Animal Health Officials Respond to Second Detection of New World Screwworm in the United States

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Animal Health Officials Respond to Second Detection of New World Screwworm in the United States

FOR IMMEDIATE RELEASE
Contact: [email protected]

WASHINGTON, D.C., June 5, 2026 - The U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed a second detection of New World screwworm (NWS) after testing a number of suspect cases. The confirmed case was found in a one-month-old calf in Zavala County, Texas, approximately 5.6 miles away from the first confirmed detection. APHIS and our Texas partners continue to collect and test other samples from the surrounding area which have come back negative.

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.

"USDA has responded expediently with respect to this second detection, demonstrating our utmost preparedness. This second detection is within the established movement control zone and enhanced sterile insect dispersal area." said Dudley Hoskins, Under Secretary for Marketing and Regulatory Programs. "Many models projected this pest would reach the United States last year, but thanks to USDA's phenomenal work and our cooperation with state, federal, and industry partners, we've held it off until now-when we are far more prepared to respond. USDA has not wasted any time in this fight, we have defeated New World screwworm before, and we will do it again."

USDA Strike Team and Rapid Deployment Capacity

An APHIS strike team is already on-site in Texas. This team includes veterinary medical officers and animal health technicians - experienced experts who serve as USDA's boots on the ground response force. APHIS is fully positioned to surge additional trained personnel as needed.

The National Veterinary Services Laboratories (NVSL) has deployed an entomologist to the USDA Agricultural Research Service laboratory in Kerrville, Texas, to expedite confirmation processes by positioning NVSL diagnostic assets in the area.

APHIS has also deployed two dedicated NWS response cargo trailers. Each 24-foot trailer serves as a mobile preparedness and field operations center. Once unloaded, the trailers convert into operational and laboratory space, providing USDA personnel with the equipment and environment necessary to mount a rapid, efficient response.

Treatment Resources and Supplies

The U.S. Food and Drug Administration has issued emergency use authorizations for several NWS treatments for different species. Currently, there are treatments available to support cattle, horses, swine, goats, captive exotic animals, and wildlife.

The National Veterinary Stockpile is actively procuring additional tools to treat and prevent NWS. USDA is working with federal and regulatory partners, and within federal purchasing processes, to secure more treatment options that are flexible, safe, and effective.

The National Veterinary Stockpile has relocated NWS treatment supplies to Texas to better support affected producers in the infested zone. If you or anyone you know needs access to these treatment supplies, they are now available and can be obtained by reaching out directly to the Texas Animal Health Commission (TAHC).

Intensified Sterile Fly Operations

As part of the established NWS eradication strategy, USDA began releasing sterile flies over the area on June 4. These missions will disperse 2 million sterile screwworms twice a week to disrupt the pest's lifecycle.

In addition to aerial releases, USDA is shipping another 4 million sterile flies per week to Texas. These will be deployed using 24 ground release chambers, strategically placed in and around the detection zone to maximize impact.

Unified Response Actions in Texas

USDA and TAHC remain in unified incident command and are implementing actions outlined in the NWS Response Playbook, including:

• Maintaining a 20-km infested zone with quarantines, movement controls, and heightened surveillance around the initial detection and establishing a new 20-km infested zone around the latest detection
• 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

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)

Anyone who suspects a screwworm infestation should immediately contact their veterinarian, state animal health official, or USDA.

Though rare in people, anyone who notices a suspicious lesion should seek immediate medical care.

Food Safety

The U.S. food supply remains safe. Screwworms do not infest meat, fruits, vegetables, or other food products. Any affected animal would be identified during USDA Food Safety and Inspection Service inspection, and no contaminated product would enter commerce.

Continued Federal Leadership

For more than a year, USDA has led a unified national response effort, deployed enhanced surveillance, strengthened its border defense strategy, and supported cross-border operations in Mexico and Central America. These efforts have bought critical time and ensured the United States is better prepared to respond to these detections.

More information about New World screwworm is available at Screwworm.gov.