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Abstract

In this paper, the results of biological recognition of an attenuated strain of S.dublin31 were studied in comparison with the virulent strain S.dublin 373. Our studies showed that the attenuated strain S.dublin 31 and the virulent strain S.dublin373 retained the basic cultural and biochemical properties inherent inherent in this speciesThe residual virulence of the vaccine strain S.dublin 31 was tested in comparison with the virulent culture of S.dublin 373 on white mice, guinea pigs and calves in several repetitions, taking into account their survival, dissemination of the process and the elimination of the culture of the vaccine
strain. Unlike the virulent culture of S.dublin 373, the attenuated strain S.dublin 31 has a stable residual virulence.