Screw worm infections would be easy to spot with proper inspections. No need for genetically engineered sterile screw flies which may or may not actually be sterile and could increase problems if released. Bill Gates genetically engineered mosquitoes to combat malaria carrying mosquitoes and release them over population which cause an over population of mosquitoes and a spike in malaria cases. What did they do about that spray toxic pesticides over populations to get rid of the mosquitoes. They way pesticides work have a toxic effect on all animals including humans too. I see this attempt with screw flies being no different.
https://thepostmillennial.com/usda-set-to-reopen-mexican-beef-imports-despite-concerns-over-flesh-eating-screwworm-infestation?utm_campaign=64466