Inactivation of influenza A virus by gentian violet (GV) and GV-dyed cotton cloth, and bactericidal activities of these agents

Recently we have heard warnings of an outbreak of a highly pathogenic avian influenza virus (H5N1). Although, to prevent such infections we must prepare anti-viral drugs and type-specific vaccines against influenza, we need various simple and effective protection methods, such as the use of face masks for public health. Also, in any consideration of bacterial infections, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE), and multidrug-resistant Pseudomonas aeruginosa (MDRP) also pose serious concerns which must be addressed. I examined the antiviral activity of gentian violet (GV) and GV-dyed cloth against the influenza A (H1N1) virus. Time-kill studies were carried out, and the virus titer was determined based on the 50% tissue culture infective dose (TCID50). The minimum inhibitory concentrations (MICs) of GV against bacteria were also determined, and the killing activities of the GV-dyed cloth were judged from viable cell counts. GV immediately killed the influenza A virus and this was confirmed by electron microscopy. Moreover, cloth dyed with a combination of GV and copper showed not only excellent antiviral activity but also prominent bactericidal activities.