could still be in a position to inhibit the vaccinal virus, and more specifically that of the lapinized K vaccine. The vaccination against swine fever should be performed 14 days after the injection of the serum paratyph and about 20 days after the injection of the Aujeszky gammaglobulin.