The USDA’s Animal and Plant Health Inspection Service approved the release of previously designated New World Screwworm-infested zones in Texas on Aug. 31, marking the first significant containment milestone in an outbreak that has threatened livestock and wildlife across multiple states.
The zone release indicates that screwworm populations in the affected Texas areas have been suppressed to levels that allow the lifting of livestock movement restrictions — welcome news for ranchers whose operations were curtailed by quarantine measures.
New World Screwworm is a parasitic fly whose larvae feed on the living flesh of warm-blooded animals, including cattle, deer and, in rare cases, humans. The pest was eradicated from the United States decades ago through a massive federal sterile-insect release program, making its reappearance a serious biosecurity concern.
APHIS had established infested zones in Texas that restricted the movement of livestock, imposed inspection requirements and triggered a multi-agency response involving the sterile insect technique — the release of sterilized male flies that mate with wild females and produce no viable offspring, according to the agency.
For Texas ranchers, the zone release means reduced regulatory burden and the ability to resume normal cattle marketing and transportation. For the broader cattle industry, it signals that federal containment efforts are working.
The outbreak has drawn an unusually broad government response, including involvement by the Defense Advanced Research Projects Agency and U.S. Southern Command, which airlifted a sterile insect irradiator to Panama to suppress the pest before it could spread further northward.
APHIS continues to monitor for screwworm activity and maintains its sterile fly release operations in the region.