Effect of mixing and feed batch sequencing on the prevalence and distribution of African swine fever virus in swine feed. Issue 1 (17th June 2021)

• Record Type: Journal Article
• Authors: Elijah, Catherine Grace; Trujillo, Jessie D.; Jones, Cassandra K.; Kwon, Taeyong; Stark, Charles R.; Cool, Konner R.; Paulk, Chad B.; Gaudreault, Natasha N.; Woodworth, Jason C.; Morozov, Igor; Gallardo, Carmina; Gebhardt, Jordan T.; Richt, Jürgen A.
• Other Names: Dee Scott guestEditor.; Spronk Gordon guestEditor.
• Is Part Of: Transboundary and emerging diseases. Volume 69:Issue 1(2022)
• Page Start: 115
• Page End: 120
• Publication Date: 2021-06-17
• Subjects: African swine fever virus -- bulk sampling -- feed batch sequencing -- feed safety; Veterinary medicine -- Periodicals; 636.089
• DOI: 10.1111/tbed.14177
• Languages: English
• ISSNs: 1865-1674

Abstract

Abstract: It is critical to have methods that can detect and mitigate the risk of African swine fever virus (ASFV) in potentially contaminated feed or ingredients bound for the United States. The purpose of this work was to evaluate feed batch sequencing as a mitigation technique for ASFV contamination in a feed mill, and to determine if a feed sampling method could identify ASFV following experimental inoculation. Batches of feed were manufactured in a BSL‐3Ag room at Kansas State University's Biosafety Research Institute in Manhattan, Kansas. First, the pilot feed manufacturing system mixed, conveyed, and discharged an ASFV‐free diet. Next, a diet was manufactured using the same equipment, but contained feed inoculated with ASFV for final concentration of 5.6 × 10 4 TCID50 /g. Then, four subsequent ASFV‐free batches of feed were manufactured. After discharging each batch into a collection container, 10 samples were collected in a double 'X' pattern. Samples were analysed using a qPCR assay for ASFV p72 gene then the cycle threshold (Ct) and Log10 genomic copy number (CN)/g of feed were determined. The qPCR Ct values ( p < .0001) and the Log10 genomic CN/g ( p < .0001) content of feed samples were impacted based on the batch of feed. Feed samples obtained after manufacturing the ASFV‐contaminated diet contained the greatest amounts of ASFV p72 DNA across all criteria ( p < .05). Quantity of ASFV p72 DNA decreased sequentially as additional batches of feed were manufactured, but was still detectable after batch sequence 4. This subsampling method was able to identify ASFV genetic material in feed samples using p72 qPCR. In summary, sequencing batches of feed decreases concentration of ASFV contamination in feed, but does not eliminate it. Bulk ingredients can be accurately evaluated for ASFV contamination by collecting 10 subsamples using the sampling method described herein. Future research is needed to evaluate if different mitigation techniques can reduce ASFV feed contamination.