USDA Confirms New World Screwworm in U.S. as Infestations Rise to Five Animals

The U.S. Department of Agriculture said the New World screwworm has been confirmed in animals in the United States, with the number of animals infested by the parasitic fly’s larvae rising to five.

“Three more cases of the New World screwworm have been confirmed, including one outside the main cluster in Texas, demonstrating the difficulty of stopping a resurgent pest that could devastate the nation's cattle industry, the U”

ABC

Euronews reported that the first infestation was confirmed last week in Texas and that the affected animals include three calves and a goat in Texas, plus a dog in the neighboring state of New Mexico.

ABC

The Iowa Department of Agriculture and Land Stewardship urged livestock producers and pet owners in Des Moines, Iowa to watch for signs of New World Screwworm after cases were found in Texas livestock and a dog in New Mexico.

In Texas, the USDA’s response has included quarantine measures, with the Iowa department saying people bringing livestock or companion animals into Iowa from an infested zone should contact the state animal health official in the state of origin for movement requirements and isolate imported animals from the rest of the herd for at least two weeks.

The USDA and state officials set up quarantine zones to slow the parasite’s advance, with the Iowa Department of Agriculture and Land Stewardship asking caretakers to routinely check animals for open wounds.

KWWL said that if maggots are found in an open wound on any warm-blooded animal, people should report it immediately to IDALS at 515-281-5305 or [email protected].

Abilene Reporter-News

AP reported that officials have set up a 12-mile (20-kilometer) quarantine zone in each case to try to slow the parasite’s advance, and it said there are now five confirmed cases: three calves and a goat in Texas and a dog from neighboring Lea County, New Mexico.

AP also quoted University of Florida entomologist Edward Burgess saying, "When that first case is seen, everyone is being vigilant and their eyes are on it more intensely," and it added that there is a 24-hour screwworm hotline and a website and map for reported cases.

Florida officials moved to enact emergency rules as the outbreak threatened cattle, with the Tallahassee Democrat saying the risk to humans is low while federal and state officials are in full swing in southwest Texas, New Mexico and beyond.

Tallahassee Democrat quoted Dr. Sally DeNotta saying, "I think it's going to have pretty substantial economic impacts on the livestock industry in the United States," and it tied the concern to a livestock industry already at a 75-year low for herd counts.

The same article cited a 2025 USDA report estimating that a 2024 outbreak of the New World screwworm would be a $732 million loss for the Texas livestock industry valued at $24.9 billion that year.

Euronews said the larvae do not transmit from person to person and that the risk to the population is very low, while also warning that people can be at risk if they travel to zones where the flies are present and pass long periods outdoors during the day, especially if they sleep outside.