New World Screwworm: What Pet Owners Need To Know

A dog in Texas has tested positive for New World screwworm, a flesh-eating fly larvae that feeds on living tissue in warm-blooded animals. The case marks the first confirmed infection in the state in decades, reigniting fears about the parasite's potential to spread among pets and livestock. New World screwworm (Cochliomyia hominivorax) was eradicated from the United States in 1966 through rigorous control programs, but re-emerged in Florida in 2016 and now appears to have jumped to Texas. The infected dog, identified by local veterinarians, presented with a wound infested with maggots—a condition known as myiasis. Without prompt treatment, the larvae can burrow deeper, causing severe tissue damage, secondary infections, and death. The U.S. Department of Agriculture (USDA) has confirmed the case and is working with Texas Animal Health officials to trace the source and monitor for additional infections. The parasite is endemic in parts of South America and the Caribbean, and can spread through animal movement or accidental transport of flies. For pet owners, the threat is real but manageable: keeping wounds clean, using approved insecticides, and reporting suspicious infestations immediately are critical steps. Veterinarians emphasize that early detection is key, as treatment involves physical removal of larvae and application of topical medications. The broader concern extends to the livestock industry, where screwworm can cause millions in losses. A sterile insect technique (SIT) program, which releases sterile male flies to suppress reproduction, has been effective in Florida and may be deployed in Texas. The USDA is urging vigilance across the southern U.S., as climate conditions favor the fly's survival. This case underscores the vulnerability of modern animal health systems to re-emerging pathogens and the importance of sustained surveillance.