ABSTRACT
Because contaminated livestock trailers are a significant risk for transmitting viruses between herds, various methods of washing, disinfecting, and thermo-assisted drying and decontamination (TADD) have been evaluated for their effectiveness in inactivating porcine reproductive and respiratory syndrome virus (PRRSV) on contaminated surfaces. Information on when to expect negative qRT-PCR results after adequate trailer sanitation is lacking. The objective of this study was to evaluate whether there are conditions associated with washing-disinfectant-TADD procedures that will consistently produce a negative qRT-PCR result for the purpose of monitoring compliance with trailer sanitation and decontamination protocols for PRRSV on metal surfaces. 144 diamond plate aluminum coupons were spiked with PRRSV or phosphate-buffered saline (PBS) and treated with a designated disinfectant protocol. Disinfectants evaluated included multiple accelerated® hydrogen peroxide (AHP) disinfectants and a quaternary ammonium and glutaraldehyde combination disinfectant. Disinfectant was applied for 5 or 60 minutes of contact time at either 20 °C or -10 °C in a matrix of feces or PBS. All coupons were heated until the surface temperature of the coupon reached 71 °C and then held for 10 minutes to simulate TADD under field conditions. Post-treatment swabs for all treatment groups, except negative control groups, were positive by PRRSV qRT-PCR. Under the conditions evaluated in this study, consistently negative qRT-PCR results after treatments were not found. Therefore, for the purpose of monitoring compliance with trailer sanitation and decontamination protocols for PRRSV, alternatives to qRT-PCR should be explored.
Subject(s)
Decontamination , Disinfection , Industrial Microbiology , Metals , Porcine respiratory and reproductive syndrome virus , Reverse Transcriptase Polymerase Chain Reaction , Animals , Decontamination/standards , Desiccation , Disinfectants/pharmacology , Disinfection/standards , Hot Temperature , Industrial Microbiology/methods , Industrial Microbiology/standards , Porcine respiratory and reproductive syndrome virus/genetics , Reverse Transcriptase Polymerase Chain Reaction/veterinary , SwineABSTRACT
Porcine epidemic diarrhea virus (PEDV) spread rapidly across the United States in part due to contaminated livestock trailers. The objective of this study was to test a peroxygen-based disinfectant for the ability to inactivate PEDV on aluminum surfaces at 4⯰C or -10⯰C. Forty 3-week-old individually housed barrows were used as a bioassay to determine the infectivity of PEDV after treatment with either a 1:100 or 1:600 dilution of a peroxygen-based disinfectant with 10 or 30â¯min of contact time. One coupon matched to one pig was the experimental unit. Coupons in the positive control and disinfectant treatment groups were contaminated with 2â¯mL of feces spiked with PEDV. A negative control group was contaminated with PEDV-negative feces. Following treatment, the feces and disinfectant remaining in the coupons was collected and administered to pigs intragastrically. Rectal swabs were collected from pigs 3 and 7â¯days post-inoculation (DPI) and tested for PEDV by RT-qPCR. Samples from all coupons, except the negative control, were positive by RT-qPCR for PEDV before and after treatment. All rectal swabs from the pigs in the negative control and the seven disinfectant treatment groups were RT-qPCR negative for PEDV on 3 and 7 DPI. All pigs in the positive control at 4⯰C and 3 of 4 pigs in the positive control conducted at -10⯰C were RT-qPCR positive for PEDV on 3 and 7 DPI. Both the 1:100 and 1:600 dilutions of peroxygen-based disinfectant successfully inactivated PEDV under the conditions of this study.