PSVI-7 Evaluation of Feed Mitigant Efficacy for Control of Porcine Epidemic Diarrhea Virus and Porcine Reproductive and Respiratory Syndrome Virus When Inoculated Either Alone or Together

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 217-218
Author(s):  
Catherine Elijah ◽  
G E Nichols ◽  
J T Gebhardt ◽  
Cassandra K Jones ◽  
Jason C Woodworth ◽  
...  

Abstract Research has demonstrated that swine feed can be a fomite for viral transmission and certain feed additives can effectively reduce viral contamination. However, additional information is needed to evaluate the efficacy of additives when feed is inoculated with more than one virus. The objective of this study was to evaluate the efficacy of two feed additives for mitigation of porcine epidemic diarrhea virus (PEDV) and porcine reproductive and respiratory syndrome virus (PRRSV) when inoculated individually or together. Feed additives included: 1) no treatment, 2) 0.33% commercial formaldehyde-based product (Sal Curb, Kemin Industries, Des Moines, IA), and 3) 0.50% medium chain fatty acids blend (MCFA; 1:1:1 ratio of C6:C8:C10, Sigma Aldrich, St. Louis, MO). Samples were inoculated with PEDV and PRRSV alone or together at an inoculation concentration of 106 TCID50/g for all viruses. Once inoculated, feed was stored at ambient temperature for 24-h before analyzed via qRT-PCR. For samples inoculated with PEDV or PRRSV alone, a qRT-PCR assay was used which was designed to detect PEDV or PRRSV nucleic acid. For co-inoculated samples, an assay was designed to independently detect both PEDV and PRRSV within a single reaction. For PEDV alone, there was marginally significant evidence that feed additives resulted in differences in cycle threshold (Ct) value (P = 0.052), but no evidence was observed for pairwise differences. For PRRSV alone, formaldehyde increased Ct compared to the untreated control and MCFA treatment (P < 0.05). For co-infection of PRRSV and PEDV, MCFA and formaldehyde increased Ct (P < 0.05) in comparison to non-treated feed. In summary, formaldehyde increased Ct values in feed when contaminated with PRRSV while both mitigants increased Ct value in feed when co-inoculated with PRRSV and PEDV.

2018 ◽  
Vol 3 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Jordan T Gebhardt ◽  
Jason C Woodworth ◽  
Cassandra K Jones ◽  
Mike D Tokach ◽  
Philip C Gauger ◽  
...  

Abstract Mitigation of porcine epidemic diarrhea virus (PEDV) was assessed using two feed additives (0.5% inclusion of a benzoic acid [BA] product and 0.02% inclusion of an essential oil [EO] product; DSM Nutritional Products Inc., Parsippany, NJ), and combination of both products (0.5% BA and 0.02% EO) in spray-dried porcine plasma (SDPP) and a swine gestation diet (FEED) as determined by real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and bioassay. Viral RNA quantification was performed at 7 sampling days post-laboratory inoculation (d 0, 1, 3, 7, 14, 21, and 42) and infectivity was assessed via bioassay with 10-d-old pigs. There was a tendency for treatment × feed matrix × day interaction (P = 0.094), in which the cycle threshold (Ct) value increased over time in FEED when treated with both feed additives, whereas there was no increase over time observed in SDPP treated with both feed additives. There was a feed matrix × day interaction (P < 0.001) in which Ct increased over time in FEED, whereas very little increase over time was observed in SDPP. A tendency for a treatment × feed matrix effect (P = 0.085) was observed where FEED treated with the combination of EO and BA had a greater (P < 0.05) PEDV Ct value than other FEED treatments, and all SDPP treatments had the lower PEDV Ct values compared to FEED treatments (P < 0.05). Overall, the combination of both feed additives was most effective at reducing the quantity of genetic material as detected by qRT-PCR (P < 0.001) compared to either additive alone or no feed additive. Virus shedding was observed in the d 7 postinoculation SDPP treatment that was treated with both feed additives, as well as d 0 untreated FEED and d 0 FEED treated with both feed additives. No other treatment bioassay room had detectible RNA shed and detected in fecal swabs or cecal contents. In summary, the combination of EO and BA enhanced the degradation of PEDV RNA in feed but had little impact on RNA degradation in SDPP. Both untreated feed and feed treated with the combination of EO and BA resulted in infection at d 0 post-laboratory inoculation; however, neither set of samples was infective at d 1 postinoculation. In addition, SDPP harbored greater levels of quantifiable RNA for a longer duration of time compared to FEED, and these viral particles remained viable for a longer duration of time indicating differences in viral stability exist between different feed matrices.


2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 216-217
Author(s):  
O L Harrison ◽  
G E Nichols ◽  
J T Gebhardt ◽  
Cassandra K Jones ◽  
Jason C Woodworth ◽  
...  

