VIRULENCE AND BACTERIAL INFECTION 



Days Post Number of Survivors at 

 Infection 5° C 15° C 25'' C 



Table II. Survival of mice infected with 10 "^ 

 Salmonella typhimurium. SH-U. (Derivai from >iatn 

 presente<l in J. Infect. IJis. IIO : 201-209. 1962.) 



cent (16 or 41) at 25° C were alive at 14 days. Deaths resulted sooner 

 at 5° C than at the two higher temperatures (P < 0.005 in both cases) 

 and mean survival times in animals succumbing to infection were 

 6.0, 8.5, and 8.7 days in order of increasing temperature. The ex- 

 periments were terminated at 14 days in order to avoid ambiguities 

 in interpreting the results. Five degeee exposure alone can cause 

 deaths if mice of the strain used are maintained at this temperature 

 for periods longer than two weeks. 



In a single experiment, 12 mice that had survived acclimatization 

 for two weeks at 5° C were then infected with 10 SR-UA. Fourteen 

 days later only one of twelve was still alive. Thus, survival at 5° C 

 in mice with this infection does not differ with or without two weeks 

 of prior acclimatization (P = 0.3). 



Infection with S. T3^himurium, SR-U 



Mice were infected intraperitoneally with 10^ cells of virulent 



219 



