STORY: The first case of flesh-eating screwworm in a human in the United States this year has been identified in a person in Maryland who had traveled from Guatemala.The parasite eats cattle and other warm-blooded animals alive...... and an outbreak has escalated and moved northward from Central America and southern Mexico since late last year.State veterinarians learned about the human case in Maryland during a call last week with the U.S. Centers for Disease Control and Prevention, according to a source.South Dakota's state veterinarian told Reuters on Sunday that she was notified of the case within the last week .......but complained that officials at the CDC "weren’t forthcoming" at all about the information.CDC and Maryland Department of Health spokespeople did not immediately respond to requests for comment.Screwworms are parasitic flies whose females lay eggs in wounds on any warm-blooded animal.Once the eggs hatch, hundreds of screwworm larvae use their sharp mouths to burrow through living flesh, eventually killing their host if left untreated.They rarely infect humans - and treatment is onerous, involving removing hundreds of larvae and thoroughly disinfecting wounds.Screwworms were eradicated from the United States in the 1960s when researchers began releasing sterilized male screwworm flies that mate with wild female screwworms to produce infertile eggs.The USDA has estimated a screwworm outbreak could cost the economy in Texas, the biggest U.S. cattle-producing state, about $1.8 billion in livestock deaths, labor costs and medication expenses.The U.S. typically imports over a million cattle from Mexico a year to fatten in feedlots and process into beef.The Maryland case and lack of transparency around it could also present a political challenge for U.S. Department of Agriculture Secretary Brooke Rollins, who pledged repeatedly to keep screwworm out of the country.Authorities have set traps and sent mounted officers along the border.But it has faced criticism from some cattle producers and market analysts for not acting sooner and pursuing increased fly production.For now, the sole operating plant producing sterile screwworms is in Panama City.New facilities in Texas that Rollins announced in June would need two to three years to come online.