Chemical disinfection of high-consequence transboundary animal disease viruses on nonporous surfaces

Disinfection is a critical part of the response to transboundary animal disease virus (TADV) outbreaks by inactivating viruses on fomites to help control infection. To model the inactivation of TADV on fomites, we tested selected chemicals to inactivate Foot and Mouth Disease virus (FMDV), African Swine Fever virus (ASFV), and Classical Swine Fever virus (CSFV) dried on steel and plastic surfaces. For each of these viruses, we observed a 2 to 3 log reduction of infectivity due to drying alone. We applied a modified surface disinfection method to determine the efficacy of selected disinfectants to inactivate surface-dried high-titer stocks of these three structurally different TADV. ASFV and FMDV were susceptible to sodium hypochlorite (500 and 1000 ppm, respectively) and citric acid (1%) resulting in complete disinfection. Sodium carbonate (4%), while able to reduce FMDV infectivity by greater than 4-log units, only reduced ASFV by 3 logs. Citric acid (2%) did not totally inactivate dried CSFV, suggesting it may not be completely effective for disinfection in the field. Based on these data we recommend disinfectants be formulated with a minimum of 1000 ppm sodium hypochlorite for ASFV and CSFV disinfection, and a minimum of 1% citric acid for FMDV disinfection.