African Swine Fever: A Threat to Maryland Pork Production?

By Jacob Manley

Edited by Glenn T. Johnston

Michael Noble was a pig farmer in South Africa. He followed in the footsteps of several generations before him, keeping a small drove of pigs to support his family. One day, he noticed some of his pigs were acting lazier than usual and refused to eat. Thinking little of this, Michael carried on and continued to take care of his pigs as usual. Over the next several days, more of his drove began to behave the same way, and the first pigs to show signs had gotten significantly sicker. By the time Michael tried to stop the spread of whatever it was that was infecting his pigs, it was too late. Within weeks, every single pig on his farm was dead and his livelihood ruined. After testing the pigs to identify what had caused this tragedy, a culprit was identified: African Swine Fever (ASF).

ASF is a devastating disease of pigs caused by the African Swine Fever Virus. It has no known cure, treatment or vaccine. First discovered in 1921 in Kenya, ASF has since appeared in several regions around the globe. The first documented cases outside of Africa occurred in Europe in 1960, and since then, the disease has also spread to Russia, China, Latin America and the Caribbean. In regions affected by ASF, traditional pig-raising practices and a large wild boar population that can harbor the virus make controlling the disease difficult. In affected regions, the disease can devastate both domestic and wild swine populations.

African Swine Fever (ASF) warning and information poster. Source: Ohio Department of Agriculture, Division of Animal Health. Public health information used for educational purposes.

The disease itself has a very high mortality rate: nearly 100% of pigs that contract a severe infection of ASF die, and even less severe infections kill as many as 30-70%. Infected pigs may suffer high fever, internal bleeding, respiratory distress, and skin lesions before dying. The virus spreads quickly once it appears and can survive in the environment, making it difficult to contain. The disease can pass from pig to pig, whether wild or domestic, or through bedding or contaminated food. Between farms, the virus can spread to new regions in infected products, the migration of infected wild boar or even be carried on the shoes of visitors.

Because there is no vaccine or treatment for ASF, the primary means of control after detection is to cull infected and exposed pigs to prevent further spread. To avoid this kind of scenario in the US, security at our ports must stay on high alert, and best practices must always be followed on pork farms to protect American swine in case ASF slips past port safeguards. This security is maintained by the USDA’s Animal and Plant Health Inspection Service (APHIS) and Customs and Border Protection (CBP). These agencies use X-ray machines and their “Beagle Brigade” to identify illegal pork products in luggage and cargo as they enter the United States through all ports of entry. They prioritize surveillance of products from affected countries. By employing the beagles’ sense of smell instead of inspecting items by hand, more imports can be inspected in a shorter amount of time.

If this disease were to emerge in the United States, it would be difficult to eradicate, especially in southern regions, where it could persist in wild hog populations even if cleared from farms. It would be especially hard to remove from any of the 25 states that allow feeding recycled food scraps to pigs, as this can be a major source of contamination. According to an Iowa State study, impacts on American pork production would be catastrophic, costing the swine industry as much as $50 billion over 10 years.

To date, African Swine Fever has not entered the United States. The Port of Baltimore, which handles approximately 50 metric tons of declared pork and thousands of containers each month, represents one of many inspection points designed to prevent that outcome. At the national level, its impacts may be more severe. Maryland is not a large pork producer, with most of the state's domesticated pigs raised on smaller farms. This makes it harder for a single ASF outbreak to significantly reduce overall pork product output. Also, there is no established wild boar population in Maryland that could aid in the spread of the disease. These factors suggest that Maryland would likely experience less severe impacts than major pork-producing states if ASF were introduced.

Should the virus reach Maryland, losses will likely be isolated to individual farms with small populations of domesticated pigs. In that instance, it might be readily detected and managed successfully to prevent further spread, though losses could reach $1 million annually for the state if a severe outbreak were to happen.

Given the volume of global trade, contingency planning assumes that introduction is possible despite preventive efforts. Because it is impossible to inspect every item entering U.S. ports, continued vigilance, farm biosecurity, and preparedness planning remain essential.