Texas Gov. Greg Abbott has declared a statewide disaster in response to the arrival of the New World screwworm (NWS), a destructive livestock parasite that officials warn could threaten the state’s agriculture industry, wildlife populations, and broader economy.
The declaration follows the discovery of the flesh-eating pest in a three-week-old calf in Zavala County, marking the first known case in Texas after the parasite steadily moved north through Mexico over the past year. The finding has intensified concerns among state and federal officials who have been monitoring the screwworm’s advance toward the U.S. border.
The New World screwworm was eradicated from the United States in 1966 through a large-scale sterile fly release program. Unlike many common parasites, screwworm larvae feed on the living tissue of warm-blooded animals, creating severe wounds that can become fatal if left untreated. The parasite poses a particular threat to livestock producers, whose herds could face significant losses if infestations spread.
Abbott’s latest action expands on a disaster declaration he issued in January after reports of screwworm cases emerged in Tamaulipas, Mexico, just south of the Texas border. State officials have repeatedly warned that the parasite’s movement northward represented a growing risk to Texas ranchers and wildlife managers.
Federal authorities are now working to verify and assess the extent of the Texas case. The U.S. Department of Agriculture announced that it was actively investigating reports of the infestation after local officials raised alarms about the pest’s proximity to the border region.
In his statewide disaster proclamation, Abbott cited the potential for widespread economic damage and emphasized the threat posed to both livestock operations and wildlife populations. The order places all 254 Texas counties under the disaster declaration and enables the state to mobilize resources more rapidly in response to the outbreak.
Several counties had already taken independent action before the governor’s announcement. Kinney County and other border-area jurisdictions issued local disaster declarations as concern mounted over the parasite’s spread. Local officials have also called for a more aggressive response, arguing that every available resource should be deployed to prevent the screwworm from becoming established in Texas.
State leaders fear the pest could expand significantly during the warmer months. While colder winter temperatures may help suppress fly populations, officials have warned that allowing the screwworm to persist through another summer could make eradication efforts much more difficult and costly.
A key component of the state’s response strategy is the use of sterile flies, a proven method that was instrumental in eliminating the screwworm from the United States decades ago. The technique involves releasing millions of sterilized male flies into affected areas. When they mate with wild female screwworm flies, reproduction is halted, causing populations to decline over time.
Texas and federal officials have already invested heavily in this approach. Abbott highlighted a $750 million initiative announced in 2025 alongside Agriculture Secretary Brooke Rollins to construct a sterile fly production facility in Edinburg. The facility, which broke ground last month, is expected to produce up to 300 million sterile flies each week once operational.
Additional efforts have been underway south of the border. The USDA previously opened a sterile fly dispersal facility in Tampico, Mexico, as part of a broader strategy to contain the parasite before it could reach the United States.
Meanwhile, the Texas Animal Health Commission has established a 20-kilometer infested zone in portions of Uvalde and Zavala counties. The order includes quarantine measures and movement restrictions affecting warm-blooded animals and animal carcasses in the designated area.
Abbott has directed state agencies to make personnel and resources available to accelerate sterile fly deployment and speed construction of the Edinburg facility. Officials maintain that the screwworm can be defeated using the same methods that successfully eliminated it decades ago.
The discovery has also prompted concern beyond Texas. Florida agriculture officials announced emergency regulatory changes in response to the parasite’s return to U.S. soil, while members of Congress from Texas continue to press for a coordinated federal response as the state works to contain the threat.
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