New World Screwworm
New World Screwworm first entered the United States in June 2026.
Federal and local agencies are composing a unified effort around early detection, rapid communication and coordinated action regarding New World Screwworm to monitor and contain the spread. New World Screwworm can infest livestock, pets, wildlife, occasionally birds, and in rare cases, people.
New World Screwworm affects livestock, pets, wildlife, occasionally birds and in rare cases, people. The disease is most often detected in cattle, swine, horses, small ruminants and dogs.
Female flies lay eggs on living animals at the edge of wounds or mucous membranes such as nostrils, ears, eyes, mouth or genitals. Eggs hatch and the larvae burrow into tissue and continue to feed and grow. As the larvae feed on the host, the wound becomes larger and deeper. The larvae then fall from the wound, bury into the ground to pupate and emerge as new flies looking to breed and infect a new host.
To report a possible New World Screwworm infestation among livestock, please call the Arkansas Department of Agriculture at 501-823-1746.