African Swine Fever Virus: Has Recent Supply Chain Availability Impacted Biosecurity Measures in Washington State Leading to an Increased Risk of Introduction?
Vianca N. Philpotts, MS
Animal Feed Program Field Supervisor and PC Specialist -
Washington State Department of Agriculture (WSDA)
Abstract
African Swine Fever (ASF) Virus is a foreign animal disease (FAD) that affects the swine species. It has no zoonotic potential (ability to spread between animals and people) and there are no indications that this might change (Dixon et al., 2020), but the disease continues to have devastating effects on swine populations with significant economic losses. Although there are commercial vaccines in development, there is not one readily available for ASF and the current method of control is culling, which is the only solution in place to prevent continued spread. A study of biosecurity practices in Washington State was conducted to determine 1) if farm biosecurity procedures, plans and processes were implemented; 2) if pork farmers held knowledge of ASF and its transmission via feed and feed ingredients; 3) if Foreign Supplier Verification Programs (FSVP) were in use for imported products; and 4) concerns surrounding virus introduction onto farms or operations. This study was conducted by a survey that was distributed to farmers, importers, and employees of farms that handle pork and pork products for animal feed in WA State. Results show that WA State pork farmers and producers are generally aware of the components of a biosecurity plan and how ASF can spread through feed and feed ingredients, pork meat or pork meat by-products, and more than half of the survey participants indicated they have a biosecurity plan implemented for their operation. However, when asked if ASF was a topic of concern for their farm or operation, 60% of survey participants answered no. Therefore, additional outreach, education, and regulatory action is needed to protect swine farmers against ASF in Washington State.
Keywords: African Swine Fever, foreign animal disease, pig, swine, biosecurity, risks, animal feed
African Swine Fever Virus: Has Recent Supply Chain Availability Impacted Biosecurity Measures in Washington State Leading to an Increased Risk of Introduction?
Background
African Swine Fever (ASF) Virus is a foreign animal disease (FAD) that has not yet appeared in the United States (US), but is endemic to the sub-Saharan region of Africa. ASF has no zoonotic potential (ability to spread between animals and people) and there are no indications that this might change (Dixon, Chapman, Netherton, et al., 2020), but the disease continues to have devastating effects on swine populations with significant economic losses. ASF has been retroactively recognized as first appearing in 1907 in Kenya, and was initially contained in the sub-Saharan region until about 1957 when it was introduced to Western Europe via Portugal. The virus has since continued its rapid spread through all regions of Europe, into Asia, into the Americas and now sits at the doorstep of the lower 48 states with its recent re-introduction into the Dominican Republic in 2021.
The virus, which causes a hemorrhagic fever with high mortality rates (95-100%) in domestic pigs, can be spread by indirect and direct contact with other infected pigs (domestic and wild), ingestion of infected meat or feed, or a bite from an infected soft tick. However, once introduced into the domestic pig population, the virus does not need an arthropod vector for transmission (Blome, Franzke, Beer, 2020). Figure 1 shows the potential transmission cycle of ASF (Wageningen University & Research, n.d.).
Figure 1
Potential Transmission Cycle of African Swine Fever Virus
Source:https://www.wur.nl/en/Research-Results/Research-Institutes/Bioveterinary-Research/Animal-diseases/Virology/African-Swine-Fever-2.htm
There are some concerns with aspects of swine feed ingredients that includes their global sourcing for virus introduction. Although there are other risk factors, such as illegally smuggled pork products for introduction of ASF into the US, plant-based feeds and feed ingredients are of particular concern (Mur, et al., 2019). Similar to a study conducted by Scott, McCluskey, Brown-Reid, et. al., 2016 in the investigation of porcine epidemic diarrhea virus introduction into the United States, 12 common swine feed ingredients were used to examine the stability of the [Country of] Georgia 2007 ASF virus isolate. After inoculation and 30 days of fluctuating temperatures and humidity that mimicked transatlantic shipment conditions, the infectious virus was detected in 75% (9/12) of the tested ingredients, demonstrating that it is highly stable and able to withstand shipping conditions (Dee, Bauermann, Niederwerder, et al., (2018).
