The USDA is leading a coordinated emergency response to contain the outbreak.
What Is Screwworm Infection?
Unlike other maggots that eat dead flesh, screwworms can cause severe damage to living tissue as they tear in with sharp mouth hooks.
“The infections can be horrific and they can absolutely kill the host animal, particularly if they’re very young, or very old,” says Sally Anne DeNotta, DVM, PhD, an associate professor in the department of large animal clinical sciences at the University of Florida’s College of Veterinary Medicine in Gainesville.
Screwworms Primarily Affect Livestock
Can Screwworms Infect Humans Humans?
Humans most at risk of New World screwworm infection include those who:
- Work closely with livestock or wildlife animals in an area with screwworm activity
- Travel to regions and countries where screwworm is consistently present, such as South America, Cuba, Haiti, and the Dominican Republic, or to areas currently experiencing an outbreak
- Have open sores or wounds that may attract screwworm flies
- Are unhoused or sleeping outdoors in areas experiencing screwworm activity
Unlike many infectious diseases, screwworm doesn’t spread from animal to animal or from animals to humans, says Catherine Troisi, PhD, a professor of management policy and community health at the UTHealth Houston School of Public Health.
“Infected animals aren’t contagious,” says Dr. Troisi.
Beef Remains Safe to Eat Food and an Emergency Response Is Underway
Beef hamburgers, steaks, and other beef products remain safe to eat, according to Dr. DeNotta.
“The public should know that this is not a risk to the U.S. food supply and federal authorities are responding aggressively to eradicate the problem,” she says.
“Releasing sterile male flies will prevent the female from laying eggs, ending the cycle,” says Sharon Nachman, MD, the chief of pediatric infectious diseases at Stony Brook Children’s Hospital in New York. “Enough sterile male flies have to be released at the correct time and place to help stop this parasite from moving further into U.S. farmland.”
Such sterile flies, though, are in short supply at the moment.
“The only manufacturing of these sterile flies is in Panama, but they have limited capacity to produce them. We will need many millions more to stop this infestation,” says Troisi.
