TWA NWS Best Practices Booklet (downloadable)
Oct. 31, 2026
The Texas Wildlife Association and its partners continue to closely monitor the presence of New World screwworm (NWS) in Texas since the initial detection on June 3. It is essential that Texas hunters, landowners and land managers continue to vigilantly monitor, inspect and report suspected wildlife, livestock and companion animal infestations.
To keep you informed, we are sharing this update as of 12 p.m. on Oct. 30, 2026. Confirmed cases and news since our Oct. 17 update are included below. A list of active and inactive cases is updated daily at 5 p.m. Central at USDA Dashboard.
Rains and cooler temperatures in West Texas, New Mexico and Arizona have contributed to an uptick in detections in the Southwest.
| Confirmed Date | County | Species | Status |
| 29 Oct. 2026 | Dona Ana, NM
Luna, NM |
Cattle
Catlle |
Active
Active |
| 28 Oct. 2026 | Cochise, AZ
Dona Ana, NM Grant, NM Presidio, TX |
Dog
Dog Domestic Cat Cattle |
Active
Active Active Active |
| 27 Oct. 2026 | Dona Ana, NM
El Paso, TX |
Dog
Dog |
Active
Active |
| 26 Oct. 2026 | Luna, NM | Cattle | Active |
| 24 Oct. 2026 | Dona Ana, NM | Cattle
Sheep |
Active
Active |
| 23 Oct. 2026 | Hudspeth, TX | Cattle
Cattle |
Active
Active |
| 22 Oct. 2026 | Hidalgo, NM | Cattle | Active |
| 21 Oct. 2026 | Otero, NM
Pecos, TX Val Verde, TX |
Cattle
Elk Cattle |
Active
Inactive Active |
| 20 Oct. 2026 | Jeff Davis, TX | Cattle | Active |
| 18 Oct. 2026 | Brewster, TX | Horse | Active |
Active cases are those that involve ongoing disease mitigation efforts, including treatment and wound management of the infested animal until all wounds have healed.
Inactive animal cases refer to situations where mitigation activities are no longer required. Either the animal has fully recovered—with wounds healed and treatment completed—or, in cases where treatment was not performed, appropriate measures have been taken to prevent the spread of NWS, such as appropriate carcass management of a deceased infested animal.
News and updates
October 21: First wildlife case documented in Texas
USDA, Texas Animal Health Commission (TAHC) and Texas Parks and Wildlife Department (TPWD) received confirmation of NWS in an elk on a large game ranch in Pecos County. The hunter-harvested elk was observed with an infested wound by a hunter and reported for collection and submission.
October 23: Infested Zone modified
The USDA/APHIS released movement and quarantine restrictions from a portion of Infested Zone 12.A which includes areas of Crockett and Pecos counties and renamed a larger area as Infested Zone 12.B, which includes portions of Crockett, Pecos and Terrell counties.
Check the Texas Animal Health Commission NWS interactive zone map to verify infested zone locations.
October 26: USDA continues to reopen border to livestock imports
The USDA resumed livestock imports at its Columbus, NM port of entry. This is the third livestock port of entry reopened under enhanced inspection and quarantine protocols since late August, following ports in Douglas, AZ and Santa Teresa, NM. The USDA also began processing equine imports at the Santa Teresa facility this week.
October 28: First case confirmed in Arizona
The USDA/APHIS confirmed a case of NWS in a dog in Cochise County, AZ. Federal and state officals are implementing response activities outlined in the APHIS NWS Response Playbook.
TWA Best Practice document now available
As you head outdoors this fall, take along the TWA Best Practices for Screwworm Detection & Reporting in Wildlife. This 12-page booklet is designed to serve as an NWS resource for TWA members, hunters, ranchers, landowners and managers, and anyone who enjoys time outdoors. We now have printed copies that will be made available at future TWA events across the state.