Due to US trade with infected countries in Europe, Asia, and other countries such as the Dominican Republic, there are potential weaknesses in the biosecurity plans of distributors, importers and farmers, given the virus stability during transport of feed ingredients as previously discussed. According to the Washington State Pork Producers (WSPP), as of 2022, most, if not all, pork farmers in WA are aware of ASF and have taken some measures to increase biosecurity on their farms. However, taking into account the mass global changes experienced within the past three years, whether or not farmers have been able to effectively update or maintain their biosecurity plans is uncertain.
The Secure Pork Supply Plan (SPS), developed with the support of United States Department of Agriculture (USDA) and the Pork Checkoff, has been widely adopted as a national standard for everyday and enhanced biosecurity plans to allow for permitting and continuity of business of pork products during a FAD outbreak. However, the plan does little to address biosecurity of feed outside of addressing spills. These plans are voluntary and there currently is not a state biosecurity plan in place for pork farmers for feed or feed ingredients, and each firm has the autonomy to design a plan they feel works best for their business. WSDA does have a FAD Response Plan; however, that plan only gives guidance on biosecurity and refers farmers to the official USDA Animal & Plant Health Inspection Service (APHIS) Biosecurity Standard Operating Procedures. Because of the limited guidance, lack of defined state regulation, and voluntary nature of the SPS plans, there appears to be an opportunity to improve biosecurity in WA State. Although there are commercial vaccines in development, there is not one readily available for ASF and the current method of control is culling, which is the only solution in place to prevent continued spread. Due to the lack of vaccine availability, ASF presents a threat to animal food safety and according to Blome (2018), the best method of prevention is increased biosecurity.
Problem Statement
The readiness status of biosecurity plans and procedures for addressing ASF in WA State at potential control nodes throughout the pork supply system is currently unknown.
Research Questions
What are the potential routes of entry into WA State for African Swine Fever?
What are the highest areas of risk for introduction of African Swine Fever into WA state?
In what ways do pork farmers utilize the draft WA State Foreign Animal Disease Response Plan document for potential outbreaks of ASF and other FADs?
What methods of prevention have pork farmers and importers of WA State implemented with the knowledge of how ASF can spread through feed ingredients, pork meat or pork meat by-products?
Methodology
There were two parts to this project, spanning a period of four months from October 2022 to February 2023. During the data collection phase, a mixed methodology approach was used, where quantitative and qualitative data were collected concurrently. Qualitative data was collected by targeted telephone conversations with the WA State Veterinarian, WA State Rapid Response Team (RRT) and Emergency Management Team members in regards to state biosecurity plans and concerns around ASF, and federal partners involved in ASF research studies on a national level. Participation was strictly voluntary and questions asked during the interview obtained information regarding: 1) WA State biosecurity procedures for ASF; 2) current statewide and federal operations surrounding ASF; and 3) virus inoculation trials and vaccine creation.
Quantitative data collection included a sixteen-question survey documenting: 1) farm biosecurity procedures, plans and processes surrounding mock investigations to ensure proper implementation of biosecurity plans; 2) knowledge of ASF and its transmission via feed ingredients; 3) Foreign Supplier Verification Programs (FSVP) for imported products; and 4) concerns surrounding virus introduction onto farms or operations. The study population for the survey included farmers, importers, and employees of farms that handle pork and pork products for animal feed in WA State. The survey was delivered electronically to members of listservs held by WSPP, WA State University (WSU), and WSDA’s Animal Feed Program (AFP). Written copies of the survey were administered during the Washington Swine Information Day (WSID) seminar. The survey was voluntarily taken by members of the aforementioned listservs and participants at the seminar.
