The New World screwworm, a parasitic fly whose larvae feed on the living tissue of warm-blooded animals, has re-emerged in Texas, marking the first detection in the U.S. since its eradication in 1966. As of July 1st, there are 29 confirmed cases in the U.S., with 28 in Texas (22 active and 6 inactive) and one of the new cases in Pecos County being the first confirmed dog infection. This outbreak represents a significant setback for farm health officials who aimed to prevent the spread from Mexico.
In response, the Texas Animal Health Commission has quarantined 21 counties across West, South, and Central Texas, restricting animal movement to curb the spread. U.S. Agriculture Secretary Brooke Rollins has announced a substantial federal investment of over $1 billion to eradicate the screwworm, including $1.3 billion in emergency funding. The USDA has also ramped up its staffing, adding over 100 full-time employees to work on the screwworm issue in the past 15 months.
The primary strategy for eradication involves releasing sterile male screwworms to disrupt reproduction. While experts estimate 500 million sterile flies are needed weekly, the U.S. is currently producing about 100 million per week from a facility in Panama. A new facility in Metapa, Mexico, is expected to come online, eventually adding another 100 million flies per week, with an initial output of approximately 9 million by the end of July. A domestic facility at Moore Air Base in Edinburg, projected for late 2027, aims to produce an additional 100 million, with a capacity for 300 million sterile flies weekly. Rollins noted that current production is sufficient to slow the spread, but not eradicate it, emphasizing the need for more flies.
The USDA has also invested in new technologies, including the "Novofly" project, a genetically engineered solution to produce only male flies, which would significantly reduce the required number of sterile flies. They have also launched a $100 million grant challenge for creative ideas and technologies, such as new trapping methods and developing male sterile flies with a hyperactive sex drive. Political debate surrounds the outbreak, with Rollins attributing the re-emergence partly to border policies, while Democrats point to significant USDA staff cuts in early 2025 as a hindering factor.
The outbreak has been described as an ominous development for the embattled livestock sector. The quarantines remain in effect until lifted by the commission, and the overall effort to contain and eradicate the screwworm is anticipated to be a years-long fight, requiring continuous vigilance and substantial resources.
