A study aimed to evaluate various cleaning protocols to mitigate porcine epidemic diarrhea virus (PEDV) spread from a contaminated trailer to the farm through foot traffic between these two areas. Efficacy was evaluated across protocols including 1) positive control (no cleaning), 2) dry clean – scrape and bake (TADD), 3) volume hose wash and disinfect, 4) power wash and disinfect, and 5) negative control. Led by Dr. Rodger Main of Iowa State University, the study found that the volume hose and power wash and disinfect protocols demonstrated significant efficacy in reducing viral load on both trailer and farm-site surfaces.
Find the study industry summary here. Funding for this work was provided by the Swine Health Information Center Wean-to-Harvest Biosecurity Research Program, in partnership with the Foundation for Food & Agriculture Research and Pork Checkoff,
PEDV has posed a significant threat to the US swine industry since its initial introduction in 2013 and requires effective biosecurity measures for disease control. Livestock trailers used for transporting pigs play a major role in PEDV epidemiology if not adequately cleaned and disinfected. The objective of this study was to evaluate the efficacy of different cleaning and disinfection methods in reducing PEDV contamination from livestock trailers to farm-site loading areas, using molecular and bioassay techniques. Effective cleaning and disinfection of livestock trailers are crucial in mitigating PEDV spread. This study simulated foot traffic between farm-site areas and trailers to mimic field conditions and determined the efficacy of various cleaning treatments.
Five treatment groups were included in the study: 1) positive control, where no trailer cleaning occurred post-inoculation with PEDV; 2) scrape and bake (TADD), where trailers were scraped and swept to remove fecal matter followed by heat up to 71ºC; 3) volume hose wash and disinfect, where trailers were flushed out with a high volume hose followed by disinfectant; 4) power wash and disinfect, where trailers were first washed with a hose to remove gross fecal matter, then power washed at 1500 psi, followed by disinfectant; and 5) negative control, where trailers were inoculated with PEDV-negative feces and received no cleaning.
Different cleaning methods were applied, followed by a simulation of foot traffic to mimic real-world conditions. Trailers were sampled post-cleaning and after foot traffic simulation. PEDV presence was quantified using qPCR to measure viral load on trailer surfaces and farm loading areas. Bioassays were conducted by inoculating naïve pigs with samples recovered from the farm site area after applying the treatments to trailers. Statistical analyses, including ANOVA and Fisher’s Exact test, compared PEDV levels and positive PCR results across treatments.
Washing treatments, particularly flush-out volume hose and power wash and disinfect, demonstrated significant efficacy in reducing viral load on both the trailer and farm-site surfaces. For farm-site surface contamination, these methods achieved over 99% reduction in viral genomic copies compared to the positive control. This marked reduction is crucial in preventing infection of susceptible pigs and highlights the importance of effective washing protocols. The power wash and disinfect method emerged as highly effective, significantly reducing PEDV levels on trailer surfaces with most samples showing negative PCR results (three of five). The volume hose wash and disinfect method also demonstrated substantial efficacy in inactivating the virus as tested through swine bioassay, though some residual fecal material was observed.
Even though the scrape and bake method reduced viral load by more than 98% compared to the positive control, this method was not effective in terms of virus inactivation as the most pigs tested on bioassay became infected with PEDV (four of five replicates). All negative control replicates were negative on PCR testing of the sampled surfaces and remained negative on the bioassay after inoculation. Positive control samples showed high PEDV levels on trailer and farm site surfaces.
Researchers noted water-based washing procedures, especially power wash and disinfect, are highly effective in reducing PEDV contamination on livestock trailers and preventing transmission to pigs. Importantly, both volume hose and power wash treatments were effective in completely producing negative pigs on bioassays, indicating effectiveness in inactivating the remaining virus harvested from the trailer and farm-site surfaces. Overall, bioassay results indicated that only the positive control and scrape and bake treatments led to PEDV infection in pigs, while the other treatments successfully prevented viral transmission.
The study underscores the importance of thorough cleaning and disinfection protocols in enhancing biosecurity in swine production systems. Moreover, findings suggest routinely cleaning and disinfecting all market haul trailers leaving terminal points of concentration by either of the water-based trailer cleaning treatments could reduce inter-premises disease transmission associated with market haul transport and elevate preparedness across the US pork industry.
Foundation for Food & Agriculture Research
The Foundation for Food & Agriculture Research (FFAR) builds public-private partnerships to fund bold research addressing big food and agriculture challenges. FFAR was established in the 2014 Farm Bill to increase public agriculture research investments, fill knowledge gaps and complement US Department of Agriculture’s research agenda. FFAR’s model matches federal funding from Congress with private funding, delivering a powerful return on taxpayer investment. Through collaboration and partnerships, FFAR advances actionable science benefiting farmers, consumers and the environment. Connect: @FoundationFAR
Swine Health Information Center
The Swine Health Information Center, launched in 2015 with Pork Checkoff funding, protects and enhances the health of the US swine herd by minimizing the impact of emerging disease threats through preparedness, coordinated communications, global disease monitoring, analysis of swine health data, and targeted research investments. As a conduit of information and research, SHIC encourages sharing of its publications and research. Forward, reprint, and quote SHIC material freely. For more information, visit http://www.swinehealth.org or contact Dr. Megan Niederwerder at mniederwerder@swinehealth.org or Dr. Lisa Becton at lbecton@swinehealth.org.