- USDA confirmed new NWS cases in a calf in La Salle County and a dog in Andrews County, Texas.
- Investigations are ongoing, with preliminary reports indicating the infected dog had recently been in Mexico.
- USDA and the Texas Animal Health Commission have 75 personnel actively responding on the ground, supported by hundreds more nationwide.
- Aerial sterile fly dispersal operations from Moore Air Base in Edinburg, Texas, are set to begin following the arrival of sterile pupae.
- Animal owners are urged to inspect livestock and pets for suspicious wounds, maggots, or signs of infestation and report concerns immediately.
- USDA emphasized that the U.S. food supply remains safe and unaffected by New World screwworm.
USDA’s Animal and Plant Health Inspection Service (APHIS) has confirmed two additional cases of New World screwworm (NWS) in the United States, identifying infestations in a calf from La Salle County, Texas, and a dog from Andrews County, Texas.
The detections represent the latest developments in an ongoing response effort aimed at containing and eradicating the parasitic pest before it can become established within U.S. livestock and wildlife populations.
Investigations Underway
Federal officials said epidemiological investigations remain active for both cases. Samples from the infected dog were submitted by a veterinarian in Andrews County. Early reports indicate the animal had recently traveled in Mexico, although additional details have not yet been released.
New World screwworm is considered a significant animal health threat because its larvae invade living tissue, creating severe wounds that can lead to animal suffering, secondary infections, and substantial economic losses. The parasite can affect livestock, companion animals, wildlife, and, in rare instances, humans.
“Over the past week, USDA has identified and expeditiously confronted four confirmed detections of New World screwworm,” said Dudley Hoskins, Under Secretary for Marketing and Regulatory Programs. “While we address these instances that require immediate attention, and continue to sample suspected cases, we are simultaneously working to eradicate the pest entirely.”
Coordinated Federal and State Response
USDA and the Texas Animal Health Commission (TAHC) continue to coordinate response activities across affected regions. Officials reported that 75 personnel are currently deployed in field operations, while hundreds of additional staff members nationwide are supporting laboratory diagnostics, logistics, treatment distribution, air operations, outreach, planning, and resource management.
For each confirmed detection, response teams are implementing measures outlined in the New World Screwworm Response Playbook, including:
- Establishing and maintaining 20-kilometer infested zones with quarantines, movement controls, and enhanced surveillance.
- Expanding trapping activities along the U.S.-Mexico border and beyond known dispersal zones.
- Conducting surveillance and management efforts in wildlife populations.
- Providing targeted outreach to producers, veterinarians, and local communities.
Sterile Fly Program Expands
A key component of the eradication strategy remains the release of sterile screwworm flies to suppress wild populations.
USDA announced that sterile pupae recently arrived at the Moore Air Base dispersal facility in Edinburg, Texas. Aerial release operations from the facility are scheduled to begin immediately, allowing sterile flies to be distributed rapidly across affected areas in South Texas and northern Mexico.
Officials noted that surveillance efforts will continue during release operations. To distinguish released sterile flies from wild populations, USDA marks sterile pupae with fluorescent green or orange dyes that remain visible after emergence and can be detected under ultraviolet light.
Guidance for Animal Owners
USDA is encouraging livestock producers, pet owners, and veterinarians to remain vigilant and monitor animals for signs of infestation, including:
- Draining or enlarging wounds.
- Maggots or egg masses.
- Signs of discomfort or irritation.
- Lesions in body openings such as the nose, ears, genitalia, or umbilical region.
Anyone suspecting a screwworm infestation should contact a veterinarian, state animal health officials, or USDA immediately. In Texas, suspected livestock cases should be reported directly to TAHC.
Although human cases are uncommon, individuals who notice suspicious lesions are advised to seek prompt medical attention.
Food Supply Remains Safe
USDA emphasized that New World screwworm does not pose a food safety threat. The parasite does not infest meat, fruits, vegetables, or other food products. Officials stated that affected animals would be identified through existing inspection systems, preventing contaminated products from entering commerce.
Ongoing Transparency Efforts
Federal and state officials said they remain committed to providing timely updates as investigations continue. USDA and its Texas partners plan to maintain a sustained operational presence in affected areas while working toward complete eradication of the pest.
Information sourced from the U.S. Department of Agriculture press release.
