VALIDATION OF DISINFECTION BY DIRECTED AND NON-DIRECTED PROCESSES IN THE BSL3 LABORATORY HANDLING LIVE FOOT-AND-MOUTH DISEASE VIRUS
Résumé
Introduction
In laboratories handling live foot-and-mouth disease virus (FMDV), strict biosecurity measures are applied, including for the entry and exit of personnel as well as for the decontamination of all equipment and the various surfaces in the laboratory. Today, the most commonly used disinfectant for this virus is formaldehyde which is toxic for humans. The objective of our study is to validate FMDV inactivation efficiency by new less toxic products.
Materials and Methods
Depending on their use, the efficiency of disinfectant products was tested using different methods according to the French standard NF-T-72281 November 2014: (i) by spray for laboratory surfaces (directed disinfection process), (ii) by misting for large equipment or for the whole laboratory (airborne disinfection - non-directed process). Efficiency tests consisted in letting the virus in contact with the disinfectant product for a setted time, adapted to the product and the method used. The result was expressed as a reduction in the viral load determined by virus titration on cells. For the disinfection of the different surfaces, the virus was put in contact with a 0.5% citric acid solution for two minutes on a support. Six FMD serotypes were tested (O, A, Asia-1, SAT1, SAT2, SAT3) by this method. For airborne disinfection, the virus serotypes O and SAT2 were exposed to a 35% hydrogen peroxide solution for two hours.
Results
As 0.5% citric acid is not cytotoxic, the recovery liquid from the supports could be inoculated directly on sensitive cells for virus detection and titration. For the highly cytotoxic 35% hydrogen peroxide, the recovery fluid had to be diluted and the large volume method was used. The results of both methods show an absence of virus in the recovery fluid after testing.
Discussion
In view of these initial positive results, we are continuing to test the effectiveness of these two products, which are less-toxic to humans under the right conditions of use. At the end of this study, these disinfection methods could be an alternative to other methods that use more toxic products.