New World Screwworm Cases Climb to 12, Including Pet Dog

The latest numbers provided by the USDA show one case in New Mexico and 11 in Texas as of Monday, June 15.

Published: 6/15/2026, 5:47:20 PM EDT

New World Screwworm Cases Climb to 12, Including Pet Dog — A cow reacts, a day after the U.S. Department of Agriculture confirmed that New World screwworm was detected in a Texas calf, near Crystal City, Texas, U.S., June 4, 2026. (Kaylee Greenlee/Reuters)

The U.S. Department of Agriculture (USDA) has confirmed at least 12 cases of the New World screwworm, including one case involving a pet dog.

The latest numbers provided by the USDA show one case in New Mexico and 11 in Texas as of Monday.

NWS is a parasitic fly that causes severe, possibly fatal infestations by feeding on the living tissue of warm-blooded animals.

The first case in the United States was announced on June 3 in a 3-week-old calf in La Pryor, Texas, about 50 miles from the Mexico border. All the cases in the state involved cattle, sheep, and goats.

Meanwhile, the one case in New Mexico involves a pet dog, raising concerns among pet owners. According to federal officials, most dogs and cats in the U.S. are at low risk of NWS. But the risk is considered elevated for pets recently in areas with confirmed cases of NWS.

A quarantine is currently in effect due to the presence of NWS in portions of Coke, Edwards, Gillespie, Kerr, Kimble, La Salle, Schleicher, Sutton, Tom Green, Uvalde, Val Verde, Webb, and Zavala counties in Texas.

Warm-blooded animals located within the quarantined zone may not be moved outside the zone without prior authorization from the Texas Animal Health Commission (TAHC).

According to USDA, quick detection and treatment are vital are essential for protecting livestock and pets.

On June 11, the U.S. Federal Drug Administration (FDA) issued an emergency use authorization for a generic over-the-counter drug to treat NWS in pets, marking the first generic animal drug authorized for use against NWS.

“Generic animal drugs build resilience in our domestic supply chain and play a critical role in expanding the toolkit of U.S. veterinary drugs for New World screwworm,” Timothy Schell, Ph.D., director of the FDA’s Center for Veterinary Medicine, said in a statement “By authorizing this generic treatment, FDA is reinforcing our commitment to providing timely, affordable options to safeguard animal health for American pet owners.”

USDA says the food supply remains safe and that the parasite does not infest meat, fruits, vegetables, or other food products. Animals affected by NWS would be identified during inspection by the USDA Food Safety and Inspection Service, and any impacted animal would be prevented from entering the food supply.

Agriculture Secretary Brooke Rollins outlined actions earlier this month that the federal government has taken to combat NWS, saying that the United States will depend on the same strategy as it did in the late 1950s, which involves releasing sterile insects to suppress the pest’s population.