New World screwworm prompts US emergency drug approval and Colorado movement restrictions

The U.S. Food and Drug Administration granted emergency use authorization for nitenpyram tablets, an over‑the‑counter veterinary drug, to treat New World screwworm infestations in dogs, puppies, cats and kittens weighing at least 2 lb and older than 4 weeks. The approval follows recent detections of the parasite in cattle and goats in Texas and in dogs in New Mexico, marking the first animal cases since a 2017 outbreak. Nitenpyram kills larvae within hours; a second dose is recommended six hours later, and veterinary removal of remaining larvae may be required.

In Colorado, the Department of Agriculture adopted an emergency rule that tightens inspection and movement requirements for all warm‑blooded animals entering the state from designated infested zones. Animals from a 20‑km radius around confirmed detections must carry a Certificate of Movement, undergo veterinary inspection within five days, and have open wounds treated before transport. Pets such as cats and dogs face additional inspection protocols. The rule aims to prevent the spread of New World screwworm into Colorado while confirming that the parasite poses no food‑safety risk to the U.S. food supply.