A flesh-eating parasite is at our borders. What happens if it spreads? 

A worker walks through empty corrals at the Union Ganadera Chihuahua cattle import facility in Santa Teresa, New Mexico, on June 20, 2025. | Paul Ratje/Bloomberg via Getty Images A Maryland resident who traveled to El Salvador came home last month with an unwelcome souvenir: larvae of the New World screwworm burrowing in their flesh.  The patient has since recovered from the painful parasite, and Maryland health officials confirmed that there’s no sign of transmission to anyone else. But the case is historic: It’s the first time in more than half a century that a human in the US has b