It is widely known and understood that transportation vehicles can serve as a potential route of pathogen transmission within swine production systems. The movement of these vehicles within multiple sites within a production system or even between farms between production systems presents a significant risk of contamination with pathogens of concern such as porcine epidemic diarrhea virus (PEDV) and porcine reproductive and respiratory syndrome virus (PRRSV). To date, there are relatively limited options available for producers for practical decontamination of the interior surfaces of truck cabs. Robust data is available for exterior decontamination, but interior surfaces are much more challenging to decontaminate due to the limited ability to use thorough cleaning such as pressure washing and sanitation using aggressive disinfectants. Therefore, the objective of this experiment was to evaluate several decontamination methods for mitigation of PEDV and PRRSV within truck cabs. In order to accomplish this objective, a total of 3 real-world scale truck cabs were modified to be used in a BSL-2 research facility using multiple surface types including fabric, rubber, and plastic. Surfaces were inoculated with either PEDV alone, PRRSV alone, PEDV + an organic matter mixture of feces and dirt, or PRRSV + organic mixture. Practical decontamination methods were then applied using application with a pump sprayer, using a Hurricane fogger system, and using a commercially available gaseous chlorine dioxide system. There was a significant disinfectant × surface interaction (P < 0.0001) indicating that the disinfectant treatment efficacy differed based on surface. Several differences were observed within different combinations of disinfectant and surface indicating that under the conditions of this study the ability for different disinfectants to reduce detection of PEDV and PRRSV genetic material differed depending on the surface being evaluated. To build upon this work, an additional investigation was performed to evaluate the efficacy of environmental sample processing technique prior to PCR analysis. Minor differences were observed between techniques depending on the level of organic material present on the surface, but results would indicate that with all levels of environmental contamination centrifugation of environmental samples prior to PCR analysis would result in the most consistent results. In summary, these data highlight that it is important to consider the surface of interest when implementing disinfectant protocols. In general, most disinfectant applications were only able to reduce the quantity of detectable virus, but not completely eliminate it from surface. However, additional research is necessary to understand the viability of residual virus on disinfected surfaces. Furthermore, it is recommended that environmental samples be processed with a centrifugation step prior to PCR analysis to maximize diagnostic sensitivity.
Questions regarding this research or its implications can be directed to the Principal Investigator, Dr. Jordan Gebhardt, at jgebhardt@vet.k-state.edu.
Key Findings:
Minor differences in detection of PEDV and PRRSV RNA was observed depending upon surface following application of decontamination products.
The impact of disinfection treatments on viral infectivity is not known and future work would be needed to characterize further.
Organic material in environmental samples potentially inhibit PCR analysis.
Processing samples prior to PCR can improve diagnostic sensitivity and centrifugation maximizes sensitivity for detection of viral RNA.
