An Old Threat Making Headlines Again

If the New World screwworm has been around for years, pet owners are asking a reasonable question: Why is it called 'New World' if there's nothing new about it? The name doesn't mean the parasite was recently discovered. Veterinarians and livestock producers have dealt with screwworms for generations. The term 'New World' simply refers to the part of the world where this species originated- North and South America. There is also an 'Old World' screwworm found in parts of Africa, Asia, and the Middle East. Federal officials have confirmed recent U.S. animal cases in the current outbreak, including livestock and a dog in New Mexico near the Texas border. That news leaves pet owners like me wondering what this means for the animals in their own homes, yards, farms, and barns. Despite its name, a screwworm is not actually a worm. It is the larval stage of a fly. Unlike ordinary maggots that feed mostly on dead tissue, New World screwworm larvae feed on living tissue. That is why veterinarians and agricultural officials take them so seriously. The fly does not create the original wound. It looks for an existing problem. Adult female flies are attracted to the odor, moisture, blood, drainage, or irritated tissue associated with wounds and body openings. They may lay eggs in or near that area. Once the eggs hatch, the larvae begin feeding on living tissue, which can cause the wound to enlarge and worsen quickly. For pet owners, this matters because many everyday problems can create an opening. A tick bite. A hot spot. A scratch. A surgical incision. An ear infection. Skin rubbed raw from licking. Irritation around the nose, mouth, genitals, or another moist area can also become a concern. Dogs, cats, rabbits, horses, livestock, wildlife, small mammals, and even birds can be affected if they have wounds or vulnerable tissue. Outdoor pets, barn cats, hunting dogs, livestock guardian dogs, and animals recovering from surgery deserve extra attention, especially in areas whe...