New Mexico agriculture officials on Monday confirmed the state’s first case of New World screwworm, detected in a Lea County dog, just days after the first incursion of the devastating parasitic fly in a south Texas calf.

The infested dog, who resides in Eunice, was originally mistaken for a Texas case after being diagnosed over the state line by an Andrews County veterinarian this weekend, New Mexico Agriculture Secretary Jeff Witte said in a virtual news conference Monday. The case is the fourth detected in the U.S. so far.

The pest, which has advanced rapidly through Mexico after being mainly contained in Central America for several decades, is named for the maggot’s behavior of feeding on live tissue.

The infestation of maggots causes severe wounds that can result in injury and deaths of pets, wildlife, livestock and — in rare cases — people. Before U.S. officials declared the fly eradicated in 1966, it cost the agricultural sector tens to hundreds of millions of dollars annually.

State and federal officials said they believe the Lea County dog is an “isolated case,” but said they will inspect additional animals in the dog’s home.

“This situation is evolving, and we expect new information to emerge as our investigation continues,” U.S. Department of Agriculture Under Secretary for Marketing and Regulatory Programs Dudley Hoskins said in a statement. USDA “is committed to sharing what we learn quickly, accurately, and transparently so animal owners and local communities have the information they need to stay vigilant.” Hoskins said the federal agency is working with state agencies in both New Mexico and Texas and across the region “to ensure we identify, contain, and respond to any potential cases as swiftly as possible.”

The dog, only described as a “small-breed male,” was still receiving treatment in Texas. In addition to the New Mexico dog case, the USDA reported an additional confirmed case Monday in a goat from Gillespie County in central Texas.

Witte said the state’s emphasis remains on early detection in order to request federal help to slow fly reproduction or additional supplies to treat the wounds.

“The sooner we can determine if we, in fact, do have New World screwworm in any area of the state, the faster we can bring in the resources, the sterile flies and the veterinary stockpile products to help treat the animals,” Witte said.

New Mexico Livestock Board State Veterinarian Samantha Holeck said as part of the investigation, officials will put out additional fly traps and determine if New Mexico has a population of breeding flies.

If so, the state may establish an “infested zone,” which would require increased inspections of animals to allow them to leave the area

“Remember this affects all warm-blooded animals, so it would be a pretty broad reach for us to try to be on the ground,” Holeck said. “But we want to work with folks in the area and have good, clear communication about what is needed to safely and efficiently move animals out of that area if needed.”

Suspected screwworm cases

Federal and state officials said to be on the lookout for animals with draining or growing wounds with maggots or egg masses; general signs of discomfort or irritability and lesions around the ears, nose and genitals.

“Treatment can be very successful if it’s caught early enough. If it’s left untreated, then certainly it can lead to death in these animals,” Holeck said.

New Mexico officials launched a one-stop website in mid-May to track potential New World screwworm cases in the state, offer resources for identifying the fly and the best contacts if an infestation is spotted.