Disinfection of foot-and-mouth disease and African swine fever viruses with citric acid and sodium hypochlorite on birch wood carriers

Transboundary animal disease viruses such as foot-and-mouth disease virus (FMDV) and African swine fever virus (ASFV) are highly contagious and cause severe morbidity and mortality in livestock. Proper disinfection during an outbreak can help prevent virus spread and will shorten the time for contaminated agriculture facilities to return to food production. Wood surfaces are prevalent at these locations, but there is no standardized method for porous surface disinfection; commercial disinfectants are only certified for use on hard, nonporous surfaces. To model porous surface disinfection in the laboratory, FMDV and ASFV stocks were dried on wood coupons and exposed to citric acid or sodium hypochlorite. We found that 2% citric acid was effective at inactivating both viruses dried on a wood surface by 30 min at 22°C. While 2000 ppm sodium hypochlorite was capable of inactivating ASFV on wood under these conditions, this chemical did not meet the 4-log disinfection threshold for FMDV. Taken together, our data supports the use of chemical disinfectants containing at least 2% citric acid for porous surface disinfection of FMDV and ASFV.