The invading parasitic New World screwworm ( Cochliomyia hominivorax ) is digging its sharp mouth hooks deeper into the United States.

This week, federal and local officials in Texas confirmed the first known infestation of screwworm in wildlife since the parasite reemerged in the country this year—a female elk killed by hunters. Though total cases of screwworm are still low, this month has seen an increase.

“We encourage all hunters and landowners to be vigilant for signs of New World screwworm while they are out in the field this season,” said Alan Cain, Wildlife Division Director in the Texas Parks and Wildlife Department, in a statement released Wednesday.

The screwworm’s return

The screwworm is actually a species of fly, though its larval form is the real cause of concern. Unlike many species, screwworm maggots love feeding on the living flesh of warm-blooded animals.…