WALKER 



Day of Virus titers 



Tissue infection 4° c 25° C 36° C 



Figure 5. Virus in tissues of adult mice infected with Coxsackie virus* and held 

 at 4° G, 25° C, or 36° C. •Inoculated with 140 infant mouse LD50 i. p. 



duction or stress can account for the effect of cold on viral in- 

 fections. For discussion of another possible mechanism I want to 

 return to the model of Coxsackie virus infections in mice. In study- 

 ing the effect of cold on this infection, Boring and 1 (19 58) followed 

 the fate of virus in various tissues of infected mice. It was evident 

 that in mice at normal temperatures an initial viremia was followed 

 by significant viral multiplication only in the pancreas. But in mice 

 at 4° C, the virus multiplied to relatively high levels and produced 

 marked damage in several tissues. It was also found that if mice 

 were maintained at an elevated ambient temperature, viral multi- 

 plication was inhibited in all tissues, including the pancreas (Fig. 5). 

 In fact, even ifthe pancreatitis was allowed to progress for 36 hours 

 after inoculation, exposure to 36° C still brought about a prompt 

 drop in virus titer in the pancreas and rapid elimination of the 

 virus. An important point is that when rectal temperatures of mice 

 are measured during exposure to such temperatures, it can be 



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