Flesh-eating screwworm has reached the US — a comeback driven by organized crime

 When the US Department of Agriculture reported last week that it detected a case of New World screwworm in a Texas calf, ecologist Jeremy Radachowsky was not surprised.

Radachowsky, the Mesoamerica and Western Caribbean director for the Wildlife Conservation Society, had long warned of the resurgence of the screwworm fly: a species with a life cycle that sounds like the plot of “Alien.”

Screwworms incubate exclusively in the wounds or orifices of warm-blooded animals such as cows, dogs, horses and human beings. The parasite had previously been eradicated in North and Central America through a multimillion-dollar, decades-long program of fly sterilization led by the United States.

But Radachowsky and other researchers have warned for years that illegal cattle smuggling has quickened the return of screwworm to its ceded territory in Central America. It has since spread northward to Mexico, Texas and, as of this week, New Mexico.

Cattle trafficking is a long-standing issue in Central America, where organized crime groups smuggle livestock, some of which carry screwworm, across borders without legitimate health screenings, according to a 2022 report from the think tank InSight Crime.

The report notes that cattle trafficking is lucrative on its own, but the phenomenon also allows criminal groups to launder money through smuggled cattle and control territory via jungle deforestation to make room for massive cattle ranches.

The influx of cattle and their traffickers into the forests of Central America has had serious consequences, Radachowsky said, including receding tree cover, growing violence and the spread of new diseases.“Every cow that is being moved illegally has the potential to carry a screwworm and other diseases,” Radachowsky said. “Something that’s really frightening as well is that you have avian flu transmitted by cattle and tuberculosis.”

The USDA and the Mexican Agriculture Department have announced new efforts in breeding and releasing sterilized flies to hamper the spread of screwworm. The last time the screwworm wriggled its way into Texas, in the 1970s, the outbreak caused hundreds of millions of dollars in cattle losses.