On Wednesday, the U.S. Department of Agriculture confirmed the detection of a New World screwworm in a threeweek old bovine in Zavala County in South Texas.
This marks the first case of the parasitic screwworm in Texas in more than half a century. Over 171,700 NWS cases have been reported across Mexico and Central America, according to the U.S. Centers for Disease Control and Prevention.
The NWS is a parasitic fly that lays eggs in the tissue of fresh wounds in warm-blooded animals. Once hatched, larvae feed on the living tissue of the host.
On June 1, State Rep. Don McLaughlin (R-Uvalde) issued an urgent call to action after learning the screwworm was detected one mile away from the U.S. border.
The lawmaker urged Texas leaders to develop an emergency response modeled after Operation Lone Star – the state’s multi-billion-dollar border security initiative launched in 2021.
“For more than a year, I have joined Texas ranchers in sounding the alarm while federal regulators move at a snail’s pace,” McLaughlin said in a news release. “Today, the threat is no longer hundreds of miles away. It is at our doorstep.”
A day after McLaughlin released his statement, U.S. Secretary of Agriculture Brooke Rollins refuted the lawmaker’s claim in an online news conference. Rollins told reporters the closest case was still 25 miles away in Mexico.
The next day, however, the USDA confirmed the case in the young calf in La Pryor, about 50 miles away from the Texas-Mexico border.
FEDERAL RESPONSE
Rollins testified before the House Committee on Agriculture on Thursday where she discussed the arrival of the dreaded parasite. The agriculture secretary emphasized that USDA is using all the tools at its disposal to slow the spread of the screwworm.
“We have now activated our New World Screwworm Response Playbook, which includes detailed protocols and procedures for just this scenario,” Rollins told House committee members. “We have established a 20-kilometer zone around the detection and implementation of quarantines, movement controls and surveillance in the region.
“We have expedited a targeted release of sterile flies in the affected area to prevent the pest from reproducing and are increasing trapping for New World screwworm flies along the border,” she said. “We are wrapping up surveillance and also management in our wildlife.”
In February, the USDA announced the completion of a sterile fly dispersal facility in Edinburg. Additionally, the USDA is developing a sterile fly production facility, also in Edinburg. The South Texas facility will have the capability of producing 100 million flies per week, with an eventual capacity of 300 million. The facility is located at Moore Air Base.
The sterile insect technique combined with surveillance, animal movement restrictions and education -- is a proven method for controlling and eradicating the screwworm. Female NWS flies mate only once. Mating with a sterile male produces unfertilized eggs that fail to hatch.
Releasing sterile males just beyond infested areas creates a buffer zone that prevents migrating flies from reproducing.
MORE ASSISTANCE SOUGHT
State leaders are looking for more assistance. Texas Agriculture Commissioner Sid Miller criticized the USDA’s response so far and has called on President Donald Trump to urge the USDA to deploy the Screwworm Adult Suppression System. SWASS utilizes attractants, bait stations and targeted EPA-approved insecticides to rapidly reduce adult screwworm populations.
“SWASS was developed by USDA, tested by USDA and successfully deployed by USDA to eradicate screwworm in Mexico and Texas when it last appeared,” Miller said in a news statement. “USDA already owns the playbook; the only question is whether USDA will use it before this situation gets worse.”
In January, Gov. Greg Abbott issued a statewide disaster declaration in an effort to prepare Texas for the NWS’ impending arrival. In a Friday press conference, Abbott stressed the need for federal and state partners to work together to combat the spread of the screwworm.
“The scale in which we are operating right now is inadequate,” the governor said. “The speed at which we are operating is inadequate. There is a need by every agency -- whether it state, local or federal -- to understand this can spread like wildfire.”
With the NWS now confirmed within Texas, Abbott opted to expand his statewide disaster declaration to provide all available resources to attack the NWS head-on.
Abbott urged Texas residents to report any unusual wounds found in deer, feral hogs, exotic game animals or other wildlife to the Texas Parks and Wildlife Department.
Potential screwworms found in pets or livestock should be reported to the Texas Animal Health Commission.
