Maryland Screwworm Patient Recovered; Ranchers Criticize CDC Secrecy

By and | August 26, 2025

The patient with the first human infestation of travel-associated New World screwworm in the United States has recovered from the flesh-eating parasite, and there was no sign of transmission to other people or animals, the Maryland Department of Health said on Monday.

U.S. cattle futures tumbled on concerns the pest will also strike livestock as ranchers criticized a lack of transparency about the case, following exclusive reporting by Reuters.

Screwworms are parasitic flies whose females lay eggs in wounds on any warm-blooded animal. An outbreak could cost the economy in Texas, the biggest U.S. cattle-producing state, about $1.8 billion, according to U.S. estimates.

The Centers for Disease Control and Prevention confirmed the human case as screwworm on August 4 in a person who returned from travel to El Salvador, according to the U.S. Department of Health and Human Services.

The agency announced the case on Sunday after Reuters reported earlier in the day on emails from beef industry officials on a CDC-confirmed case in a person in Maryland who had traveled to the United States from Guatemala.

The nearly three-week delay between the confirmation of the case on August 4 and the U.S. government’s disclosure erodes trust that public agencies need to identify and fight potential screwworm outbreaks, said Neal Wilkins, CEO of conservation and cattle group East Foundation.

“It will cause many producers and land owners, wildlife managers, to simply begin to believe that they’re not being fed the whole story,” he said. “It’s irresponsible and tone deaf for them to have done this.”

Maryland’s health department said the patient was a resident of the state but did not respond to questions about the country to which the person traveled or the timing of the case. An HHS spokesperson did not address the discrepancy on the source of the human case on Sunday.

Feeder cattle futures FCU25 fell at the Chicago Mercantile Exchange after cattle and beef prices set records this year because the nation’s herd shrank to its smallest size in 70 years.

Screwworm has spread north in Mexico from Central America, prompting the U.S. Department of Agriculture to halt imports of Mexican cattle in July.

USDA Secretary Brooke Rollins did not mention the human case when she traveled to Texas on August 15 to announce that the agency would spend up to $750 million to build a Texas facility to produce sterile flies to combat screwworm. The agency has not confirmed cases in animals this year. The USDA has not responded to questions about the human case and what communications the agency had with the CDC.

Last week, an executive of industry group Beef Alliance sent emails to about two dozen people, informing them the CDC had confirmed a case in Maryland in a person who had traveled to the U.S. from Guatemala, according to a source. Beef Alliance has not responded to requests for comment.

U.S. cattle producers’ association R-CALF USA said on Monday there should be an investigation if government officials shared information about the case with select industry members.

“Without transparency and symmetrical information dissemination to all industry participants there can be no trust between industry participants and the government,” the association’s CEO, Bill Bullard, said.

(Reporting by Tom Polansek in Chicago and Leah Douglas in Washington; Additional reporting by Heather Schlitz in Chicago and Cassandra Garrison in Buenos Aires; Editing by Stephen Coates)

Topics Maryland

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