Emergency Approval for Veterinary Drug to Treat New World Screwworm

The U.S. Food and Drug Administration has granted emergency authorization for an over-the-counter veterinary medication aimed at treating infections caused by the New World screwworm, a parasite that poses a serious threat to dogs and cats.

This decision follows reports from two states regarding infections: cattle and goats in Texas and dogs in New Mexico have been affected.

Remarkably, these incidents mark the first cases in animals since 2017, when a small outbreak was identified and subsequently eradicated in Florida, as stated by the United States Department of Agriculture (USDA).

The infection’s first instance this month was noted in a 3-week-old calf in Texas.

The FDA has indicated that the generic medication, Nitenpyram Tablets, can be utilized for treating infestations in dogs, puppies, cats, and kittens that weigh over 2 pounds and are at least 4 weeks old.

The New World screwworm is a type of fly that feeds on the tissues of warm-blooded animals and humans, according to the Centers for Disease Control and Prevention (CDC).

Infections typically occur when adult females are drawn to open wounds and other bodily openings like the eyes and mouth.

Each fly can lay about 200 to 300 eggs in these sensitive areas, leading to rapid hatching into maggots that burrow into the flesh. This dreadful condition is referred to as chriasis.

The FDA notes that nitenpyram is currently the only animal drug available specifically for New World screwworm treatment.

Acting FDA Commissioner Kyle Diamantas mentioned, “FDA has spent nearly a year conducting an expedited review to prepare for the arrival of New World screwworms in the United States.”

Nitenpyram is designed to act quickly, killing most larvae within hours after the initial dose, per FDA information. A second dose is recommended 6 hours later, and the dosage depends on the pet’s weight.

However, the FDA cautioned that nitenpyram tablets are not a preventative solution against New World screwworm disease or reinfection.

“After treatment with nitenpyram tablets, your veterinarian may need to physically remove any remaining live or dead larvae,” the FDA advises.

This process is best handled by a trained veterinary professional to reduce the risk of infection or additional tissue damage.