Flesh-Eating Flies Return: FDA Authorizes Emergency Pet Treatment

The New World screwworm, a parasite whose larvae consume live flesh, has re-emerged in the United States after decades thought eradicated. Seven cases have been confirmed recently, primarily in Texas and New Mexico, affecting mammals such as cows, goats, and dogs. In response, the U.S. Food and Drug Administration has authorized the emergency use of Nitenpyram tablets, a flea treatment, for dogs and cats at least four weeks old and weighing at least two pounds.

These metallic-green flies lay eggs in open wounds, and their larvae rapidly enlarge the wound, which can be lethal if untreated. This re-infestation poses a significant threat to the livestock industry, with potential economic impacts estimated to reach a billion dollars internationally. Containment strategies include releasing sterile flies to disrupt breeding cycles, a process that has involved significant government investment.

Pet owners are urged to monitor their animals for signs of infestation, including unusual behavior, wound discharge, and foul odors. While most cases involve livestock, all warm-blooded animals, including pets, are susceptible. Veterinarians recommend immediate consultation if screwworm infestation is suspected, and professional removal of larvae may be advised after medication.

This resurgence marks a significant concern, as screwworms were considered eradicated in the U.S. from the 1960s until these recent detections. The U.S. government is employing an aggressive approach to control and eradicate the pest, viewing the FDA's authorization as a crucial tactical tool in the ongoing containment strategy.