The New World Screwworm (NWS), a pest previously eradicated in the United States, was confirmed in
livestock and companion animal cases in Texas and New Mexico in June 2026 by the U.S. Department of
Agriculture (USDA) Animal and Plant Health Inspection Service.
New World Screwworm is a serious pest that can threaten livestock, pets, wildlife, and, in rare cases,
people, if it goes untreated. NWS larvae burrow into living tissue through open wounds or body openings,
with young animals like calves most susceptible. For livestock producers and owners of other warm-blooded
animals, the most important preventative measure is to inspect animals regularly. Animals recover from NWS
infection if it is detected and treated without delay. The Virginia Department of Agriculture and Consumer
Services (VDACS) advises animal owners to develop a preventative plan with your veterinarian, and stay
vigilant with your animals’ health. Consult a veterinarian immediately if an animal has a wound that looks
suspicious or is getting larger.
There is no threat to food safety in the U.S. as NWS infection does not make beef or other meats unsafe
to eat. Because the pest does not survive sustained temperatures of less than 46 degrees, it is unlikely
that NWS will become established in the Commonwealth of Virginia, though summer cases are possible.
Additional inspection requirements are now in place for the movement of animals leaving the infested
zone of the southern border states. Latest details on requirements and response can be found on the
dedicated federal website, screwworm.gov. Virginia’s standard
Certificate of Veterinary Inspection
requirements will continue, and producers and animal owners in the Commonwealth must comply with any
applicable national guidance.
The USDA NWS response has been in place for many years, steadily increasing as the pest has been tracked
migrating north through Central America since early 2025. NWS was eradicated from the U.S. in 1966, with
only a brief outbreak in the Florida Keys in 2017. The NWS population is combated with Sterile Insect
Technique, in which sterile male flies are bred and released into the environment to prevent the fly’s
population growth. As sterile fly production capacities are increased, it is anticipated that NWS will be
pushed back out of the U.S.
VDACS will continue to monitor the outbreak and advise Commonwealth animal owners and residents if any
further action is to be taken in the state. Questions about animal health in Virginia can be directed to
the VDACS Office of Veterinary Services at 804-786-2483 or vastatevet@vdacs.virginia.gov.
Visit screwworm.gov for additional NWS information
USDA
NWS Response Playbook
Phone: 804-786-2483
Email: vastatevet@vdacs.virginia.gov