The Newworld Screwworm (Cochliomyia hominivorax) has resurfaced across Central America, threatening livestock and occasionally humans. Unlike typical flies, it deposits eggs in living tissue, and maggots consume the host from the inside. Historic eradication relied on the sterile insect technique, a radiation‑based method that sterilized male flies to break the reproductive cycle to protect the agricultural economy worldwide.

In the 1930s researchers Raymond Bushland and Edward Knipling proved the approach on Curaçao, wiping out the pest in seven weeks. Over the following decades the program pushed the flies northward, eliminating them from the United States in the 1960s and from Mexico and Belize by the 1980s, with Panama serving as a narrow containment corridor maintained by the binational COPEG commission and sustained international funding.

The barrier collapsed around 2022, with Panama reporting 6,500 cases in 2023 and infestations spreading into Mexico. Officials cite Covid‑related supply chain disruptions that halted sterile‑fly production, but entomologists argue unchecked livestock migration carried the insects north. The program costs roughly $15 million annually; reviving it will require scaling SIT output in Mexico and Central America and tightening herd movement controls and prevent further economic loss.