06/08/2026
SDA Confirms Two Additional Cases of New World Screwworm in the United States
The State of Texas continues to lead response with USDA support.
WASHINGTON, D.C., June 8, 2026 – Today, the U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed two additional cases of New World screwworm (NWS) in the United States – a calf in La Salle County, Texas, and a dog in Andrews County, Texas.
Epidemiological investigations are ongoing for both cases. A veterinarian in Andrews County submitted the samples from the infested dog. Details on this case will be shared as they are available, but early reports indicate the dog was recently in Mexico.
NWS is a serious pest that threatens livestock, pets, wildlife, and, in rare cases, people. The larvae burrow into the living tissue of animals, causing severe wounds, animal suffering, and significant economic losses.
“Over the past week, USDA has identified and expeditiously confronted four confirmed detections of New World screwworm. While we address these instances that require immediate attention, and continue to sample suspected cases, we are simultaneously working to eradicate the pest entirely,” said Dudley Hoskins, Under Secretary for Marketing and Regulatory Programs. “We need the partnership of animal owners across the region – please stay vigilant, check your animals closely, and report anything that looks suspicious. Together, we can protect our livestock, our communities, and the health of animals nationwide.”
USDA and TAHC Response
USDA and the Texas Animal Health Commission (TAHC) continue to lead an aggressive unified response, with a total of 75 people actively responding on the ground and hundreds of additional people around the country providing laboratory diagnostics, logistics, treatment distribution, air operations, outreach, operational planning, and resource support for the response. APHIS and TAHC will continue to surge additional trained personnel as needed to ensure an effective response.
For each new case, USDA and TAHC implement actions outlined in the NWS Response Playbook, including:
Establishing and maintaining a 20km infested zone with quarantines, movement controls, and heightened surveillance around confirmed detections
Increasing trapping along the border and outside the dispersal zone
Conducting surveillance and management strategies in wildlife
Implementing targeted outreach to local producers, veterinarians, and communities
Intensified Sterile Fly Releases
USDA continues to release sterile flies over and just outside of the infested areas. To ensure sterile fly release operations can be deployed to affected areas in Texas and in northern Mexico near the border as quickly and efficiently as possible, USDA has activated the sterile fly dispersal facility at Moore Air Base in Edinburg, Texas. Sterile pupae arrived at the facility on Friday, and aerial dispersal flights originating from the base will begin tomorrow.
Because it is important to continue ongoing surveillance efforts while releasing sterile insects, it is possible that sterile NWS flies could be caught and/or reported. To ensure officials can tell the difference between sterile and wild NWS flies, USDA dyes the sterile pupae, and the dye transfers to the sterile flies when they hatch. The fluorescent green or orange dye glows under UV light and may also be visible to the naked eye. If a sterile fly is captured in a trap, this dye allows animal health officials to quickly rule the fly out as a threat.
Guidance for Pet and Livestock Owners
USDA urges everyone in the area to check animals for:
Draining or enlarging wounds
Maggots or egg masses
Signs of discomfort
Lesions in body openings (nose, ears, genitalia, umbilical area)
