With those sterile

flies and that very narrow gap of land as the principal place of control, we were able to keep the flies from coming back up sort of through Central America, Mexico, and the United States.

And so we had, as the U.S. government, had partnership agreements with Panamanian folks and the Mexican folks who were responsible for breeding flies.

hundreds of millions, billions of flies, and doing controlled releases continuously throughout the year in order to make sure that there are always sterile male flies available and being released whenever there was a chance that there was a viable female in the area.

And we held that for a number of decades.

That broke down.

in part because of some destabilization that happened in economies in South America, which caused people to migrate north and bring with them their animals and cross that Darien Gap.

I mean, how are they going to know?