| Popis: |
Interest in the development of effective vaccines against plague has led to the isolation and study of Pasteurella pestis strains of lowered virulence and to fairly extensive use of living, so-called "avirulent" strains in vaccines for human populations.'-5 Other than their inability to produce progressive fatal infection in a susceptible host, these attenuated strains do not uniformly possess characteristics that distinguish them from fully virulent strains. Some of these strains, including ones extensively used as living vaccines, can actually multiply appreciably in mice and guinea pigs, although this multiplication is controlled before it assumes seri |
