Inactivation of Coxsackievirus B4, Feline Calicivirus and Herpes Simplex Virus Type 1: Unexpected Virucidal Effect of a Disinfectant on a Non-Enveloped Virus Applied onto a Surface

Objective: To evaluate the effect of a disinfectant onto viruses in suspension on the one hand and applied onto a surface on the other. Methods: A system combining flocked swabs to recover viruses dried onto stainless steel carriers and gel filtration to eliminate cytotoxic products has been developed to study the virucidal effect of a quaternary ammonium-based disinfectant towards herpes simplex virus type 1 (HSV-1), coxsackievirus B4 (CVB4) and feline calicivirus F9 (FCV). The recovery of FCV has been estimated by RT real-time PCR. Results: HSV-1, CVB4 and FCV had a titer over 10 4 TCID 50 · ml -1 after 2 h drying and were recovered from the carriers using flocked swabs. HSV-1 was inactivated in suspension and on stainless steel carriers by the disinfectant (a reduction factor of 4 and 2.83 log, respectively) whereas CVB4 was resistant. The reduction of infectious titer was moderate, 1.5 log in 30 min, when FCV was in suspension, whereas it was up to 4 log in 10 min when the virus was dried on a carrier. Dried FCV was efficiently recovered from carriers as demonstrated by RT real-time PCR. Conclusion: A non-enveloped virus, FCV, applied on a surface, but not in suspension, was inactivated by a quaternary ammonium-based disinfectant. The resistance of viruses applied onto a surface to the effect of disinfectants should be investigated further.