The New World screwworm, a flesh-burrowing parasite that can chew through livestock, pets, and humans, is encroaching further into the United States. On Monday, the U.S. Department of Agriculture reported several more cases of the screwworm, following the discovery of its reemergence in Texas last week. One of these cases involved a dog in the neighboring state of New Mexico, a troubling sign of the parasite’s spread. The USDA has set up a website where people can report suspected cases. “We are working closely with our partners in New Mexico, Texas, and across the region to ensure we identify, contain, and respond to any potential cases as swiftly as possible,” said Dudley Hoskins, Under Secretary for Marketing and Regulatory Programs at USDA, in a statement. Beyond Texas The New World screwworm is a species of parasitic fly called Cochilomyia hominivorax. Unlike many other species, the fly’s maggot form prefers to feed on the living flesh of warm-blooded animals. The flies lay eggs on a host via open wounds or mucous membranes, and then the maggots use their screw-like bodies to burrow themselves deep into the animal. Along the way, the maggots’ sharp mouth parts chew through the host’s body, which can cause extensive, even life-threatening tissue damage.