By Basant El-Faramawy
A dog in Arizona has been infested with New World screwworm, a parasitic fly that consumes living tissue, marking the third U.S. state to report the pest since its reappearance in June, the U.S. Department of Agriculture announced Wednesday.
Outbreak expands to Arizona
The case was detected in Cochise County, which borders Mexico, according to the USDA. The Arizona Department of Agriculture said the dog had a wound on its back infested with maggots consistent with screwworm, and laboratory testing confirmed the infestation. The animal is receiving veterinary care.
Federal and state response
State Veterinarian Dr. Ryan Wolker said officials had been preparing for this possibility and are acting swiftly. The USDA has restricted animal movement within a 20-kilometer (12-mile) zone around the case, increased surveillance of live animals, and is releasing sterile flies to combat the parasite.
Spread from Mexico
The USDA halted livestock imports from Mexico last year to prevent screwworm entry after the pest advanced north through Mexico and Latin America. The agency detected screwworm in a calf in Texas in June, followed by additional cases in Texas and New Mexico. As of Wednesday, 71 cases have been reported since June, with 18 active infestations, up from only two active cases a month earlier.
Symptoms and risks
New World screwworm larvae infest wounds or body openings of warm-blooded animals, causing painful, worsening sores, foul odor, and bleeding. The Centers for Disease Control and Prevention notes that humans can also be affected.
