The Inactivation of Influenza Virus by Certain Vapors.

Although nuimerous studies have been reported on the virucidal activity of' various substances used as aerosolic mists or in direct contact with the influenza virus, only two studies have been published describing the action of vapors on viruses, so far as the writers are aware. Remlinger and Bailly (1942) showed that when the viruses of rabies, pseudorabies, or eastern equine encephalomyelitis were exposed to the vapors of eucalyptus oil in a static atmosphere at 21 C, these viruses were innocuous when subsequently injected into susceptible animals. Exposure to the vapors for 51 hours to 2 days and 8 hours, the time depending upon the virus used, was required to destroy infectivity. Recently Stone and Burnet (1945) found that vapors of bromine, chlorine, and especially iodine inactivated the influenza virus. When mice were placed in a chamber containing atomized influenza virus and sufficient iodine vapor, the mice did not become infected. This protection was shown to result from inactivation of the virus in the air rather than from a prophylactic or therapeutic action of the vapors on the mice. The present report describes a simple in vitro method for detecting the virucidal action of vapors from volatile substances and gives the results obtained with 48 substances tested by this method. A brief account is also presented of the treatment of infected mice with vapors of one of the substances that inactivated the influenza virus in vitro.