Chapter V 



Inactivation of Viruses 



S. Gard and 0. Maal0e, 



Karolinska Institutet Medical School, Stockholm, Sweden 



University Institute of Microbiology, Copenhagen, Denmark 



I. Introduction 360 



II. Physical Agents 361 



A. Mechanical Treatments 361 



1 . Sonic Irradiation 361 



2. Siu-face Inactivation 363 



3. Inactivation at High Pressure 364 



B. Ionizing and Nonionizing Radiations 364 



1 . General Aspects 364 



2. Ionizing Radiation 366 



a. X-Rays 366 



b. a-Rays and Other Hea^'y- Particle Rays 372 



3. Nonionizing Radiation 374 



a. Far UV Light 374 



b. Near UV and Visible Light 379 



4. Inactivation Due to Decay of Incorporated Radioactive Phosphorus . . 380 



III. Phj'sicochemical Factors 382 



A. Heat Inactivation 382 



1 . Sterilization 382 



2. Theoretical Aspects 384 



J5. Resistance to Low Temj eratuie and to Desicc atiou 387 



1. Freezing and Thawing 387 



2. Desiccation 388 



C. Virus Stability and pH 389 



D. Salt Effects 390 



1. Stability As a Function of Salt Concentration and Ionic Composition 390 



2. Osmotic Shock 391 



IV. Chemical Agents 392 



A. Chemical Alterations of the Virus Particle not associated with Loss of 



Infectivity 392 



B. Formaldehyde 398 



1. Tobacco Mosaic Virus 399 



2. Bacteriophage 400 



3. Poxvu-us 400 



4. Myxovirus 401 



5. Poliovirus 401 



6. Foot-and-Mouth Disease Virus 403 



7. General Remarks 403 



C. Protein-Denaturing Agents 405 



D. Oxidizing Agents 407 



359 



