[Localization and persistence of strain K in swine vaccinated against plague]

Pigs vaccinated with the lapinized K strain were studied by the immunofluorescence method, through bioassay on rabbits, and histopathologically. It was found that virus K is retained up to the 12th day post vaccination. If later on the presence of a virus was demonstrated it was believed that a wild virus participated. The virus was found in the spleen, lymph nodes, tonsils, and occasionally in the kidneys. Histologically, there were changes in the central nervous system under the form of nonsuppurative meningoencephalitis, dystrophic and fibroblastic proliferations in the kidneys, and necrobiotic and necrotic areas in the liver. They proved analogous to the changes found in spontaneously affected pigs; it was believed that there was no difference in the tropism of the vaccinal and the wild virus of swine fever. The results obtained improve the laboratory diagnostics of the classic form of swine fever.