Arizona Reports New World Screwworm Case as U.S. Battles Resurgence

Officials in Arizona confirmed a case of New World screwworm in Cochise County, marking the third state in the U.S. to report an incident. The screwworm, a parasitic fly, affects warm-blooded animals. A dog showed signs of infestation, and scientific tests confirmed the diagnosis.

Dr. Ryan Wolker, Arizona’s State Veterinarian, emphasized state readiness for this issue, detailing swift response measures. Historically, screwworms were virtually eradicated in the U.S. livestock. However, since June, the U.S. Department of Agriculture recorded 71 animal cases, including in Texas and New Mexico. A wildlife case was reported recently.

Screwworm larvae can cause severe wounds in animals by burrowing into living flesh. The Centers for Disease Control and Prevention assured that human infection reports are absent, maintaining a low risk for people.

The U.S. resumed importing some cattle from Mexico, a previous suspension following a screwworm case there in late 2024.