Survival of herpes simplex virus during cryosurgery with liquid nitrogen.

Because many viruses can survive extremely cold temperatures for extended periods of time, transmission of viral diseases from person to person using improper cryosurgical techniques might conceivably occur. To investigate the survivability of herpes simplex virus during cryotherapy, virus was first inoculated onto cotton-tipped applicators from either tissue cultures or from active lesions on patients, and then frozen for variable times in liquid nitrogen (-196 degrees C). After thawing, the applicators were cultured for the virus. The virus survived 12 hours of freezing (the maximum time of freezing in the study), which suggests that herpes simplex could be transmitted between cryosurgical patients if care is not taken to use separate cotton-tipped applicators and liquid nitrogen containers for each case.