Preparing for African Swine Fever

By Jeff Wiegert, PhD, Swine Extension Specialist, Texas A&M AgriLife Extension

African Swine Fever (ASF) is a disease of swine endemic to the wild pig species of sub-Saharan Africa, such as bush pigs and warthogs. The virus that causes ASF is deadly in domestic swine but does not infect humans or other animals. Symptoms of ASF in infected pigs include fever, anorexia, weakness, blotchy skin, diarrhea and vomiting, difficulty breathing, and spontaneous death, and certain strains of the virus can result in acute outbreaks with near 100% mortality.

The virus primarily spreads between pigs through direct contact with infected animals, interaction with contaminated fomite (e.g., boots, clothing, or vehicles), ingestion of contaminated pig tissue or pork products, and bites from certain species of ticks known to carry the virus. Despite ongoing efforts, there is currently no commercially available vaccine or treatment for ASF. Moreover, the virus is highly resilient, and can remain infectious in suitable environments for months or longer, making it extremely challenging to control or eradicate. Wild pig populations are known to harbor the ASF virus and spread it to domestic pig farms. In Texas, feral pigs outnumber domestic swine at least 3:1. The virus can survive on fresh, cured, and frozen pork, making human transportation of food products a common mechanism of disease transmission, particularly over long distances.

Although ASF is not currently present in the United States, it is spreading worldwide and causing havoc wherever it appears. Over the past decade, the virus has emerged in Asia, Europe, and the Caribbean, resulting in severe consequences for pig producers. To control the spread of the disease in these countries, producers have been forced to resort to mass culling of infected and at-risk animals, leading to significant financial hardships due to limited pig supply and elevated production costs associated with farm biosecurity, disease surveillance, and animal health, mortality, and disposal expenses. Unfortunately, these economic conditions have disproportionately affected smaller-scale swine producers. Additionally, because the ASF virus survives in pork products, ASF infection prevents affected countries from exporting their products internationally, further burdening local pork markets and limiting producer revenue.

The US would likely experience similar costs to pig health and production following an ASF outbreak. Indeed, the loss of export opportunities would pose a substantial economic challenge to the US pork industry, as greater than 25% of domestically raised pork is currently consumed internationally. For these reasons, the USDA classifies ASF as a Foreign Animal Disease, meaning that the virus will not be tolerated to exist in the United States, should it arrive.

While ASF is not currently present in the US, it is essential to consider the possibility of its arrival and to prepare accordingly. Of course, the ideal scenario will be to keep ASF out of Texas and the US indefinitely. However, this may not be realistic, and we need to shift our mindset to address the inevitable arrival of ASF. Understanding the immediate impact of ASF on US pork production and implementing the Secure Pork Supply plan to enhance swine farm biosecurity are the first steps in establishing an ASF readiness plan.

National Response to African Swine Fever Infection
The immediate goal following confirmation of an ASF outbreak will be to identify the extent of the infection, control the outbreak, and contain the virus from further spread. Initially, a federal “Stop Movement” rule will be enforced, prohibiting the transportation of live swine and semen for at least 72 hours. During this time, no pigs will be allowed on the road, and ongoing shipments will need to return to the farm of origin, proceed to the destination, or identify and utilize an intermediary stopover. This temporary halt will help determine the extent of viral presence and prevent unintended transmission across the country. The duration of the standstill will depend on the severity of the outbreak, and it should be emphasized that 72 hours is the proposed minimum duration, not the maximum. A longer travel ban is a strong possibility.

Farms with confirmed ASF infection will be quarantined, and pigs will be euthanized as humanely and efficiently as possible to eliminate the virus. Buffer zones and control areas will then be established around infected farm premises (Figure 1), with the size of these boundaries determined by the density and interconnectedness of pig farms in the area. If numerous farms are linked by the movement of pigs, people, or shared equipment, a larger surveillance boundary will be established. Farms operating within this perimeter will undergo intensive monitoring and will require permits for pig movement.

