"The exact cause of this breach is unclear but is most likely due to multiple factors, including interruptions in sterile fly production due to the COVID-19 pandemic and illegal cattle imports, as well as the challenges involved in surveillance of the (Darien) gap’s difficult geography."

https://asm.org/articles/2025/september/new-word-screwworm-r...

There's currently only one plant in Panama running the sterile fly program, but both Mexico and the US are opening new plants to handle the issue.

"The U.S. Department of Agriculture is constructing a new $750 million facility nearby to breed sterile flies, though U.S. Agriculture Secretary Brooke Rollins said it won’t be completed until late 2027. In the meantime, the agency is investing $21 million to transform a fruit fly breeding center in far southern Mexico into a screwworm fly production site, with operations set to begin this summer."

https://www.statesman.com/news/article/texas-possible-new-wo...