S&T Proactively Preparing for African Swine Fever

Going through the horrific trials and tribulations of a natural disaster, terrorist attack, or even a global pandemic has a dimly shining but very real silver lining. It makes us better prepared for the inevitable next time. It builds resilience.

COVID-19 is still threatening the health and wellbeing of our loved ones and our very way of life, but it has taught us a lot about what it takes to make it through a large scale, prolonged public health emergency. We have seen firsthand the critical importance of information sharing and teamwork. A shining example: Master Question Lists (MQL). These documents consolidate the most relevant research findings—organizing our collective knowledge to help facilitate a coordinated response effort across not only federal, state, and local government, but also international partners. The Department of Homeland Security (DHS) Science and Technology Directorate (S&T) has been maintaining an MQL for COVID-19 since March 2020, based on a similar product developed in 2014 in response to the 2014-2015 West African Ebola outbreak.

Consolidating research and the known facts, and highlighting what we still need to know to implement an effective response, helps guide researchers and responders alike in daily operations and future studies. Until now, S&T’s MQLs were focused on diseases that impact human health, but there are other diseases of consequence that, while not contagious to humans, may severely impact our livestock, and thus our food supply and economy. With up to a 100 percent mortality rate in pigs, African Swine Fever (ASF), which continues to spread in Asia, Europe, and Africa, is still cause for grave concern here in the United States. That’s why S&T is being proactive and meeting this emerging threat now with a newly published ASF MQL.

A mass outbreak of ASF in our nation’s domestic swine population—and any outbreak of ASF has strong potential to become widespread due to its high transmissibility—could land a powerful blow to the U.S. economy. Our nation is the largest pork exporter in the world. More than 115 million U.S. hogs go to market each year with a value of $24 billion. An ASF outbreak wouldn’t just mean lost revenue from sales, though. It threatens livestock as well as livelihoods. ASF in the United States would cost additional billions of dollars to control the spread and could hobble our agricultural infrastructure. Though it originated in Africa, ASF has wiped out an estimated 40 percent of China’s swine population since the first confirmed outbreaks there in 2018. The United States has been spared so far, but with the disease expanding to over 50 countries, it may be a matter of time before it reaches our shores and infiltrates our livestock.

At the forefront of the battle against ASF is S&T’s Plum Island Animal Disease Center (PIADC), which formed a task force aimed at interagency coordination of countermeasure (vaccines, diagnostics, disinfectants) research. PIADC is working closely with the U.S. Department of Agriculture and other federal agencies, industry, academia, and domestic and international partners to study the ASF virus. Researchers seek to understand prevention, transmission, impacts, and potential countermeasures. The ASF MQL is an important resource to ensure effective collaboration, as it will help track what we know and focus on the important knowledge gaps that remain.

Key takeaways from the premiere edition of the ASF MQL include:

• Infected domestic swine can pass the disease on to an average of 2.8 other pigs.
• ASF can spread between domestic or feral swine by direct or indirect contact, as well as through vectors such as soft-bodied ticks.
• Mortality rates can reach 100 percent in acute infections and range from 30% - 70% in subacute infections.
• Clinical signs generally occur within four days, though it varies widely (1-28 days) depending on exposure dose/route and ASF virus strain.
• We need to better understand the risk for introduction of ASF into the U.S feral swine population through various routes, including soft ticks typically found in the U.S.

The ASF MQL, produced by S&T’s Hazard Awareness & Characterization Technology Center, in collaboration with PIADC and the Probabilistic Analysis for National Threats Hazards and Risks (PANTHR) program, will be regularly updated as new information becomes available. It’s an important preparedness resource and represents a whole-of-government approach and proactive posture as we address this emerging global threat. It also signifies a continued commitment to remain on the cutting edge of science and technology in the pursuit of national security. Check back for updates as S&T continues to apply lessons learned to the ASF threat.