Efficacy of two commercial disinfectants against porcine epidemic diarrhea virus (PEDV) in livestock trailers under freezing conditions

Abstract

Since its emergence in 2013, porcine epidemic diarrhea virus (PEDV) spread rapidly throughout the United States due, in part, to the mobile nature of the United States swine industry and contaminated livestock trailers. The mobile nature of the swine industry cannot easily be changed, but the risk associated with contaminated livestock trailers can be mitigated by performing proper trailer sanitation and decontamination protocols. The number of studies investigating methods for inactivating PEDV in livestock trailers is small, but growing. Current literature shows that multiple sanitation and disinfection procedures can inactivate PEDV including the industry-standard high-pressure wash with detergent, disinfection, and dry either naturally or with a thermo-assisted drying and decontamination facility. Additionally, a commonly used accelerated hydrogen peroxide disinfectant inactivated PEDV in the presence of swine feces at room temperature. Additional disinfectants need to be evaluated for efficacy against PEDV under cold temperatures because PEDV outbreaks tend to be more prevalent in the fall and winter months and the cold temperatures make a complete wash, disinfect, and dry of the livestock trailer between every load of pigs more difficult to complete. The first study investigated if the accelerated hydrogen peroxide disinfectant was capable of inactivating PEDV in swine feces on aluminum surfaces at -10⁰C. PEDV inactivation was assessed using a swine bioassay. Both the 1:16 and 1:32 dilutions of the accelerated hydrogen peroxide disinfectant, mixed with 10% propylene glycol as an anti-freezing agent, successfully inactivated PEDV in swine feces on metal surfaces at -10⁰C with a minimum of 40 minutes of contact time. A second study tested a peroxygen-based disinfectant for the ability to inactivate PEDV on aluminum surfaces at 4⁰C or -10⁰C. Swine bioassay was used to determine if PEDV remained infective after disinfection. Both the 1:100 and 1:600 dilutions of peroxygen-based disinfectant successfully inactivated PEDV in swine feces on metal surfaces at 4⁰C and -10⁰C with a minimum of 10 minutes of contact time. The results of the original research in this thesis and the literature review suggest that trailer sanitation and decontamination protocol involving washing to remove fecal and organic material, followed by chemical disinfection with an accelerated hydrogen peroxide, peroxygen-based, quaternary ammonium glutaraldehyde, phenol, sodium hypochlorite, or quaternary ammonium disinfectant product, and drying either naturally or through the use of a thermo-assisted drying and decontamination system are efficacious for inactivating PEDV under field conditions. While the studies conducted in this thesis demonstrate that PEDV can be