Chapter 



11 



The Inhibition of Virus 

 Reproduction by Chemical 

 Substances 



By FRANK L HORSFALL, JR. 



When a virus particle and a cell come to- 

 gether, events may begin which lead to the production of 

 more virus particles. If this occurs, it is said that the virus 

 particle is infective, the cell is susceptible, and virus repro- 

 duction has taken place. The concepts of infectivity and 

 susceptibility are inseparable; either is dependent on the 

 other. The capacity of the virus to infect cannot be demon- 

 strated without a susceptible cell, while the capacity of the 

 cell to support reproduction is determinable only with an 

 infective virus particle. 



If reproduction of the virus leads to abnormalities in cell 

 function, the virus is considered to be pathogenic. When 

 the number of abnormal cells becomes sufficiently large, 

 changes in tissue function may occur. Only when these 

 exceed a certain threshold level can disease be recognized. 

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