Key facts
- The CDC has activated a formal emergency response to the New World screwworm.
- The declaration signifies increased federal resources and investigation into the outbreak.
- At least seven cases of screwworm have been confirmed in Texas and New Mexico in livestock and one dog.
- The USDA is dispersing sterile flies to control the spread of the screwworm.
- The FDA previously authorized emergency use of an over-the-counter tablet for pets to treat screwworm.
The Centers for Disease Control and Prevention (CDC) has activated a formal emergency response to the New World screwworm, a parasitic fly that has reappeared in U.S. livestock for the first time in decades. The declaration indicates an escalation of federal efforts, including increased resources and investigation into the outbreak, which has been confirmed in at least seven animals across Texas and New Mexico, including cattle, a goat, and a dog.
The Department of Agriculture is leading the animal-side response, monitoring livestock and deploying sterile flies to control the parasite's spread. The CDC's involvement signals a proactive approach to potential human exposure, though human infestations are rare and currently have no reports. The risk is concentrated in areas where the flies are circulating, particularly for individuals with open wounds or those who work closely with livestock.
This heightened response is described by Agriculture Secretary Brooke Rollins as part of the Trump administration’s "whole of government approach." The FDA has also authorized emergency use of an over-the-counter tablet for pets to treat screwworm, with nitenpyram tablets designed to kill most larvae within hours. While treatable, screwworm infestations can cause serious wounds. The parasite was eradicated in the U.S. in the 1960s, with a previous outbreak occurring in Florida between 2016 and 2017.