l6 PHYSIOLOGICAL TRIGGERS 



(UV) sensitivity prior to entering a fourth, or reproductive, phase. Depending 

 on the temperature, multipHcation begins in about 6 hours. 



Evidence from the UV and lesion data suggest that the replicating unit may 

 be different from the in vitro rod in two properties — its UV sensitivity and its 

 inability to initiate a new infection. 



As multiplication continues, infectious units begin spreading to adjacent cells 

 in a continuous fashion. The rate is governed by chance alone.This continuous 

 spread of infectious units introduces virus into a new cell approximately every 3 

 hours. On the order of 12-16 hours elapse between infection and the subsequent 

 death of the cell. 



Shortly before the cell dies it produces approximately 200,000 unique, rod- 

 shaped nucleoprotein particles. Of these, only a small fraction appear to possess 

 the ability to initiate a new cycle of virus multiplication. 



