Except for occasional reintroductions, primarily in imported dogs and horses, the screwworm has been eradicated in the U.S. Eradication started in the 1950s with the joint vision of ranchers working with USDA in a multidecade effort that included Mexico and Central America. This fascinating article sheds light on what it took to get rid of screwworms. As importantly, it focuses on the relentless fight to keep the parasite contained.
Source: The Atlantic, May 26, 2020. Link. . . . the USDA to this day maintains an international screwworm barrier along the Panama-Colombia border. . . . Every week, planes drop 14.7 million sterilized screwworms over the rainforest that divides the two countries. A screwworm-rearing plant operates 24/7 in Panama. Inspectors cover thousands of square miles by motorcycle, boat and horseback, searching for stray screwworms infections north of the border.
The screwworm program costs $15 million a year, a small fraction of the $796 million a year that it saves American farmers.
INSIGHTS: It is one thing to contain a pest or disease. Keeping it contained is an entirely separate effort as this article explains.