The U.S. government has authorized emergency use of animal drugs to fight the reemerging New World Screwworm (NWS), a parasite that poses a serious threat to livestock and the nation’s food supply.
The U.S. Department of Health and Human Services (HHS) issued a declaration enabling the Food and Drug Administration (FDA) to grant Emergency Use Authorizations (EUAs) for animal drugs that could treat or prevent infestations. Currently, no FDA-approved drugs exist for screwworm in the United States, making this the first major regulatory step in decades to prepare against its return.
A Pest Returns After Decades
The New World Screwworm was eradicated from North and Central America decades ago through an intensive eradication program. But since 2022, the pest has been moving northward and is now approaching the U.S.–Mexico border.
The parasite infests warm-blooded animals, including cattle, pets, and wildlife, burrowing into living tissue and causing severe injury or death. While the risk to human health remains low, officials warn the consequences for livestock could be devastating, threatening both agricultural stability and national security.
Emergency Tools for Animal Health
Under the new declaration, the FDA can authorize faster access to drugs already approved for other uses or available abroad. Examples include antiparasitic treatments such as doramectin and ivermectin in cattle, along with several oral medications for dogs and cats.
“These products have not gone through the FDA’s full evaluation for screwworm, but scientific evidence suggests they may help protect animals,” the agency noted. Veterinarians treating food animals are also reminded of restrictions on extra-label drug use, especially with medicated feed.
Coordinated Federal Response
HHS Secretary Robert F. Kennedy, Jr. said the move reflects the need for swift action. “This authorization equips FDA to act quickly, limit the spread of New World Screwworm, and protect America’s livestock.”
Agriculture Secretary Brooke L. Rollins called the parasite a “national security priority,” stressing that cattle ranchers are depending on federal agencies to defend their herds. FDA Commissioner Marty Makary added that the agency will soon issue detailed guidance to veterinarians on how to use any drugs authorized under the emergency order.
Preparing for the Road Ahead
The FDA has launched an online resource page with updates for veterinarians, including information on drugs that may be used under EUA. Officials say continued vigilance and rapid access to treatments will be critical in keeping the parasite from reestablishing itself in the United States.
“With the screwworm advancing north, protecting livestock and food security will require quick action and coordinated defenses,” Makary said.
