Risk and Mitigation of African Swine Fever Virus in Feed

Abstract

Since the 2013 introduction of porcine epidemic diarrhea virus into the United States (U.S.), feed and feed ingredients have been recognized as potential routes for the introduction and transmission of foreign animal diseases of swine. Feed ingredients for swine diets are commodities traded worldwide, and the U.S. imports thousands of metric tons of feed ingredients each year from countries with circulating foreign animal diseases. African swine fever (ASF) is the most significant foreign animal disease threat to U.S. swine production, and the recent introduction of ASF into historically negative countries has heightened the risk for further spread. Laboratory investigations have characterized the stability of the ASF virus (ASFV) in feed ingredients subjected to transoceanic shipment conditions, ASFV transmissibility through the natural consumption of plant-based feed, and the mitigation potential of certain feed additives to inactivate ASFV in feed. This review describes the current knowledge of feed as a risk for swine viruses and the opportunities for mitigating the risk to protect U.S. pork production and the global swine population from ASF and other foreign animal diseases.

Modelling and assessing additional transmission routes for porcine reproductive and respiratory syndrome virus: vehicle movements and feed ingredients

“…A recent study developed a new mathematical model to reconstruct the between-farm PRRSV dynamics, revealed the role of between-farm pig movements, indirect contacts by farm-to-farm proximity, and the continued circulation of PRRSV within infected sites (re-break) (Galvis et al, 2021). Despite the promising results, the study did not fully consider indirect contacts formed by the between-farm transportation vehicles networks, which has been previously described as one the major modes of the between-farm transmission of disease in swine (Büttner and Krieter, 2020; Porphyre et al, 2020; Niederwerder, 2021), and also in other systems such as cattle (Yang et al, 2020).…”

“…Contaminated feed ingredients have been recognized as possible routes for between-farm pathogen transmission (Niederwerder, 2021), however the probabilities of PRRSV transmission through them have been described as relatively low (Cochrane et al, 2017; Ochoa et al, 2018). Dee et al 2020, experimental study demonstrated that pigs that consumed pellet feed contaminated with 1×10 5 TCID50/ml of PRRSV exibeted clinical signs (Dee et al, 2020).…”

“…Dee et al 2020, experimental study demonstrated that pigs that consumed pellet feed contaminated with 1×10 5 TCID50/ml of PRRSV exibeted clinical signs (Dee et al, 2020). Thus, it is worth noting that cross-contamination of feed ingredients may occur also after the pelleting process by the direct contact of contaminated fomites or feed mill workers (Niederwerder, 2021). In addition, it is important to acknowledge that inadequate pressure in combination or alone with temperature applied during pelleting process could reduce the probability to inactivate PRRSV, as observed in an experimental study with Porcine Epidemic Diarrhea Virus (PEDV) (Cochrane et al, 2017).…”

“…The dramatic change in the global epidemiological situation of African swine fever (ASF) spread has resulted in concerns about its spread via feed and transportation vehicles moving between-farms and countries (Lee et al, 2017; Elijah et al, 2021; Mighell and Ward, 2021; Niederwerder, 2021; Shurson et al, 2021). However, there is limited information about the contribution of both vehicle movements and the delivery of specific feed ingredients (i.e.…”

Evaluating the distribution of African swine fever virus within a feed mill environment following manufacture of inoculated feed

“…Multiple routes of ASFV transmission to domestic swine have been characterized including domestic swine to domestic swine, wild suids to domestic swine, and via the soft tick of the Ornithodoros genus serving as a vector [ 6 ]. Within these, multiple mechanisms of transmission can occur whereby domesticated swine become infected with ASFV including direct animal contact, contact with contaminated fomites, or exposure to contaminated feedstuffs or water [ 7 ]. Extended stability of ASFV within pork products has been widely documented [ 8 ], detection of ASFV DNA within pork products crossing international borders has been documented [ 9 , 10 ], and strong evidence of ASFV transmission via contaminated food products has been documented [ 11 , 12 ].…”