Why It Matters
Southern states face a potential livestock crisis as the New World screwworm—a flesh-eating parasite eradicated from the United States in the 1960s—spreads through Mexico and approaches the U.S. border. Federal officials have already banned live cattle imports from Mexico, compounding a domestic beef shortage that has driven ground beef prices to record highs. State veterinarians and ranchers are implementing emergency monitoring protocols as federal authorities prepare a $750 million facility to produce sterilized flies for containment efforts.
What Happened
The screwworm fly has been detected within 100 miles of the U.S.-Mexico border, prompting coordinated action from state and federal agricultural agencies. The parasite’s larvae burrow into living tissue through wounds or body openings, causing severe damage to livestock, pets, wildlife, and in rare cases, humans. New Mexico launched an information website last week to help ranchers identify infestations and report suspected cases. The state has conducted approximately 30 tests so far, all returning negative results.
The U.S. Department of Agriculture banned imports of live Mexican cattle in response to the threat. That policy has disrupted normal market operations, as Mexican cattle traditionally occupy American pastures and feedlots before slaughter. Federal regulators have approved emergency use of several preventive medications, including ivermectin, though state officials caution against overuse to avoid resistance.
By the Numbers
Ground beef now averages $6.90 per pound nationwide, representing a 77 percent increase from $3.89 in January 2020. American cattle herds have fallen to their smallest size in 75 years following years of drought and elevated operating costs. The federal government is constructing a $750 million facility dedicated to breeding sterile screwworm flies for population control. Cases have been confirmed within 100 miles of the border, and New Mexico has distributed testing kits to every county extension office.
Zoom Out
The original screwworm eradication campaign in the 1960s took more than a decade of coordinated work between American and Mexican officials. Livestock industries across southern states now face similar challenges, compounded by tight beef supplies and strong consumer demand. The current crisis mirrors broader agricultural pressures affecting meat production nationwide, including climate impacts on grazing land and rising input costs that have forced ranchers to reduce herd sizes.
What’s Next
Federal authorities plan to deploy sterile male flies that will mate with wild females, producing non-viable eggs to suppress the parasite population. Ranchers must monitor newborns closely for exposed umbilical cords and may need to modify branding and tagging practices that create entry wounds. State veterinarian Dr. Samantha Holeck of the New Mexico Livestock Board said officials expect the parasite will enter U.S. territory despite prevention efforts. Agricultural experts anticipate a successful re-eradication campaign but warn the timeline remains uncertain and will require sustained cooperation across multiple agencies and borders.