A confirmed New World screwworm case in a three-week-old calf in Zavala County has put Texas animal-health and public-health agencies on alert, even though the official notices reviewed did not report a Sherman-area or North Texas detection.
The Texas Animal Health Commission said it received confirmation on June 3, 2026, after a sample from a calf with an umbilical lesion was identified as New World screwworm by the National Veterinary Services Laboratories in Ames, Iowa. TAHC said there were no further confirmed detections in animals in Texas at the time of its notice.
USDA's Animal and Plant Health Inspection Service also confirmed the detection in a bovine in Zavala County. Federal officials said the affected animal was a three-week-old calf and that larvae were identified in its umbilical area.
What Sherman readers need to know
For Sherman residents, the important point is not that a local case has been announced; it has not been in the official notices reviewed. The point is that New World screwworm can affect warm-blooded animals and that quick reporting is part of the state response.
New World screwworm is a parasitic fly, not a worm. According to CDC and Texas DSHS guidance, female flies lay eggs on or near open wounds or body openings such as the eyes, ears, nose, mouth, genitals or the navel of newborn animals. When the eggs hatch, larvae burrow into living tissue and feed there.
DSHS says there is no human-to-human transmission of New World screwworm infestation. The infestation requires the fly life cycle, beginning with eggs laid by a female fly.
Warning signs in people and animals
DSHS said people should seek immediate medical care if they notice a suspicious lesion or believe they may have contracted screwworm. The agency said providers should consider New World screwworm in patients who have traveled in areas with animal or human cases and who have a painful, foul-smelling wound containing visible larvae, or a deep wound with extensive tissue damage.
Anyone who sees or feels larvae in a wound should cover the wound and contact a health care provider immediately, according to DSHS. The agency warns people not to try to remove or dispose of eggs or larvae themselves because improper removal can cause further tissue damage and mishandled live larvae could create a risk of spread.
For animals, DSHS says signs can include irritation or discomfort, the smell of decay around a wound or body opening, open wounds or sores, and visible larvae. Pet and livestock owners who suspect an infestation should contact a veterinarian quickly. Livestock and pet cases should be reported to TAHC.