What vets need to know about New World screwworm (NWS)

New World screwworm (NWS) is a parasitic fly that causes serious disease (myiasis) in livestock, pets, wildlife, occasionally birds, and in rare cases, people.  It is most often detected in cattle, swine, horses, small ruminants, and dogs.  Although NWS was eradicated from the United States and Central America decades ago, it has resurged and was recently detected as far north as Mexico.  In May, U.S. Secretary of Agriculture Brooke L. Rollins suspended live cattle, horse, and bison imports from Mexico through U.S. ports of entry along the southern border as an additional measure to protect U.S. agriculture.