SPOTLIGHT By Kenneth E. Nusbaum, D.V.M., Ph.D.
Is African Swine Fever an Emerging
Threat to the U.S. Pork Supply?
Once upon a time, livestock in this country were protected by two giants: the Atlantic Ocean and the Pacific Ocean. The slow rate of travel allowed the death or discovery of
infected animals, and once those shipments
arrived on these shores, strict import rules
and zero tolerance prevented introduction of
diseases once referred to as “exotic” or “foreign
animal” diseases. These diseases are now called
Livestock in the U.S. have no genetic experience with—and
therefore no resistance to—such infections, which can ruin
production or cause death among all infected animals. What’s
more, the U.S. has no vaccine stocks in reserve for these diseases. Today, global movements of livestock, game, or bush
meat, as well as people, create new threats to animal industry
in the U.S. (Table 1). State and federal governments struggle
to control these incursions at the cost of millions of animals
depopulated or killed.
One such disease is African swine fever
(ASF), once largely found in Africa, which has
become a chronic feature of swine agriculture
in Eastern Europe and China. Given the large
population of feral swine in North America,
ASF may pose a significant threat to U.S.
pork production. Ticks can be a vector for the
ASF virus, and climate change enables more
ticks to survive seasonal cycles and carry and
spread infectious disease (Table 2).
The virus can persist for long periods in uncooked pig
products and be transmitted to swine when they eat food
waste. Families traveling internationally may bring traditional
food gifts for important festivals such as Tet (the Asian New
Year), which enables the spread of infectious agents and may
introduce new species of ticks as potential vectors in the U.S.
(Table 3). The introduction of ASF in the U.S. would stop
all export of pork and have profound, deleterious effects on