Modeling the transboundary risk of feed ingredients contaminated with porcine epidemic diarrhea virus

Abstract

BackgroundThis study describes a model developed to evaluate the transboundary risk of PEDV-contaminated swine feed ingredients and the effect of two mitigation strategies during a simulated transport event from China to the US.ResultsIngredients imported to the USA from China, including organic & conventional soybeans and meal, lysine hydrochloride, D-L methionine, tryptophan, Vitamins A, D & E, choline, carriers (rice hulls, corn cobs) and feed grade tetracycline, were inoculated with PEDV. Control ingredients, and treatments (ingredients plus a liquid antimicrobial (SalCURB, Kemin Industries (LA) or a 2 % custom medium chain fatty acid blend (MCFA)) were tested. The model ran for 37 days, simulating transport of cargo from Beijing, China to Des Moines, IA, US from December 23, 2012 to January 28, 2013. To mimic conditions on land and sea, historical temperature and percent relative humidity (% RH) data were programmed into an environmental chamber which stored all containers. To evaluate PEDV viability over time, ingredients were organized into 1 of 4 batches of samples, each batch representing a specific segment of transport. Batch 1 (segment 1) simulated transport of contaminated ingredients from manufacturing plants in Beijing (day 1 post-contamination (PC)). Batch 2 (segments 1 and 2) simulated manufacturing and delivery to Shanghai, including time in Anquing terminal awaiting shipment (days 1–8 PC). Batch 3 (segments 1, 2 and 3) represented time in China, the crossing of the Pacific and entry to the US at the San Francisco, CA terminal (day 1–27 PC). Batch 4 (segments 1–4) represented the previous events, including transport to Des Moines, IA (days 1–37 PC). Across control (non-treated) ingredients, viable PEDV was detected in soybean meal (organic and conventional), Vitamin D, lysine hydrochloride and choline chloride. In contrast, viable PEDV was not detected in any samples treated with LA or MCFA.ConclusionsThese results demonstrate the ability of PEDV to survive in a subset of feed ingredients using a model simulating shipment from China to the US. This is proof of concept suggesting that contaminated feed ingredients could serve as transboundary risk factors for PEDV, along with the identification of effective mitigation options.

Lactogenic immunity and vaccines for porcine epidemic diarrhea virus (PEDV): Historical and current concepts

“…Despite all of the efforts to control intra and inter-farm PEDV transmission, swine herds are still vulnerable to infection through the movement of contaminated feed. Recent field reports and experiments support the movement of contaminated feed as a likely source of infection in a number of once naïve farms (Bowman et al, 2015;Dee et al, 2014;Dee et al, 2016;Kochhar, 2014) and supports the working hypothesis of the Chinese origin of the PEDV epidemic (Huang et al, 2013).…”

Evolution, antigenicity and pathogenicity of global porcine epidemic diarrhea virus strains

“…Fecal-oral transmission is the major route for the spread of PEDV in swine. Contaminated feed and feed ingredients may serve as vehicles for PEDV transmission to naïve pigs (Dee et al, 2014(Dee et al, , 2016Pasick et al, 2014). In addition, evidence of PEDV aerosol transmission has been reported (Alonso et al, 2014).…”

Identifying outbreaks of Porcine Epidemic Diarrhea virus through animal movements and spatial neighborhoods

“…Indirect transmission between farms may also be possible via airborne mechanisms 25,26 . Potential environmental conditions that may facilitate virus survivability in the environment include temperature 27 and relative humidity 28 , but these environmental factors have not been integrated into broader analyses of risk factors for transmission. More generally, there is a lack of quantitative knowledge about the impact of meteorological, environmental, and topographic features (i.e.…”