Policy

New World Screwworm found in Texas

The Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the detection of a New World screwworm (NWS) in a calf in Zavala County, Texas.

The affected animal is a 3-week-old calf and larvae were identified in its umbilical area. To date, there have been no further detections, according to the USDA.

Dudley Hoslins, the undersecretary for Marketing and Regulatory Programs at USDA said the modeling had predicted NWS entering the country in 2025, but industry and government partners have been able to “buy time for this moment.”

NWS is a serious pest that affects livestock, pets, wildlife and less commonly, people and birds. NWS larvae (maggots) burrow into the flesh of living animals, causing serious damage to livestock and economic losses.

USDA and Texas officials are taking immediate action to contain the parasite, following the strategies and actions outlined in the NWS Response Playbook (884.59 KB). This includes:

• Forming a unified Incident Command Team with the Texas Animal Health Commission and deploying response personnel to the area;
• Establishing a 20 km infested zone around the detection and implementing quarantines, movement controls and surveillance in this area;
• Expediting targeted release of sterile NWS flies (423.58 KB) by immediately deploying ground release chambers in the area, in addition to the 4 million sterile flies per week already being released aerially in the area;
• Increasing trapping for NWS flies along the border and just outside of the dispersal area;
• Implementing NWS surveillance and management strategies in wildlife; and
• Conducting targeted outreach in the local area.

Additionally, USDA’s National Veterinary Stockpile stands ready to assist and will provide resources including treatments, equipment and logistics as needed to help the response.

USDA will continue to work with state departments of agriculture, animal health officials, industry and producers to mitigate economic impacts of restrictions as much as possible, including negotiating with trading partners to regionalize any trade restrictions on live animals, limiting them to defined geographic areas.

NWS maggots can infest livestock and other warm-blooded animals, including in rare cases people. They most often enter an animal through an open wound and feed on the animal’s living flesh.

USDA urges residents in the area to check their pets and livestock for signs of NWS. Look for draining or enlarging wounds and signs of discomfort. Also look for screwworm larvae (maggots) and eggs in or around body openings, such as the nose, ears and genitalia or the navel of newborn animals. Any suspected cases should be reported to the USDA area veterinarian in charge immediately.

People who notice a suspicious lesion on their body or suspect they contracted screwworm, they should seek immediate medical attention.

The USDA emphasized that screwworms do not infest meat, fruits, vegetables or other food sources. USDA’s Food Safety and Inspection Service (FSIS) ensures that the nation’s commercial supply of meat, poultry, and egg products is safe and properly labeled. Under the Federal Meat Inspection Act USDA’s Food Safety and Inspection Service inspection personnel must inspect all eligible animal species unless they are exempt or covered by a state inspection program.

Any evidence of screwworm infestation in an animal would be identified during these inspections, and any contaminated product from an affected animal would not be allowed to enter the food supply, according to the USDA.

For more than a year, USDA has led a unified response to NWS with Mexico and Central America to combat the pest and push NWS away from the United States. These efforts have bought time for USDA to increase domestic preparedness efforts, the agency said in a release.

Learn more about New World screwworm at Screwworm.gov.