Abstract Recent research has demonstrated that swine viruses can be transmitted via feed. Chemical feed additives have been suggested for the mitigation of these viruses in complete feed. Therefore, the objective of this study was to evaluate the efficacy of a commercially available formaldehyde-based feed additive, medium chain fatty acid blend (MCFA), and commercially available fatty acid-based products for mitigation of porcine epidemic diarrhea virus (PEDV) and porcine reproductive and respiratory syndrome virus (PRRSV) in a feed matrix. Treatments consisted of: 1) non-treated positive control, 2) 0.33% commercial formaldehyde-based product (Sal Curb; Kemin Industries, Inc.; Des Moines, IA), 3) 0.5% MCFA blend (1:1:1 ratio of C6:0, C8:0, and C10:0, Sigma Aldrich, St. Louis, MO), 4) 0.25%, 5) 0.5%, or 6) 1% of commercial dry mono and diglyceride-based product (Furst Strike; Furst-McNess Company, Freeport, IL), 7) 0.25%, 8) 0.5%, or 9) 1% of commercial dry mono and diglyceride-based product (Furst Protect; Furst-McNess Company, Freeport, IL), 10) 0.25%, 11) 0.5%, or 12) 1% dry mono and diglyceride-based experimental product (Furst-McNess Company, Freeport, IL) with 3 replications/treatment. Treatments were applied to complete swine feed before inoculation with 106 TCID50/g of feed with PEDV or PRRSV. Post inoculation feed was held at ambient temperature for 24 h before being analyzed via qRT-PCR. The analyzed values represent the cycle threshold. Formaldehyde and MCFA decreased (P < 0.05) the detectable RNA of PEDV and PRRSV compared to all other treatments. Furst Strike, Furst Protect, and the experimental product did not significantly impact detectability of PEDV or PRRSV RNA. In conclusion, MCFA and formaldehyde treatments are effective at reducing detection of RNA from PEDV and PRRSV in feed.


2020 ◽  
Vol 51 (1) ◽  
Author(s):  
Pengcheng Wang ◽  
Juan Bai ◽  
Xuewei Liu ◽  
Mi Wang ◽  
Xianwei Wang ◽  
...  

Abstract Porcine epidemic diarrhea virus (PEDV) causes lethal diarrhea in suckling piglets, leading to severe economic losses worldwide. There is an urgent need to find new therapeutic methods to prevent and control PEDV. Not only is there a shortage of commercial anti-PEDV drugs, but available commercial vaccines fail to protect against highly virulent PEDV variants. We screened an FDA-approved library of 911 natural products and found that tomatidine, a steroidal alkaloid extracted from the skin and leaves of tomatoes, demonstrates significant inhibition of PEDV replication in Vero and IPEC-J2 cells in vitro. Molecular docking and molecular dynamics analysis predicted interactions between tomatidine and the active pocket of PEDV 3CL protease, which were confirmed by fluorescence spectroscopy and isothermal titration calorimetry (ITC). The inhibiting effect of tomatidine on 3CL protease was determined using cleavage visualization and FRET assay. Tomatidine-mediated blocking of 3CL protease activity in PEDV-infected cells was examined by western blot detection of the viral polyprotein in PEDV-infected cells. It indicates that tomatidine inhibits PEDV replication mainly by targeting 3CL protease. In addition, tomatidine also has antiviral activity against transmissible gastroenteritis virus (TGEV), porcine reproductive and respiratory syndrome virus (PRRSV), encephalo myocarditis virus (EMCV) and seneca virus A (SVA) in vitro. These results may be helpful in developing a new prophylactic and therapeutic strategy against PEDV and other swine disease infections.


2020 ◽  
Vol 98 (6) ◽  
Author(s):  
Annie B Lerner ◽  
Roger A Cochrane ◽  
Jordan T Gebhardt ◽  
Steve S Dritz ◽  
Cassandra K Jones ◽  
...  

Abstract Feed has been shown to be a vector for viral transmission. Four experiments were conducted to: 1) determine if medium chain fatty acids (MCFA) are effective mitigants when applied to feed both pre- and post-porcine epidemic diarrhea virus (PEDV) inoculation measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR), 2) evaluate varying levels and combinations of MCFA measured by qRT-PCR, and 3) evaluate selected treatments in bioassay to determine infectivity. In exp. 1, treatments were arranged in a 2 × 2 + 1 factorial with main effects of treatment (0.3% commercial formaldehyde [CF] product, Sal CURB [Kemin Industries, Inc.; Des Moines, IA], or 1% MCFA blend (Blend) of 1:1:1 C6:C8:C10 [PMI, Arden Hills, MN]) and timing of application (pre- or post-inoculation with PEDV) plus a positive control (PC; feed inoculated with PEDV and no treatment). All combinations of treatment and timing decreased detectable PEDV compared with the PC (P < 0.05). Pre-inoculation treatment elicited decreased magnitude of PEDV detection (cycle threshold value) compared with post-inoculation (P = 0.009). Magnitude of PEDV detection was decreased for CF compared with Blend (P < 0.0001). In exp. 2, pre-inoculation treatments consisted of: 1) PC, 2) 0.3% CF, 3 to 5) 0.125% to 0.33% C6:0, 6 to 8) 0.125% to 0.33% C8:0, 9 to 11) 0.125% to 0.33% C10:0, and 12 to 15) 0.125% to 0.66% C5:0. Treating feed with 0.33% C8:0 resulted in decreased (P < 0.05) PEDV detection compared with all other treatments. Increasing concentration of each individual MCFA decreased PEDV detectability (P < 0.042). In exp. 3, pre-inoculation treatments consisted of: 1) PC, 2) 0.3% CF, 3 to 7) 0.25% to 1% Blend, 8 to 10) 0.125% to 0.33% C6:0 + C8:0, 11 to 13) 0.125% to 0.33% C6:0 + C10:0, and 14 to 16) 0.125% to 0.33% C8:0 + C10:0. Treating feed with CF, 0.5% Blend, 0.75% Blend, 1% Blend, all levels of C6:0+C8:0, 0.25% C6:0 + 0.25% C10:0, 0.33% C6:0 + 0.33% C10:0, 0.25% C8:0 + 0.25% C10:0, or 0.33% C8:0 + 0.33% C10:0 elicited decreased detection of PEDV compared with PC (P < 0.05). Increasing concentration of each MCFA combination decreased PEDV detectability (linear, P < 0.012). In exp. 4, feed was treated pre-inoculation with: 1) no treatment (PC), 2) 0.3% CF, 3) 0.5% Blend, or 4) 0.3% C8:0 and analyzed via qRT-PCR and bioassay. Adding 0.5% Blend or 0.3% C8:0 resulted in decreased PEDV compared with PC and only PC resulted in a positive bioassay. Therefore, MCFA can decrease detection of PEDV in feed. Further, inclusion of lower levels of MCFA than previously evaluated are effective against PEDV.


