Will TADD Process Inactivate ASF Virus in Transport Trailers?
Swine transportation plays a big role in spreading infectious pathogens, including African swine fever (ASF) virus. University of Nebraska researchers investigated if it is possible to effectively inactivate ASF virus in the presence of organic materials such as feces and bedding through the use of thermal-assisted drying and decontamination (TADD). TADD commonly operates at a temperature between 63°C and 71°C. The study, funded by the Swine Health Information Center (SHIC), says power washing surfaces with room temperature water followed by baking efficiently removed contaminated material.
Conducted in Vietnam, the study was made possible by funding from SHIC through a USDA Foreign Agricultural Service grant. SHIC reports that Hiep Vu, Nebraska Center for Virology and Department of Animal Science, University of Nebraska-Lincoln, designed the study to determine the optimal baking time and temperature required to completely inactivate ASF virus on aluminum surfaces contaminated with swine feces. Researchers tested the inactivation efficiency of contaminated trays under three conditions:
A. Baking contaminated aluminum trays at 54°C and 63°C for five, 10 and 15 minutes.
B. Power washing the tray surface with water at room temperature followed by baking at 54°C and 63°C for five, 10, and 15 minutes.
C. Power washing the tray surface with water, spraying disinfectant (Virkon-S), followed by baking at 54°C and 63°C for five, 10 and 15 minutes.
Two different methods, including PCR to detect viral genomic DNA and virus isolation to detect infectious virus, were used to evaluate the efficiency of the treatments, SHIC reports.
In condition A, swabs collected from contaminated trays at all time-points post incubation at 54°C and 63°C were positive by PCR, indicating that heat treatment could not eliminate viral genomic DNA, SHIC reports. However, swabs collected from contaminated tray at five minutes post incubation at either 54°C or 63°C were negative by virus isolation, indicating that holding ASF virus in the presence of feces at 54°C for five minutes is sufficient to inactivate the virus.
In conditions B and C, only two swabs collected after washing and baking were positive by PCR at high Ct value (e.g. 37.03). These swabs were negative for virus isolation, SHIC reports.
Under the conditions of this study, power washing of the trays with water at room temperature, with or without the use of disinfectant, and then followed by baking efficiently removed contaminated material from the trays.
Results obtained from this research study provide valuable information for the development of effective sanitation protocols to disinfect animal trailers to reduce the spread of ASF virus, SHIC reports.
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