New World Screwworm Reappears in the U.S., Prompting Calls for a New Eradication Effort
The New World screwworm (Cochliomyia hominivorax) has been a scourge for livestock and wildlife for decades, but a coordinated effort in the 1950s and 60s successfully eliminated the parasite from the United States. Recent reports, however, have identified the parasite in several animals across the country, indicating that it has returned.
The new findings come from a series of investigations that found flesh‑eating maggots on at least a dozen animals. The presence of the screwworm in the U.S. again signals a potential resurgence of the disease it causes, which can lead to severe tissue damage and even death in infected animals.
Experts warn that re‑eradicating the parasite could take more than a year, a timeline that reflects the complexity of controlling a mobile, highly reproductive insect. The effort would likely involve widespread monitoring, targeted insecticide use, and possibly the release of sterile male flies—techniques that were central to the original eradication program.
The reappearance of the screwworm underscores the importance of ongoing surveillance and rapid response strategies to prevent the spread of invasive species that threaten animal health and agricultural economies.