SEAN EASTMAN DVM, Clemson Livestock Poultry Health
CHRISTOPHER LeMASTER JR, Clemson Extension Livestock & Forages
USDA has now confirmed a case of New World Screwworm in a calf near La Pryor, Texas, roughly 50 miles from the border. Recent warnings have renewed attention on the New World screwworm, a pest with serious implications for livestock, wildlife, and even pets. While not currently established in our region, its proximity—and history in the southeastern U.S.—make awareness especially important.
For the beef industry alone, the potential economic impact is substantial. Estimates suggest losses could reach into the billions of dollars if the New World screwworm were to re-establish in the U.S. This threat also extends beyond cattle, affecting other livestock, wildlife, and even pets—broadening the economic and ecological impact.
What makes the screwworm particularly concerning is its life cycle. Adult flies are drawn to open wounds and lay eggs, and the larvae then feed on living tissue. This means even minor injuries—dehorning, castration, puncture wounds, or something as small as a tick bite—can create an entry point. Routine inspection of any wound is critical.
Right now, the priority is recognition and reporting. We are in a surveillance phase, and early detection is key to control. If you suspect a case, report it. Doing so does not put an “x” on your back—it’s how we protect the industry as a whole.
The good news is we’ve dealt with this before. Screwworm was once endemic in the U.S. but was eradicated in the late 1950s through sterile fly production, which prevented reproduction and proved highly effective. Today, we have even more tools available, including expanded sterile fly capacity and additional treatment options with more approved labels.
For now, stay aware and stay vigilant. Regularly check animals, monitor any wounds closely, and report anything suspicious.
- If you suspect a case in a person: Report immediately to South Carolina Department of Public Health via the regional epidemiology office or the statewide emergency number (1-888-847-0902).
- If case is in deer and wildlife: S.C. Department of Natural Resources, Wildlife and Freshwater Fisheries Division, (803) 734-3886
- If suspected in domestic animals: Clemson University Livestock-Poultry Health, (803) 788-2260
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