Screwworm Fly Returns as Key Livestock Threat Near U.S. Border
Pork producers in the United States are being cautioned about the re-emergence of the New World screwworm, a parasitic pest that poses serious risks to livestock health and economic stability.
Although eradicated decades ago, the screwworm has resurfaced in occasional outbreaks, including one in 2016 that affected deer and pets in the Florida Keys.
Experts now warn that the fly may be spreading again, particularly near the Darien Gap, which is no longer a reliable natural barrier.
Kathy Simmons, DVM and Chief Veterinarian for the National Cattlemen’s Beef Association, noted, “From the 1930s to the 1960s, the effort to control and eradicate New World screwworm in the United States costs more than $52 million, adjusted for inflation to today’s value that’s closer to $675 million.”
Today’s landscape makes eradication even more challenging due to the size of livestock populations, animal movement, and the increased wildlife interface.
During a webinar hosted by the Swine Health Information Center and the American Association of Swine Veterinarians, Simmons highlighted the potential economic and logistical impact of a new outbreak. She supported Secretary of Agriculture Brooke Rollins’ decision to suspend imports of cattle, horses, and bison from the southern border to limit the risk.
Outdoor-raised pigs and feral swine are the most susceptible, especially because early detection in wild populations is difficult. Farmers and ranchers are encouraged to reinforce biosecurity measures and report any suspected cases quickly.
Vigilance and preparedness are key as the U.S. pork and livestock sectors confront this rising threat. Immediate action can prevent severe economic losses and health challenges.