U.S. Faces Return of Flesh-Eating Parasite as New World Screwworm Spreads North
The New World screwworm, a flesh-eating parasite eradicated from the U.S. decades ago, has returned and is spreading northward, threatening livestock, wildlife, pets and potentially people across the country.
What's Happening
The U.S. has eradicated the flesh eating New World screwworm, but now it's back and threatening livestock, wildlife, pets and potentially people as it spreads north. The parasite, which burrows into the flesh of living animals and causes severe tissue damage, represents a significant agricultural and public health threat after being absent from the continental United States for approximately 50 years.
Why It Matters
The screwworm's return is particularly alarming because it feeds on living tissue, creating painful, spreading lesions that can be fatal if untreated. The parasite affects not only livestock farmers' bottom lines but also poses risks to companion animals and, in rare cases, humans. The southward shift of the parasite's range due to climate change and expanded habitat has made eradication efforts more complex than during previous containment campaigns.
Disease Biology and Tracking
A new UC San Diego tracking system aims to monitor the parasite's spread and help authorities coordinate rapid response efforts. The tracking technology is expected to help officials identify new infestations quickly and implement containment measures before the parasite can establish strongholds in new regions.
Response and Next Steps
Agricultural and public health authorities are ramping up surveillance programs, quarantine protocols for affected animals, and public education campaigns. Veterinarians have been alerted to watch for characteristic lesions, and farmers in border regions are being advised to increase monitoring of livestock herds. The CDC and U.S. Department of Agriculture are coordinating with Mexican authorities to slow the northward advance of the parasite population.