The U.S. Department of Agriculture (USDA) confirmed a second New World screwworm (NWS) case in South Texas on June 5, finding the flesh-eating parasite in a one-month-old calf in Zavala County, 5.6 miles from the first U.S. detection since 1966, confirmed two days earlier in La Pryor.
USDA Under Secretary Dudley Hoskins said both detections fall within an established movement control zone where sterile fly dispersal is already underway. “USDA has not wasted any time in this fight, we have defeated New World screwworm before, and we will do it again,” Hoskins said. USDA stated the food supply is not at risk, as NWS larvae do not infest meat or food products.
As part of USDA’s efforts to keep New World screwworm (NWS) out of the United States, @USDA_APHIS Wildlife Services is leading a coordinated effort to inspect wildlife for signs of NWS infestation.
To date, they’ve inspected more than 18,000 wild animals (102 different species)… pic.twitter.com/MTgoXhHxHV
— Dept. of Agriculture (@USDA) May 18, 2026
Canada’s Food Inspection Agency (CFIA) announced Friday it will temporarily bar livestock, including horses, that were present in Texas within the prior 21 days from entering Canada.
Texas Gov. Greg Abbott issued a statewide disaster declaration and warned that without greater sterile fly output, “we cannot make it through a second summer.” USDA is dispersing roughly 8 million sterile flies per week in Texas, against a threshold of 500 to 600 million per week that past eradication campaigns required.
🚨 With the recent detection of New World screwworm in a 3-week-old bovine in Zavala County, TX, USDA urges residents to contact your veterinarian right away if you see any suspicious wounds, maggots, or infestations in your animals or herd.
If you see signs of maggot… pic.twitter.com/lxxsjIgDcb
— Dept. of Agriculture (@USDA) June 4, 2026
The sole operational sterile fly facility in the Western Hemisphere is in Pacora, Panama, producing roughly 100 million flies per week. A USDA-funded conversion site in Metapa, Mexico, is expected to begin producing 100 million flies per week next month.
Abbott pledged Texas funds for round-the-clock construction of a $750 million facility at Moore Air Base in Edinburg, where the U.S. Army Corps of Engineers broke ground in April 2026, targeting 300 million flies per week at a planned November 2027 opening.
“Surveillance and reporting are a priority,” Texas Farm Bureau President Russell Boening said. “The quicker an infestation is found, the quicker the New World screwworm can be eradicated.”
