Days after officials announced the New World screwworm fly had made a return to the U.S., with a case detected in a Texas calf, state and federal agricultural leaders announced a New Mexico dog has been infested with the sometimes-deadly pest.
The U.S. Department of Agriculture on Monday confirmed the case in a Lea County dog — the first such case in New Mexico, after months of surveillance by state and federal authorities.
The New World screwworm fly, largely eradicated from the U.S. for decades, poses a major threat to the livestock industry. Common in the Caribbean and Central America, its larvae burrow into the flesh of warm-blooded creatures, including livestock, pets, wildlife and, in rare cases, people. They feast upon healthy tissue, causing painful and putrid wounds.
The Department of Agriculture’s Animal and Plant Health Inspection Service on Wednesday confirmed the first U.S. screwworm infestation in years in a calf in La Pryor, Texas — about 100 miles west of San Antonio. Since then, the agency has confirmed two more bovine cases in Texas, plus the canine case in New Mexico.
The affected dog, a small-breed adult male that lives in Eunice, is being treated and recovering from the infestation, Dr. Samantha Holeck, state veterinarian with the New Mexico Livestock Board, said at a news conference Monday.
“We are having discussions with USDA about the next steps,” Holeck said. “Certainly, surveillance is at the top of the list, and mitigation strategies are being discussed.”
If a breeding population of flies is found in New Mexico, she added, the state may consider establishing an “infested zone” and increasing restrictions and inspection requirements for moving animals out of the area.
The dog’s infestation is believed to be an isolated case, according to the Department of Agriculture. Since the dog’s recent travel and exposure history remain unknown, however, authorities have initiated inspections of other animals in the dog’s home and increased outreach in the area to curb any additional spread.
“The key to success in controlling New World screwworm is early reporting and early detection and early treatment, and that will help New Mexico and the other states with this issue,” New Mexico Agriculture Secretary Jeff Witte said at the news conference.
“We are working closely with our partners in New Mexico, Texas, and across the region to ensure we identify, contain, and respond to any potential cases as swiftly as possible,” U.S. Agriculture Under Secretary Dudley Hoskins said in a statement.
The federal agency in recent months has ramped up efforts to breed and disperse sterile screwworm flies, which can’t produce the larvae that would pose a threat to warm-blooded critters. Meanwhile, the U.S. Food and Drug Administration has issued emergency use authorizations for medications to prevent and treat screwworm infestations in cattle, sheep, goats, horses, birds, dogs and cats.
Holeck emphasized the fly infestations aren’t expected to pose a risk to the U.S. food supply, given existing inspection requirements before and during slaughter, nor are they contagious or infectious like a disease.
“This is transmitted by the fly only,” she said. “The fly lays eggs around open wounds and fragile mucous membranes like the eyes. It is not transmitted from one person to another, from one animal to another.”
That means it’s important to keep an eye on livestock and pets, and report suspected cases of screwworm to a veterinarian or the New Mexico Livestock Board.
“Be vigilant,” Holeck said. “It’s really important to watch your animals, watch for any changes in behavior.”
