Arizona confirms first dog infection with New World screwworm
Officials in Cochise County identified the parasite in a canine on Monday, marking the third U.S. state to report an animal case.
By Nathaniel Hayes ·
The Arizona Department of Agriculture confirmed on Wednesday that a dog in Cochise County has been diagnosed with New World screwworm. This marks the first animal case in the state and the third in the United States, following earlier reports from Texas and New Mexico.
A local veterinarian examined the canine on Monday and discovered a wound on its back that was heavily infested with maggots. Laboratory testing confirmed the larvae were consistent with New World screwworm. The animal is currently under veterinary care while officials gather more information from the owner and the attending vet.
Dr. Ryan Wolker, the state veterinarian, said the department has been preparing for this possibility for a long time. He noted that extensive outreach and surveillance allow producers, vets, and pet owners to identify and report suspected cases quickly. This preparation is enabling the state to move swiftly to protect animal health.
The USDA is responding by establishing an infested zone and increasing surveillance in the area. The agency is also performing outreach to local partners. AZDA is requesting the release of sterile flies in the region to suppress the population and prevent the pest from becoming established.
New World screwworm is a parasitic fly that feeds on live tissue. The larvae, or maggots, use sharp mouth hooks to screw into the animal's tissue, causing extensive damage and often leading to death. The CDC notes that while the parasite can infest livestock, pets, and wildlife, it rarely affects humans. No human cases have been reported in the U.S. this year. The last domestic case involved a Maryland resident who returned from travel to El Salvador last year.
The parasite was eradicated in the U.S. for decades using a technique that involves sterilizing male flies and releasing them to mate with females until the population dies out. Cases among livestock have migrated up through the southern border over the past year. The CDC advises that people who travel to outbreak areas, spend time around livestock, sleep outdoors, or have open wounds are at greater risk.