Clearly, an ASF outbreak in the US would be devastating. Economists estimate that it could result in nearly $80 billion in total costs to US agriculture (Carriquiry, M., A. Elobeid, and D. Hayes. 2023. Working Paper 23-WP 650. Center for Agricultural and Rural Development, Iowa State University). Texas producers should be aware that we are likely to face challenges similar to those being experienced in Asia, Europe, and the Caribbean. However, we have the distinct advantage of being able to begin preparations now to mitigate the impact and expedite virus eradication

Enhance Farm Biosecurity with the Secure Pork Supply Plan
The Secure Pork Supply (SPS) plan is a readiness plan designed to maintain business continuity in the event of a Foreign Animal Disease outbreak. It consists of comprehensive guidelines and procedures developed by national health officials and industry stakeholders to ensure continuity of pork production by enabling the safe movement of pigs while minimizing the risk of disease spread. Implementing the SPS plan may enable farms located within the control area surrounding an ASF-infected premise to more quickly obtain permits for moving pigs off the farm.

In Texas, the Texas Animal Health Commission (TAHC) is responsible for coordinating and approving SPS plans. Developing a SPS plan for your swine farm is not a terribly difficult process. In fact, students in my Swine Production class at Texas A&M University can typically write an SPS plan for the TAMU Swine Unit in one lab period (less than 2 hours).

The SPS plan is multifaceted but involves three key components:

  1. Obtain a Premise ID Number (PIN)
    • A Premise ID Number (PIN) is a numerical code assigned to a farm by the TAHC. In the event of an ASF outbreak, swine farms will be identified by their PIN, and all movement permits and diagnostic sample submissions to veterinary labs will be tied to this PIN. The PIN must be associated with the geographic location of the animals; farms with pigs in multiple locations will need a PIN for each site. To obtain a PIN, contact the TAHC Animal Disease Traceability office at animal_id@tahc.texas.gov or (512)-719-0733.
  1. Maintain Detailed Movement Records
    • Movement records of pigs, people, vehicles, and equipment onto and off of the farm will aid virus traceability in the initial aftermath of the outbreak. These records will also be required when applying for pig movement permits. Digital record storage is preferred (for example, in a Microsoft Excel file or Google Sheet) as this will facilitate faster information transfer to animal health officials. Movement record templates are available online at the Secure Pork Supply website: https://www.securepork.org/.
    • Producers are strongly encouraged to create an account through AgView, a free opt-in technology from the National Pork Board that provides disease status updates and facilitates sharing of pig movement data with state animal health officials. More information on AgView can be found online at: https://www.agview.com/
  1. Develop Your Farm’s Enhanced Biosecurity Plan
    • The Enhanced Biosecurity Plan is a written document outlining the farm’s biosecurity practices. Implementing the recommended biosecurity measures described in this plan may lessen the risk of ASF infection on your operation. Furthermore, farms that have Enhanced Biosecurity Plans approved by TAHC will be better positioned to quickly obtain movement permits and continue normal business operations. Notable components of the Enhanced Biosecurity Plans include designating a farm biosecurity manager (usually the farm owner or manager), outlining vehicle movement pathways on the premise (including feed trucks and site visitors), and establishing physical barriers around the farm (such as gates or perimeter fences). These physical barriers will be particularly valuable in Texas to prevent direct contact with potentially infected feral pigs. To be sure, a perimeter fence around the farm may not be a foolproof deterrent against feral pigs, but it is greatly preferable to having no protection at all against wild pig spread of ASF. Inspecting the fence early and often for signs of damage or breaches can also direct feral pig removal efforts.
    • Assistance is available to complete the Enhanced Biosecurity Plan. Veterinarians at North Carolina State University have developed the Rapid Access Biosecurity app (RABapp) to standardize biosecurity templates, assist producers in creating site-specific plans, and submit the paperwork in the appropriate format to TAHC. All producer data used in plan development remains confidential and visible only to authorized staff, veterinarians, and TAHC officials. Texas swine producers are highly encouraged to utilize the RABapp resource. To begin developing your Enhanced Biosecurity Plan, contact Dr. Gustavo Machado at machado-lab@ncsu.edu or (919) 513-0781.

Conclusions
African Swine Fever has the potential to devastate pork production in Texas and US, and we must prepare for this challenge now. The Secure Pork Supply plan is an excellent first step to enhance farm biosecurity and ensure seamless business operations in the event of an ASF outbreak. I understand that this responsibility is exceptional, unique, and demanding. Please do not hesitate to contact me with any questions or concerns: jeffrey.wiegert@ag.tamu.edu.

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