New Mexico, federal officials preparing for flesh-eating flies that prey on livestock

To borrow a phrase from Tom Paterson, president-elect of the New Mexico Cattle Growers' Association, infestations of the New World screwworm fly are "pretty gross."

Common in the Caribbean and Central America, the flies' larvae burrow into the flesh of warm-blooded creatures — including livestock, pets, wildlife and, in some rare cases, people — and feast upon healthy tissue, causing severe and sometimes deadly damage.

"They will start eating on the animal, on it's flesh," said Paterson, a Catron County rancher. "They'll literally eat it."

Once a major threat to American agriculture, New World screwworm flies were eradicated from the U.S. in the 1960s and largely haven't returned.

However, the flies have been getting uncomfortably close in recent months. The U.S. Department of Agricult