Author(s):  
Mary B Muckey ◽  
Cassandra K Jones ◽  
Jason C Woodworth ◽  
Chad B Paulk ◽  
Steve S Dritz ◽  
...  

Abstract Porcine epidemic diarrhea virus (PEDV) is a possible biological hazard in feed mills. If the virus enters a feed mill, it becomes widely distributed and is difficult to decontaminate from both feed contact and non-feed contact surfaces. The objective of this study was to evaluate a variety of liquid and dry decontamination treatments that could be used to reduce the amount of PEDV found on feed manufacturing surfaces. This experiment was designed as a 5 × 10 factorial with 5 different feed manufacturing surfaces and 10 decontamination treatments with 3 replicates of each combination. Surfaces included stainless steel, solid polyethylene, woven polypropylene tote bag, rubber, and sealed concrete coupons. One mL (1×10 5 TCID50/mL) of stock PEDV was applied to each surface and allowed to dry completely for 60 min. Next, for decontamination requiring surface application, the application was performed and allowed 15 min contact time. The quantity of PEDV RNA was determined using quantitative reverse transcription PCR. A decontamination treatment × surface interaction was observed (P < 0.0001), indicating the efficacy of treatment is dependent upon the surface in which it is applied. Within the cement surfaces, the sodium hypochlorite resulted in the greatest (P < 0.05) cycle threshold (Ct) value, followed by formaldehyde which had a greater (P < 0.05) Ct value compared to remaining treatments. Within polyethylene, rubber, and stainless steel surfaces, the formaldehyde treated surfaces had the greatest Ct values (P < 0.05), followed by the sodium hypochlorite treatment, with other treatments all having lower Ct values (P < 0.05). For the woven polyethylene surfaces, the formaldehyde and sodium hypochlorite treatments had greater Ct values compared to all other treatments (P < 0.05). Additional research is necessary to identify the role of decontamination treatment on PEDV infectivity and develop methods for decontamination of feed manufacturing facilities.


Viruses ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 599 ◽  
Author(s):  
Yang Wu ◽  
Hongling Zhang ◽  
Zhaorong Shi ◽  
Jianfei Chen ◽  
Mingwei Li ◽  
...  

Porcine epidemic diarrhea virus (PEDV) causes a porcine disease associated with swine epidemic diarrhea. The type I interferon (IFN-I or IFN α/β) is a key mediator of innate antiviral response during virus infection. Different antagonistic strategies have been identified and determined as to how PEDV infection inhibits the host’s IFN responses to escape the host innate immune pathway, but the pathogenic mechanisms of PEDV infection are not fully elucidated. Our preliminary results revealed that endogenous TANK-binding kinase 1 (TBK1) and interferon regulatory factor 3 (IRF3), the key components in the IFN signaling pathway were downregulated in PEDV infected IPEC-J2 cells by iTRAQ analysis. In this study, we screened nsp15 as the most important viral encoded protein involved in TBK1 and IRF3 reduction. Endoribonuclease (EndoU) activity has been well determined for coronavirus nsp15. Three residues (H226, H241, and K282) of PEDV nsp15 were identified as critical amino acids for PEDV EndoU but not D265, which was not well correlated with published results of other coronaviruses, such as severe acute respiratory syndrome virus (SARS-CoV). Moreover, PEDV nsp15 can directly degrade the RNA levels of TBK1 and IRF3 dependent on its EndoU activity to suppress IFN production and constrain the induction of IFN stimulated genes (ISGs), by which PEDV antagonizes the host innate response to facilitate its replication. Collectively, these results have confirmed that PEDV nsp15 was capable of subverting the IFN response by the RNA degradation of TBK1 and IRF3.


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