Arizona animal health officials are on high alert after confirming five cases of New World screwworm in the state. The infestations involve two horses, two dogs and one sheep located in the eastern and southeastern regions. While Yuma has reported no cases, the spread underscores the need for vigilance among pet owners, especially those with outdoor animals.
What is New World screwworm?
New World screwworm is a parasitic fly whose larvae feed on living tissue. Infestations can create serious, foul‑smelling wounds and may become fatal if not treated promptly. The condition is rare in the United States, but when it appears, rapid response is essential.
Emergency treatment authorized by the FDA
On November 3, the U.S. Food and Drug Administration granted emergency authorization for the use of Bravecto chewable tablets to treat screwworm infestations in dogs and puppies. Bravecto is already approved for flea and tick control, but this emergency use expands its application to address the parasitic larvae. The agency noted that the drug “may be effective when used as authorized,” and Merck Animal Health expects the specially labeled chews to reach veterinarians in early 2027.
Veterinary guidance for Arizona pet owners
Dr. Mindy Bemmerl, director of veterinary medicine at the Arizona Humane Society, emphasized that any dog can become infested, though outdoor pets in rural areas are at higher risk. “If they develop a wound that the owner doesn’t see right away because of the environment, that can be a source of infection,” she explained. She added that veterinarians are receiving updated guidance as the situation evolves and that other medications may also be viable options.
Pet owners should not attempt to treat suspected screwworm themselves. Instead, they should contact a veterinarian immediately if they notice visible maggots, foul‑smelling wounds, or any unusual skin lesions on their animals. Early veterinary intervention greatly improves outcomes.
Travel considerations for California
California has responded by tightening entry requirements for companion animals coming from states with active screwworm zones. Travelers must obtain a veterinary inspection, an electronic certificate that includes a screwworm statement, and an entry permit. Additional rules apply to animals arriving from infested zones, so owners should verify the latest requirements before crossing state lines.
How to protect your pets
- Inspect outdoor pets regularly for wounds or signs of maggots.
- Keep dogs and other animals indoors or in fenced areas when possible, especially during peak fly activity.
- Maintain up‑to‑date flea and tick preventatives, which can reduce the likelihood of fly exposure.
- Seek veterinary care at the first sign of a suspicious wound.
By staying informed and acting quickly, Arizona residents can help contain the screwworm threat and safeguard the health of their beloved animals.
Original reporting: azfamily KTVK/KPHO Phoenix (news) — read the source article.