Results
Interviews
A total of four professionals (WA State vet, RRT and Emergency Management team members, Animal Nutritionist and a Federal partner) agreed to be interviewed out of seven whom had been contacted to participate in this study. The duration of the interviews averaged about 60 minutes each. Responses during the interviews elicited information surrounding FAD response plans currently activated in WA State and discussions of active FAD outbreaks such as Highly Pathogenic Avian Influenza. Mentions of interagency collaboration with feral swine working groups and thoughts about commercial vaccine creation and distribution were also key points of the discussions. As mentioned in the background of this research paper, a point was made by one of the Emergency Management Team members during their interview that the US does have a FAD Preparedness and Response Plan (PReP) developed by USDA APHIS and WA State also has a FAD Response Plan for ASF that serves as a guideline for farmers with strategy and logistics. However, the projected use of these documents as a guideline when creating a biosecurity plan could not be estimated during the conversations. All state vets promote SPP for consistency and approval for interstate movement during an outbreak. During the 2021 and 2022 legislative sessions, WSDA lobbied to change the state law in order to prohibit the feeding of garbage to swine in the state allowed under the conditions of the federal Swine Health Protection Act (SHPA), but the proposed change was not passed. While not recommended, WA State does permit garbage feeding, under a license issued from the director and regular inspections. However, there have not been any applications from pork producers in WA State since 2015, indicating that no farmers are licensed to practice garbage feeding.
Survey Responses
The survey, administered electronically via email and Microsoft Forms, was distributed to an approximate total of 1,249 listserv subscribers of the WSPP (n=125) and WSDA AFP (n=1,124). The Survey Monkey form was displayed on WSDA’s website from January 2023-February 2023, and a total of 50 paper surveys were distributed during the WSID seminar. Although the survey reached 1000+ individuals, not every person the survey reached was a current or former pork handler in WA State. There were no requests for any surveys to be sent via mail.
A total of 30 responses were received:
Microsoft Forms - 2
Survey Monkey - 2
Paper - 26
Of the 30 responses received, 80% indicated that swine was raised for meat, including personal consumption.
The size of pens ranged from:
Small backyard pen of pigs (<50)- 16
Medium backyard pen of pigs (51-85)- 2
Large backyard pen of pigs (85-100)- 0
Commercial-size farm (111+)- 6
Ninety-three percent of respondents have never been an importer of pork meat or pork meat by-products, and the remaining 7% have imported pork products from Canada.
Twenty-three percent of farmers receive bulk commodity ingredients for use in animal feed regularly (monthly), all US-sourced, with no need for a FSVP.
Sixty percent of survey participants reported having knowledge of how ASF can spread through feed and feed ingredients, pork meat or pork meat by-products, while only 40% felt that ASF was a topic of concern for their farm or operation. In addition, 43% reported promoting heightened awareness and education surrounding ASF on their farm or operation.
Eighty-three percent of pork farmers in WA State are aware of the components of a biosecurity plan, while 57% reported having one implemented on their farms for swine.
Of the 57% (n=17) that reported having a biosecurity plan for pork, 73% of that population also reported having measures for animal feed safety included in their plans.
Eighty-four percent of the total participants responded they did not have knowledge of and access to the draft WA State FAD Response Plan document.
Conclusions
Several conclusions were drawn from the interviews and surveys. The survey results indicated that WA State pork farmers and producers are generally aware of the components of a biosecurity plan, and more than half of the survey participants indicated they have a plan implemented for their operation. A member of the WA State Vet’s office stated that the population of pork farmers, producers, and employees of pork farms are more concerned with current farm diseases such as Porcine Reproductive and Respiratory Syndrome, Porcine Endemic Diarrhea, and atrophic rhinitis. Less concern is given to FADs such as ASF that have not yet been identified on US soil. However, although less concern is given to FADs, based on the results from the study survey, most participants have knowledge surrounding how ASF can spread through feed and feed ingredients. Other conclusions are listed below:
The potential routes of entry into WA State for ASF include garbage feeding and incomplete biosecurity practices from imported feed ingredients.
