The USDA-APHIS is negotiating with the World Organization for Animal Health (OIE) to designate Puerto Rico and the Virgin Islands as separate regions from the U.S. mainland based on spatial epidemiology. This action is in anticipation of possible extension of African swine fever (ASF) from the Dominican Republic (and inevitably Haiti), to other nations in the Caribbean that may include the U.S. territories of Puerto Rico and the Virgin Isles. If a distinction is made on the basis of regionalization, the U.S. mainland would maintain an OIE status of freedom from ASF. The infection is currently prevalent in Eastern Europe, Baltic nations and Germany in addition to sub-Saharan Africa and many Asian countries including China. The disease once introduced to an area cannot be controlled without an effective vaccine especially in the presence of feral hogs. Biosecurity may prevent introduction into suitably constructed and operated hog integrations but backyard, subsistence and small operations relying on traders will remain vulnerable to infection.
The USDA stated, "in the event of a detection, we would quickly work with trading partners to regionalize Puerto Rico from the U.S. mainland and to show mitigations that are in place to prevent disease spread from Puerto Rico to the U.S. mainland".