Background: Contaminated transport is a significant risk factor for the spread of PEDV between farms. The purpose of this study was to evaluate an existing sanitation protocol, previously validated for PRRSV, for its effect on PEDV.
Design: Trailer models (eight, 2’x4’x4’ aluminum boxes) were used for this study. Treatment models (n=6) were contaminated using a standard protocol involving known quantities of feces, shavings and 6 logs/total dose of PEDV, courtesy of Dr. Eric Nelson, SDSU. After 1 hour of contact time, models were scraped to remove physical debris, treated with a detergent (Barnstorm, 2oz/gallon), washed, disinfected (Synergize, 1oz/gallon) and dried using room temperature air. After each step, the internal surfaces of the models were sampled using Swiffer pads and tested by PCR for the presence of PEDV RNA at the SDSU VDL. Sampling following the application of the Disinfectant and Drying (D&D) step occurred at 1 hour, 3 hours, 8 hours and 20 hours post-application. For the purpose of controls, disinfection time was limited to 6 seconds to represent actual time required for a full-size (53’) trailer. Disinfectant neutralizing broth was added to each Swiffer sample to inhibit disinfection activity at the “test-tube” level prior to PCR testing. In addition, a positive control model (contamination but no treatment) and a negative control model (contamination without virus followed by treatment) were included.
Findings: No significant change in PEDV Ct was detected in any of the sanitation steps prior to the D&D process. At the 1 hour sampling point, 4 of 6 treatment models were PCR-negative while 2 were PCR-positive, although with weak Ct levels and both samples were virus isolation (VI) negative. After 3 hours post D&D, PEDV RNA was no longer detectable in any treated model, despite the use of room-temperature air for drying. In contrast, PEDV RNA was detected in the positive control model throughout the sampling period while the negative control model remained PCR-negative.
Conclusion: These results validate the efficacy of this specific sanitation protocol against PEDV.
Source: Study conducted by Pipestone Applied Research and Preserve International and reported by the UMN Swine Health Monitoring Project