USDA Detects First U.S. Gusano Barrenador Case in Texas Calf
The USDA detected the first U.S. animal case of gusano barrenador in a 3-week-old calf in Zavala County, Texas. Inspectors found larvae in the calf’s umbilical area during a bovine inspection.
Zavala County inspection
The Servicio de Inspección de Sanidad Animal y Vegetal, part of the USDA, said the Zavala County case was the only one recorded in the United States at the time of the report. The calf was the first animal in the country identified with the parasite, and Texas authorities said containment would follow the established response manual after the detection.
What gusano barrenador can do
Gusano barrenador comes from the larvae of the fly Cochliomyia hominivorax. It can affect cattle, pigs, dogs, cats, wildlife, and humans when the fly lays eggs in open wounds or natural body openings. After hatching, the larvae feed on living tissue and can cause tunnel-like damage, expanding lesions, intense pain, secondary bacterial infections, and serious tissue damage. If not treated in time, the infestation can be lethal.
USDA warning to residents
The USDA said its analysis indicated the parasite would reach the southern United States, which is why sanitary protocols were already in place before the Texas case was identified. The agency asked residents to check pets and livestock for wounds that ooze or enlarge, signs of discomfort, and worms in body openings such as the nose, ears, genitals, or the belly button of newborn animals.
From Panama to Texas
The outbreak in northern Latin America began in July 2023 on the Panama-Costa Rica border and reached Chiapas in southern Mexico in November 2024 before the U.S. case was detected. Charles Coquerel, a French entomologist, was the first to identify the parasite on Isla del Diablo in French Guiana, a reminder that the same organism now appearing in Texas had already pushed north through several animal-health borders.
For ranchers and pet owners in Texas, the practical step is immediate inspection, especially around newborn animals and any wound that could attract the fly. The Texas case gives local veterinarians and livestock owners a specific warning sign to watch for: larvae in the belly button of a calf or other body openings, not just obvious skin wounds.
