has prompted the Colorado state veterinarian’s office to activate plans to protect the state’s cattle industry from the parasite whose larvae feed on animals’ flesh.
The first case reported in the U.S. for several years involves a 3-week-old calf in La Pryor, Texas, about 50 miles from the Mexico border, Agriculture Secretary Brooke Rollins said Wednesday. The Texas state veterinarian established a 12-mile quarantine zone that prohibits the movement of any warm-blooded animal without an inspection.
In Colorado, the state veterinarian’s office is working with the U.S. Department of Agriculture and the livestock industry to prepare for potential impacts, particularly involving trade and interstate movement of livestock, the state agriculture department said in a release.
“Colorado has been diligently preparing for the eventuality of a New World Screwworm detection in the United States and we have a response plan ready,” said Maggie Baldwin, the state veterinarian.
While the case in Texas is concerning, there’s no reason to panic, said Erin Karney Spaur, executive director of the Colorado Cattlemen’s Association.
“Producers should remain vigilant, monitor livestock closely, and contact their veterinarian if they observe unusual wounds or signs of infestation,” she said.
Colorado’s cattle industry has been working with state and federal partners to prepare for the possibility of the New World screwworm fly reaching the U.S., Karney Spaur added.
“I have been briefed and am monitoring the situation very closely and evaluating any next steps needed,” Gov. Jared Polis said.
The Texas case is the first time the New World screwworm fly has been detected in the state since 1966. Recent cases had been confirmed in Mexico as close as 25 miles from the border.
The Associated Press reported that efforts to keep the fly out of the U.S. have included dropping millions of sterile screwworm flies in the area to mate with wild females. The method was used successfully in the past.
The fly is a tropical species that infested cattle during warm weather across the southern U.S. decades ago. The parasite was contained in Panama until late in 2024.
An outbreak occurred in the Florida Keys in September 2016, mostly among wild deer, and was contained early the next year, according to the AP.
The female fly lays its eggs in open wounds or mucous membranes and they hatch into larvae that eat flesh. They can infest livestock, wild mammals, household pets and even humans. Infestations can lead to death if left untreated.
However, officials said the larvae don’t infest food. If properly treated, .
The Associated Press contributed to this report.
