Screwworm Cases Reach 71 Across US

REDFIELD, Iowa (DTN) -- New World screwworm (NWS) cases have seen an uptick over the past several days near the southern U.S. border, with the first case found in Arizona in a dog on Wednesday, Oct. 28.

Also on Wednesday, two cases were found in New Mexico, in a dog and a domestic cat. On Tuesday, Oct. 27, a dog in New Mexico and another in Texas were found to have NWS. Two cases in New Mexican cattle were found on Saturday, Oct. 24, and Monday, Oct. 26. This leads to 71 total cases of NWS in the U.S., with 18 currently active.

USDA's Animal and Plant Health Inspection Service (APHIS) confirmed the latest case after samples from the dog were tested and confirmed at the APHIS National Veterinary Services Laboratory in Ames, Iowa.

USDA reminds animal owners, in infected areas especially, to inspect animals daily for draining or enlarging wounds, maggots or egg masses in wounds, signs of discomfort or irritability, or lesions around body openings. If any are suspected, a veterinarian, state animal health official or USDA should be contacted immediately.

The phased opening of ports of entry on the Mexico-U.S. border has continued for cattle trade. After the border was closed in July 2025 due to the spread of NWS northward in Mexico, the border was closed until Aug. 24, 2026, when the Douglas, Arizona, port of entry opened to cattle trade.

U.S. Secretary of Agriculture Brooke Rollins promised the phased opening to continue with additional ports of entry opening one per month as long as NWS wasn't spreading out of control.

"Protecting the United States from NWS and pushing this pest out of Mexico and back to the Darien Gap is a top priority at USDA," said Rollins in a news release prior to the first port of entry opening. "The closure of the Southern ports of entry for the last year has been a tough but necessary action to control the spread of NWS in Mexico and protect the American livestock industry. Thanks to the work across the federal government as well as state, local, and industry partners, it is now safe to reopen the Douglas, Arizona, port in 30 days to resume the hundreds year old movement of cattle."

Sept. 24 marked the first day of cattle movement across the Santa Teresa, New Mexico, port of entry. The Columbus, New Mexico, port of entry opened for cattle trade on Oct. 26, which was the same day for equine movement to start at the Santa Teresa, New Mexico, site.

If conditions continue to support safe trade and all inspection requirements are met, USDA plans to reopen the Nogales, Arizona, port of entry to cattle imports on Nov. 30.

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Editor's Note:

For more DTN coverage of the New World screwworm threat and the response by the government and livestock industry, visit our Spotlight on New World Screwworm page at https://www.dtnpf.com/….

Jennifer Carrico can be reached at jennifer.carrico@dtn.com

Follow her on social platform X @JennCattleGal

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