There are only approximately 5,000 breeding pigs in WA State on approximately 400 farms as of 2022, with only two commercial farms and the rest being smaller backyard operations. As the number of farmers (if any) who are illegally participating in the practice of garbage feeding is unknown, small backyard herds in WA State present an increased risk of infection due to potential consumption of contaminated pork meat and bone meal.
Seventy-seven percent of survey participants stated they do not import animal feed bulk ingredients. Of the 23% that responded yes, the imports came from Canada, which is currently a non-infected ASF country.
According to the survey population, most pork farmers in WA State do not have knowledge of and/or access to the WA State FAD Response Plan document, indicating limited utilization and implementation of any suggestions for FAD biosecurity response.
Fifty-seven percent of the survey population reported having some type of biosecurity plan for their farms, with knowledge of how ASF can spread through feed and feed ingredients. However, prior to 2020, a representative from the WA State Vet’s office stated that most educational seminars and outreach meetings had previously been held in-person. There were some virtual meetings held during COVID, but due to lack of in-person meetings along with a slow return to these types of events, there was a period of time missed for opportunities to provide consistent outreach and biosecurity management updates to farmers.
Recommendations
The results and the conclusions drawn from the study in WA State give thought to some recommendations surrounding the subject of ASF virus introduction into the state. Topics for these recommendations include education and outreach, training and regulatory actions as follows:
Although this population of farmers may be difficult to reach, one recommendation is to continue stakeholder outreach and education efforts. Holding seminars, certification courses and informational meetings, and also including the youth population increases awareness that can be disseminated to all farmers. As more in-person meetings are being organized, additional informational campaigns about advanced biosecurity techniques and disease prevention and mitigation should be considered.
WA State should continue to advocate for USDA Center for Veterinary Biologics (CVB) and FDA to continue research into ASF developments, including spread via animal feed and feed ingredients, and vaccine trials and approvals. WSDA has planned tabletop exercises for ASF biosecurity set to occur within the agency, but there should be this same type of exercise performed with industry stakeholders and pork farmers. Hands-on training, in addition to educational seminars, will help to increase retention of information for use on both small and commercial-sized farms.
WSDA and other animal feed regulatory agencies in WA State should continue lobbying for the amendment to the SHPA to prohibit the feeding of garbage to swine. The garbage feeding amendment to the SHPA will help to minimize the risk of ASF spread through contaminated human food waste products that can be used in animal feed. In WA State, regulatory officials can help decrease risk of infection on small farms due to potential consumption of contaminated pork products while helping to push the federal government to implement a final rule prohibiting the feeding of garbage (as defined) to swine.
Acknowledgements
I would like to extend my sincerest thanks to:
My program manager, Ashlee-Rose Ferguson for recommending me for this fellowship and allowing me the support to participate in this great experience.
Doug Saunders, my IFPTI mentor, as well as Kathy Fedder, our second mentor, for the support, guidance, and understanding throughout the program, and to IFPTI for providing an invaluable education and professional experience.
My Fellows in Cohort XI. Through this experience, we have gained invaluable networking opportunities, friendships and partnerships for future collaborations.
WSDA, WSU, and the WSPP for assistance with survey distribution and bringing light to my research.
All of the survey participants.
And lastly, to my family for their never-ending support that kept me motivated throughout the duration of the program.
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Author Note
Vianca N. Philpotts, MS, Animal Feed Program Field Supervisor and PC Specialist,
WSDA
This research was conducted as part of the International Food Protection Training Institute’s Fellowship in Food Protection, Cohort XI.
Correspondence concerning this article should be addressed to:
Vianca N. Philpotts, Washington State Department of Agriculture
1111 Washington St SE Olympia, WA, 98504
Funding for the IFPTI Fellowship in Food Protection Program was made possible by the Association of Food and Drug Officials.