The U.S. Department of Agriculture has confirmed New World screwworm in a goat in Sutton County, Texas, raising the total number of confirmed U.S. animal cases to 42 since the outbreak began in early June. Only 10 of those cases remain active.
That second number is the more useful one, and it marks a real change. When MedicalDaily reported the count at 25 cases in late June, just three had been closed out. Today roughly three-quarters of confirmed cases are classified as inactive, meaning treatment finished and wounds healed, or the animal died and the carcass was managed to prevent further spread.
The geographic footprint has also stayed narrow. Of the 42 confirmed cases, all but one are in Texas. The single exception remains in New Mexico. There are still no confirmed human infections acquired in the United States.
What Active and Inactive Actually Mean
The distinction matters because case totals alone say almost nothing about containment.
USDA APHIS defines active cases as those "that involve ongoing disease mitigation efforts," including treatment and wound management until all wounds have healed. Inactive cases are those where mitigation is no longer required. The agency's public dashboard tracks individual animal cases by county, state, species, and confirmation date, alongside fly traps that have caught at least one wild screwworm.
A running total that rises while the active count stays low describes a response that is finding and closing infestations. A rising active count would describe something else. Right now the ratio is moving in the direction animal health officials want, and reporting the total in isolation would misrepresent the trajectory.
That said, confirmed cases are not the same as total infestations. Detection depends on producers noticing wounds and reporting them, and coverage across rangeland is uneven.
Why Each Detection Is Treated as Containment-Critical
New World screwworm is not an ordinary parasite. The larvae of Cochliomyia hominivorax feed exclusively on living tissue, which is what separates it from flies that consume dead flesh.
According to the CDC, a female fly is drawn to open wounds and to body openings including the nose, mouth, eyes, genitals, and the umbilical area of newborn animals. A wound as small as a tick bite can attract her. One female can lay 200 to 300 eggs at a time and up to 3,000 across a lifespan of 10 to 30 days. The larvae hatch and burrow into healthy tissue, tearing it with sharp mouth hooks, and the wound grows larger and deeper as more larvae feed. Secondary bacterial infection is common.
The United States eradicated the parasite in 1966 using the sterile insect technique, releasing sterilized male flies to collapse wild reproduction. That program was one of the most successful pest eradication efforts in American history, and its integrity is the reason a single confirmed case triggers a full response rather than routine monitoring.
The federal response has escalated steadily. On July 15, the FDA issued its 11th Emergency Use Authorization against screwworm, covering ivermectin oral solution for short-term prevention in horses when given within 24 hours of birth or during initial wound care. That authorization is prescription-only, applies to horses alone, and covers prevention rather than treatment of existing infestations. Earlier authorizations have covered dogs, cats, cattle, small ruminants, and captive exotic species.
The Human Health Question, Answered Precisely
Screwworm can infest people. It rarely does, and no locally acquired human case has been confirmed in the current U.S. outbreak.
The one U.S. human case in this cycle was travel-associated, identified in a Maryland resident returning from El Salvador in August 2025. Federal health officials described the risk to U.S. public health as very low at that time, and that assessment has not changed with the current animal detections.
The people at elevated risk are narrow and identifiable: those with open sores or wounds that are not kept clean and covered, people who work closely with livestock or wildlife in areas with confirmed activity, people who are unhoused or sleeping outdoors in affected areas, and people with weakened immune systems or chronic non-healing wounds, including some patients with diabetes or peripheral vascular disease.
There is no medication that treats human screwworm myiasis. Clinical management, per CDC guidance for providers, involves physical removal of the larvae, preservation of specimens in 70 percent alcohol, and submission to CDC for identification. That is a procedure for a clinician, not something to attempt at home.
The warning sign is a skin lesion or wound that fails to heal and worsens over time, sometimes with a sensation of movement or a foul odor. Anyone with that presentation who lives in or has traveled to an affected area should see a clinician promptly.
What Households and Animal Owners in the Zone Should Do
For residents of the quarantine counties, the practical guidance is wound care.
Keep any open wound on a person, a pet, or livestock clean and covered. Check pets after time outdoors, particularly around the ears, nose, and any cut or surgical site. Maintain routine flea and tick control, since preventing bites reduces the small wounds that attract screwworm flies. Report any suspected animal case to a veterinarian or the Texas Animal Health Commission immediately.
Two things do not need doing. There is no food safety risk: USDA has confirmed that screwworm does not infest meat, produce, or any food product. And there is no reason for households outside the quarantine area to alter routines.
Sterile fly releases continue as the primary long-term strategy, and full eradication capacity is expected to take 18 to 24 months. USDA is expected to update the public dashboard as new cases are confirmed and as active cases close out.
The newest confirmed case is a goat in Sutton County, and the running total is 42. The people most affected are livestock producers and animal owners inside the Texas quarantine zone. The most reasonable action for households is clean, covered wounds and prompt veterinary reporting. The central uncertainty is how many infestations remain undetected on rangeland between confirmed cases.
Related MedicalDaily.com Coverage
New World Screwworm Has Now Reached 25 Cases in Texas: What Dog and Cat Owners Need to Know
CDC Activates Emergency Operations Center Following New World Screwworm Detection in Texas
Developing Story Timeline
July 27, 2026: USDA APHIS confirms New World screwworm in a goat in Sutton County, Texas, bringing the U.S. total to 42 cases since early June, with 10 active.
July 15, 2026: FDA issues its 11th Emergency Use Authorization against screwworm, covering ivermectin oral solution for short-term prevention in horses.
June 25, 2026: Case total reaches 25, with three cases classified as inactive.
June 3, 2026: USDA confirms the first U.S. animal case in nearly 60 years, a three-week-old calf in Zavala County, Texas.
Frequently Asked Questions
How many screwworm cases have been confirmed in the United States? Forty-two confirmed animal cases since early June. All but one are in Texas; the other is in New Mexico. Ten cases remain active.
What does an inactive case mean? USDA APHIS classifies a case as inactive when disease mitigation is no longer required, either because the animal recovered with wounds healed, or because a deceased animal's carcass was managed to prevent spread.
Have any people been infected in this outbreak? No locally acquired human case has been confirmed. One travel-associated case was identified in a Maryland resident returning from El Salvador in 2025, and federal officials described U.S. public health risk as very low.
Who is at higher risk of human infestation? People with open or non-healing wounds, those working closely with livestock or wildlife in affected areas, people sleeping outdoors, and people with weakened immune systems.
Is the food supply affected? No. USDA has confirmed that New World screwworm does not infest meat, fruits, vegetables, or any food product.
How should pet owners in the quarantine zone respond? Keep wounds clean and covered, inspect pets after outdoor time with attention to ears, nose, and any cut or surgical site, maintain flea and tick control, and contact a veterinarian about any wound that worsens.
What should someone do about a wound that will not heal? See a clinician promptly, particularly after travel to an affected area. There is no medication that treats screwworm myiasis in humans; treatment requires physical removal of larvae by a healthcare provider.
