A case of New World screwworm, a parasitic fly whose larvae feed on living flesh, has been detected in Texas; the USDA is investigating. The condition is rare in humans but can be fatal in animals if untreated.

Newsweek

Wall Street Journal

Reuters

New York Post

Screwworm's maggots typically enter an animal through an open wound and feed on its living flesh, eventually killing the host if left untreated. In rare cases, they will infect humans.