The Maryland Department of Health has said a 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.
US cattle futures tumbled on concerns the pest will also strike livestock as ranchers criticised 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 US cattle-producing state, about $1.8billion, according to US estimates.
The Centers for Disease Control and Prevention confirmed the human case of screwworm on 4 August in a person who returned from travel to El Salvador, according to the US Department of Health and Human Services.
The agency announced the case after journalists 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.
'Tone deaf'
The nearly three-week delay between the confirmation of the case on 4 August and the US 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.
Screwworm has spread north in Mexico from Central America, prompting the US Department of Agriculture to halt imports of Mexican cattle in July.
The USDA has not responded to questions about the human case and what communications the agency had with the CDC.
