06/15/2026
New World Screwworm (NWS) is a flesh-eating parasitic fly (Cochliomyia hominivorax) whose larvae infest open wounds and feed on the living tissue of warm-blooded animals, including livestock, pets, wildlife, and in rare cases humans. The parasite can cause severe tissue damage, infections, and even death if left untreated.
NWS has recently reappeared, with confirmed animal cases reported in Texas and New Mexico in 2026. The outbreak is a major concern for the livestock industry because of its potential economic impact and threat to animal health. Animal owners are being urged to regularly inspect animals for wounds, maggots, or unusual lesions and report suspected cases to CDFA immediately. No cases have been identified in California as of now.
CDFA has recently released NWS entry requirements for animals entering California, found here: https://www.cdfa.ca.gov/ahfss/Animal_Health/screwworm/
For more information, please visit this USDA link for more information: https://www.aphis.usda.gov/livestock-poultry-disease/cattle/ticks/screwworm
