The U.S Department of Health and Human Services confirmed to Scripps News that it is responding to the New World Screwworm outbreak by activating the Centers for Disease Control and Prevention emergency response at “level 3,” which is the agency’s “lowest” level.
Although the risk for human infections is rare, the CDC documented a human case in 2025 when a traveler returned from a trip to Central America, where the pest is prevalent.
New World Screwworm is a devastating parasite that feeds on the live flesh of warm-blooded animals. It spreads when female screwworm flies lay eggs in open wounds. However, infected animals can be treated and recover.
According to a USDA tracking system, there are at least nine cases in Texas and New Mexico affecting cattle, goats, and a dog.
Nearby states, like Colorado, are taking precautions by setting up restrictions on how animals can be transported in and out of the region. The state also set up a new rule affecting how cats and dogs are inspected prior to entering the state.
“New World Screwworm is a challenging pest,” said Maggie Baldwin, Colorado’s state veterinarian. “Not only does one case obviously harm the animal that has been affected, but the response to one single case can be very robust, it can be very intensive…it is costly not only to the animal owners but it’s costly to the state and the federal government, and we don’t want to let that fly set up a population here in Colorado.”
This week, the FDA approved an emergency medication for cats and dogs if infestations reach domestic animals in the coming days. Generic Nitenpyram tablets can be used to treat dogs and cats that weigh at least two pounds and are at least four weeks old.
“The U.S. government is maintaining an aggressive approach to stop the spread and eradicate this pest,” said U.S. Health and Human Services Secretary Robert F. Kennedy Jr.
U.S. Secretary of Agriculture Brooke Rollins said this week the USDA has 110 full-time staffers working on this problem. The agency has deployed millions of sterile flies in Texas in an effort to stop the pest’s spread.
“This technology works and it works well, and it is proven over and over again,” Rollins said Thursday.
