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

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 28, 2011
Publication Date: April 23, 2012
Repository URL: http://handle.nal.usda.gov/10113/54491
Citation: Krug, P.W., Larson, C.R., Eslami, A.C., Rodriguez, L.L. 2012. Disinfection of foot-and-mouth disease and African swine fever viruses with citric acid and sodium hypochlorite on birch wood carriers. Veterinary Microbiology. 156(1-2):96-101.

Interpretive Summary: Transboundary 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. Accidental or intentional introduction of these viruses into non-endemic countries can result in the culling of a large proportion of resident livestock, causing enormous economic losses. Proper disinfection during an outbreak can help prevent virus spread and will shorten the time for contaminated agriculture facilities to return to food production. Porous surfaces present a challenge because disinfectants must penetrate into the surface to effectively inactivate the viruses. To model porous surface disinfection in the laboratory, we modified our nonporous surface disinfection assay to work with small squares of birch veneer. We found that 2 percent citric acid was effective at a minimum of 99.99 percent disinfection of both viruses dried on the wood surface after a thirty-minute contact time. While 2000 ppm sodium hypochlorite was capable of inactivating ASFV on wood, this chemical did not meet the 99.99 percent threshold for FMDV disinfection. Thus, we recommend 2 percent citric acid for porous surface disinfection of FMDV and ASFV.

Technical Abstract: 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 percent citric acid was effective at inactivating both viruses dried on a wood surface by thirty minutes at 22 degrees Celsius. 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 percent citric acid for porous surface disinfection of FMDV and ASFV.