Edwards County – New World screwworm detections surged across Central and West Texas this week, with Texas still the only U.S. state reporting active cases. The Texas Animal Health Commission expanded quarantine zones across 18 counties as USDA confirmed six additional cases o
For the third morning in a row, Texas animal owners and veterinarians have had to ask the same hard question: what if the next wound is the one that invites the screwworm?
On Wednesday, June 24, the U.S. Department of Agriculture confirmed six new New World screwworm detections—cattle in Medina County and sheep in Crockett and Edwards counties—pushing the week’s total to 12 new cases across several counties in Central and West Texas.
Texas remains the only state reporting active cases. By June 24, there were 22 active cases in Texas, out of 24 total cases reported as confirmed through the USDA’s dashboard—plus two cases classified as inactive.
The numbers are especially stark in Edwards County. Edwards rose to six active detections after USDA confirmed one active domestic sheep case on June 24 and added earlier active cases in the same county over the previous weeks. That made Edwards County the most affected county in Texas or the U.S. as of the latest counts.
Medina County’s first case arrived on June 24 as well: one active domestic cattle case. The county sits just west of San Antonio, and its new detection triggered immediate changes in how animals can move.
The USDA’s new detections reshaped the state’s totals and timing. Crockett County added four new active domestic sheep detections over the reporting period, bringing its total to five. Edwards County’s jump was driven by multiple active domestic cattle cases and active domestic sheep cases listed across the most recent confirmations. The week also included three active domestic cattle cases in Terrell County on June 23. and an active domestic goat case in Edwards County on June 21.
As the detections accumulated—six confirmed in a single day—the Texas Animal Health Commission tightened movement restrictions to slow spread. Because of the new detection in Medina County, parts of Medina and two other counties were placed under quarantine effective June 24.
The commission’s quarantine orders cover parts of 18 counties across West, South and Central Texas. They restrict animal movement to reduce the risk that a fly’s eggs end up on a new wound or body opening.
The New World screwworm is a parasitic fly whose larvae feed on living tissue of warm-blooded animals. including livestock. pets. and wildlife. according to the USDA. Infestations begin when a female fly lays eggs on an open wound or body opening. The eggs hatch into larvae that burrow into the wound and feed on living tissue before. after about seven days of feeding. the larvae drop to the ground. burrow into the soil and pupate.
Adult screwworms have orange eyes, a metallic blue or green body, and three dark stripes across the back. USDA says the telltale signs of infection are growing wounds or lesions and the presence of feeding maggots on still-alive animals.
Texas’ quarantine expansion followed a structured timetable, with different zones taking effect on different dates:
Zone 1 (effective June 3): Uvalde and Zavala counties. Zone 2 (effective June 7): La Salle and Webb counties. Zone 3 (effective June 9): Gillespie, Kerr and Kimble counties. Zone 4 (effective June 10): Edwards, Sutton and Val Verde counties. Zone 5 (effective June 12): Tom Green and Coke counties. Zone 6 (effective June 13): Kimble, Schleicher and Sutton counties. Zone 7 (effective June 20): Crockett, Schleicher, Val Verde and Sutton counties. Zone 8 (effective June 22): Terrell and Pecos counties. Zone 9 (effective June 24): Bandera, Medina and Uvalde counties.
The orders say the quarantine will remain in effect until the commission lifts it.
USDA classifies cases as inactive when the animal has fully recovered, or—if treatment was not performed—when appropriate measures were taken to prevent the spread of New World screwworm, including proper disposal of the dead and the infested animal.
Across the confirmation timeline through June 24, Texas has 24 total cases—22 active and two inactive—listed on the USDA’s screwworm dashboard. Those confirmed cases include:
June 24:
– One active domestic cattle case in Medina County.
– One active domestic sheep case in Edwards County.
– Four active domestic sheep cases in Crockett County.
June 23:
– Three active domestic cattle cases in Terrell County.
June 22:
– One active domestic goat case in Terrell County.
June 21:
– Two active domestic cattle cases in Edwards County.
June 20:
– One active domestic sheep case in Crockett County.
June 12:
– One inactive domestic sheep case in Sutton County.
June 11:
– Two active domestic goat and cattle cases in Edwards County.
– One active domestic cattle case in Tom Green County.
– One inactive domestic cattle case in Zavala County.
June 9:
– One active domestic cattle case in Edwards County.
June 8:
– One active domestic goat case in Gillespie County.
– One active domestic cattle case in La Salle County.
June 7:
– One active domestic cattle case in La Salle County.
June 5:
– One active domestic cattle case in Zavala County.
June 3:
– One active domestic cattle case in Zavala County.
The 25th case was confirmed in New Mexico earlier in the month, but it has now been classified as inactive by the USDA.
The pace of detections has sharpened concern among those responsible for livestock health and movement. The week now marks the highest number of reported cases since the first New World screwworm detection on June 3. even as Texas continues to be the only state with active cases while neighboring states had reported a dozen cases in recent detections.
In Texas. the immediate consequence is clear: as case counts rise in counties like Edwards and new detections appear in places like Medina. quarantine boundaries keep expanding. and every additional finding increases pressure on farms. ranches. and pet owners to keep wounds treated and animals protected.
Texas screwworm New World screwworm USDA Texas Animal Health Commission quarantine Edwards County Medina County Crockett County livestock health