Arizona animal-health officials have confirmed the state's sixth case of New World screwworm — an infection in a domestic horse near Pearce, in southern Cochise County — and have drawn a new mandatory Infested Zone around the area, the Arizona Department of Agriculture (AZDA) said. The case was confirmed on Tuesday, November 10, 2026, and reported on November 11. The horse had no known travel history, according to the department, and the property sits roughly five miles from the site of Arizona's first confirmed case, a dog near Elfrida whose infection was announced on October 28 — an earlier detection Awaaz Punjab covered when the outbreak first reached the state.
Around every confirmed detection, officials establish a mandatory 20-kilometre (12.4-mile) Infested Zone. Inside the new Pearce zone, no animals may leave until movement restrictions are lifted or the State Veterinarian authorises a move under the U.S. Department of Agriculture's (USDA) New World screwworm playbook, and the self-inspection procedure owners normally use is suspended while the zone is active, AZDA said. The department's live outbreak page lists six confirmed cases statewide — two in dogs, three in horses and one in a sheep — across three active response areas in Cochise, Graham and Greenlee counties.
Arizona's earlier five cases were a dog in Graham County, a sheep and a horse in Greenlee County, and a dog and a horse in Cochise County. The new Pearce horse is the third equine case. What makes this detection more concerning to officials is the absence of travel: a horse that has not been moved still became infested, which points to screwworm flies being present locally in southern Cochise County rather than the parasite arriving only inside an animal brought from somewhere else.
What the screwworm is, and why ranchers fear it
The New World screwworm is the larva of the fly Cochliomyia hominivorax. Unlike ordinary maggots, which feed on dead tissue, screwworm larvae burrow into the living flesh of warm-blooded animals — cattle, horses, sheep, dogs and wildlife — and, in rare instances, people. An untreated infestation can be severe and potentially fatal to the animal. The parasite was once eradicated from the United States, spread north through Mexico again from 2023, and was reintroduced into the United States in June 2026 in Texas and New Mexico, according to the Florida Department of Agriculture's outbreak summary. Arizona's first confirmed case followed on October 28, 2026.
The rules inside a zone are strictest at the property where an infested animal is found. Under the federal playbook Arizona is following, explained by Arizona Farm Bureau with the department's assistant state veterinarian Devon Kartchner, an infested animal itself is quarantined on its home property for 21 days or until its wounds have fully healed. Healthy animals on the same property can still move after inspection. Animals elsewhere in the zone can move freely inside it, but cannot leave without a movement permit and an inspection by a state livestock inspector or licensed veterinarian, and healthy livestock typically receive preventive treatment before they travel. A zone is expected to stay in place for at least 84 days — about four screwworm life cycles — after the last detection, and the clock resets with every new case, which means the Pearce confirmation extends restrictions in southern Cochise County into 2027 if no further case is found.
What it means for livestock haulers and ranch families
For the trucking readers who haul livestock through the Southwest, the practical effect is paperwork and inspections at exactly the wrong end of the year. Land Line Media, the OOIDA publication, reported on November 11 that screwworm cases have been confirmed in Arizona, New Mexico and Texas since November 6 and that drivers transporting livestock or poultry out of infested zones should expect increased inspections plus permit and documentation requirements; dairy calves face a pre-movement inspection and treatment, with a veterinary inspection valid for five days. Florida has gone further, requiring advance movement certificates for warm-blooded animals that have been in a designated infested zone, and Canada's food inspection agency has restricted live-animal imports from Arizona, where the first detection was confirmed on October 31.
On the ground in Cochise County, the pressure is economic as well as veterinary. Movement restrictions can hold up livestock sales and shipments for ranching families already working through drought and water uncertainty, and the expanded zone underscores why officials are asking for fast reporting: a case found early limits how far the flies — and the zones — spread. USDA is supporting the response with sterile-fly releases and construction of a sterile-fly dispersal facility in Douglas, Arizona, AZDA said, a technique that works by flooding an area with sterile male flies so wild females produce no offspring.
Inspect animals daily for open wounds. Report any wound that appears infested with maggots consistent with screwworm to the Arizona Department of Agriculture at diseasereporting@azda.gov or 602-542-4293 (Monday to Friday, 8 a.m. to 5 p.m.). Hunters and recreationists who find apparently infested wildlife should call the Arizona Game and Fish Department at 623-236-7201 and note the GPS coordinates. Do not move animals out of an Infested Zone without State Veterinarian authorisation.
What happens next
Officials will keep testing suspect wounds around Pearce and across the three existing zones, and each new confirmed case would reset the 84-day clock and could redraw zone boundaries. The state says it is coordinating with USDA, neighbouring states and Mexican counterparts on the regional response. For ranchers, horse owners and haulers, the next facts to watch are whether a seventh Arizona case appears, whether the Pearce zone boundaries change, and whether movement permits keep animals and trucks moving through the winter sales season. Awaaz Punjab will update this story as AZDA posts new case counts.