The FDA has cleared Capstar (nitenpyram) tablets, plus the generic version, to prevent and treat New World screwworm infestations in dogs and puppies. The emergency authorization, announced September 3, gives owners the first prevention option for this parasite. Before this, only treatment products existed.
New World screwworm is a fly larva that burrows into wounds and body openings. It sounds like a faraway problem, and for most American dogs it is. Confirmed cases sit in a limited geographic region, and the FDA says most dogs in the United States are at low risk right now.
The dogs that need attention are the ones that live in, travel to, or return from affected areas, including some countries south of the U.S. border. For those dogs, watch for visible maggots or a foul odor coming from a wound, eye, ear, nose, or mouth. Either sign means an immediate vet visit. The tablets are sold over the counter in two sizes and dosed by weight, and dogs must weigh at least two pounds and be at least four weeks old.
What this means for your dog: probably nothing today. Skip the panic stockpile unless you are in or headed to a screwworm zone. If your dog travels to one, ask your vet about preventive dosing and check skin and ears after the trip. The FDA explained the decision in its September 3 announcement, covered in detail at dvm360, and the USDA keeps a running map of confirmed cases.