Published online by Cambridge University Press: 15 May 2009
Summarising the results obtained in this series of experiments, it would appear that, in the case of Bact. aertrycke infection spreading among a closed community of mice:
(1) The character and severity of the epidemic are mainly determined by the virulence of the infecting bacterial strain.
(2) Strains of high virulence may give rise to non-fatal persistent infections, maintaining their full virulence over long periods of time within the spleens of the infected mice.
(3) Strains of low virulence may persist for long periods of time within such closed populations, spreading to some extent among the mice at risk, causing occasional deaths, and leading to an appreciable number of latent infections.
(4) It would appear that virulence and power to spread are highly corre lated.