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What to look for
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Open sores or wounds with live maggots
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Animals shaking heads or acting irritated
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Foul, rotted flesh odor
Identification
NWS are parasitic flies that lay eggs in open wounds, genitalia or mucous membranes such as the umbilical cords of newborns, the nostrils, eyes or mouths of live warm-blooded animals. These eggs hatch into parasitic larvae (maggots) that only feed on living tissue, unlike other fly larvae that prefer dead or necrotic tissue. NWS larvae only burrow or “screw” into living tissue with sharp mouth hooks, giving them a screw-like appearance. Infested wounds quickly become infected and, if left untreated, will kill infested animals.
What you can do
Regularly reviewing game cameras, observations of wildlife while hunting or viewing animals, and inspection of hunter-harvested wildlife are important tools that can be used for NWS surveillance. While all warm-blooded mammals can be infested with NWS, white-tailed deer, jackrabbits, cottontails, small mammals and turkeys are more commonly affected. Instances of live or just-harvested animals with live maggots should be reported immediately.
Texas Parks and Wildlife Department (TPWD) has established procedures for the take of certain wildlife suspected to be infested with NWS.
Inspect all harvested wild game. If a harvested animal has a suspected infection, utilize a tarp or other barrier to keep larvae from coming into contact with the soil. Report the animal to your TPWD biologist, and follow guidelines for carcass treatment and disposal. Carcasses with no sign of infestation can be disposed of through normal processes.
How to report and who to report to
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Report native wildlife sightings to a local TPWD biologist or call (512) 389-4505.
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Livestock and exotic wildlife: 1-800-550-8242
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Pets: contact your local veterinarian
Pesticides for NWS
For a list of currently registered products that meet the U.S. Environmental Protection Agency’s (EPA) efficacy data, please visit Pesticides for Control of New World Screwworm.
The EPA has approved Fyfanon® ULV AG (Malathion) for treating the ground around dead wildlife when NWS larvae have already exited the carcass to pupate in the soil.
What is being done
Sterile flies are a proven technique to eliminate this pest. It is estimated that to push the screwworms back out of the United States, 500 million flies per week will need to be produced and dispersed. The following actions are in place, or under development, to expand our sterile fly resources:
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COPEG production facility (Pacora, Panama) – 100 million sterile flies produced per week. This is a USDA facility.
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Metapa production facility (Metapa, MX) – The facility opened June 27 with current production of 30 million flies per week, with estimated production of 60-100 million flies per week by the end of 2026. This is a USDA Facility.
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Moore Air Base dispersal facility (Edinburg, TX) – Completed in February 2026, this facility allows USDA to receive flies from other locations but base their distribution operations from Texas. Capable of dispersing 100 million flies per week.
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Moore Air Base production facility (Edinburg, TX) – Groundbreaking was held in April 2026. Phase 1 is estimated to be complete by spring 2027 and produce 100 million flies per week by the end of the year. Phase 2 is estimated to be complete in 2028 and produce an additional 200 million flies per week for a total of 300 million flies per week once full capacity is reached.
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NovoFly – new genetic technology that will allow for the production of male only sterile flies. This technology, which is nearing full approval, will effectively double current production capabilities. TWA provided comments to the EPA in favor of this technology in April of 2026.
TWA statement on potential feed-through treatment for wildlife
The Texas Wildlife Association continues to work with our state and federal partners to identify and share tools that Texas landowners can use in the prevention and treatment of NWS.
We are encouraged by the recent announcement of collaborative field trials involving the United States Department of Agriculture, the Food and Drug Administration, and the Texas Parks and Wildlife Department to evaluate the use of a feed-through treatment for wildlife applications. This research represents an important step toward developing science-based management options to protect Texas wildlife resources as the construction of vital sterile insect infrastructure moves forward.
We look forward to the results of these trials and are hopeful they will determine whether this treatment can be demonstrated to be both safe and effective in preventing NWS infestation in wildlife.
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