The screwworms have reemerged in the US after decades of eradication, with five confirmed cases reported—four in Texas calves and one in a dog. These flesh-eating fly larvae pose a significant threat to livestock, with the USDA estimating potential costs of $732 million annually for Texas producers if containment fails. The flies were previously eradicated using a Sterile Fly Technique but breached containment barriers around 2022.

While human cases remain less frequent, they can be severe and potentially fatal. Recent cases from Central America show screwworm larvae causing painful wounds that can progress to deeper tissues, with risks of secondary infection, sepsis, and mortality. In one documented case, a 15-year-old girl required removal of full-thickness scalp tissue after larvae burrowed near her brain.

The economic impact extends beyond agriculture, with potential $1.8 billion in costs to the Texas economy. The flies can exploit any wound as small as a tick bite or enter through orifices, making prevention challenging. Health officials urge vigilance for travelers returning from affected areas and prompt medical attention for unusual wounds, especially in vulnerable populations with compromised immune systems.