Authors: Marcus E. Blum, James C. Cathey, Roel R. Lopez, Parr Rosson, Sarah Fuller, Hunter Reed, and Kory Gann

The New World screwworm (NWS) Cochliomyia hominivorax, was eradicated from the U.S. in 1966 and has been limited to isolated outbreaks, including in 1976 in Texas and 2016 in Florida. Due to its recent northward movement through Central America and Mexico, it is once again an emerging threat to Texas.

These parasitic flies lay their eggs in or near wounds and the mucous membranes of living mammals. After hatching, the larvae burrow into the wounds and feed on live tissue — a condition known as myiasis. These wounds can result in rapid health decline and death, especially in free-ranging wildlife that do not receive veterinary care and cannot be closely monitored like livestock.

Texas is home to more than 100 mammal species that may be at especially high risk if this fly re-establishes itself here, including more than 5 million white-tailed deer. In addition to ecological and aesthetic value, native wildlife are a key contributor to the state economy. A study by the Texas A&M Natural Resources Institute found the management and hunting of white-tailed deer alone contributes more than $9 billion to the Texas economy every year.

The following information provides both urban and rural Texans with the knowledge needed to monitor, detect and report signs of NWS infestations to help protect wildlife ranging from squirrels and coyotes to white-tailed deer, mule deer and black bear.