US Department of Health and Human Services authorizes emergency use of animal drugs for New World screwworm

The US Department of Health and Human Services (HHS) has declared that the FDA can now issue emergency use authorizations for animal drugs to treat or prevent infestations caused by New World screwworm (NWS). According to the announcement, the declaration applies only to animal drugs.

“Today we are taking decisive action to safeguard the nation’s food supply from this emerging threat,” HHS Secretary Robert F. Kennedy, Jr, said in the announcement.1 “This authorization equips FDA to act quickly, limit the spread of [NWS], and protect America’s livestock.”

NWS targets warm-blooded animals, including cattle, pets, wildlife, and, less commonly, humans. An NWS infestation may cause severe tissue damage and, in some cases, death.1

Although the public health risk to humans remains low, its reemergence poses a potential threat to animal health and livestock production. “This parasite poses an emerging threat to livestock and food security, with potential impacts on both national security and animal health,” the HHS wrote in its announcement.1

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NWS was eradicated from North America and Central America decades ago but has been advancing north since 2022 and is now close to the US border with Mexico.1 According to Christopher Lee, DVM, MPH, DACVPM, a preventive medicine specialist focusing on parasitology, immunology, and infectious disease, an NWS invasion is likely, with predictions that the parasite will make its way into the US by this year or next year.2

“We have been seeing [NWS] moving up from South America, through every single country in Central America, and has touched down into Mexico,” Lee said in a dvm360 Vet Watch video.2 “Currently, we are looking at the numbers nearly doubling every couple of weeks.”

There are currently no FDA-approved treatments for NWS in the US.1 Under the new emergency authorization, however, the FDA can temporarily authorize the use of certain animal drugs that are approved for other conditions or in other countries but not formally approved for NWS in the US, giving veterinarians and producers quicker access to options for protecting animals and the food supply. The emergency use authorization allows veterinarians, farmers, and animal health officials to have timely access to options for protecting pets, livestock, and the US food supply, the HHS said.1

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“FDA is acting swiftly and responsibly to help ensure we have the necessary tools to prevent and control [NWS], minimizing risks to agriculture and public health,” said Marty Makary, MD, MPH, FDA commissioner.1

References

1. HHS allows FDA emergency use of animal drugs to combat New World screwworm, protect US food supply. News release. US Department of Health and Human Services. August 19, 2025. https://www.fda.gov/news-events/press-announcements/hhs-allows-fda-emergency-use-animal-drugs-combat-new-world-screwworm-protect-us-food-supply
2. Lee C, Alaburda R. Vet Watch update: New World screwworm. dvm360. May 16, 2025. Accessed August 19, 2025. https://www.dvm360.com/view/vet-watch-update-new-world-screwworm