06/18/2026
As you may have heard, USDA confirmed the presence of New World Screwworm (NWS) in the United States on June 3, 2026.
What is New World Screwworm?
New World Screwworm (NWS) is the larvae (maggots) of the parasitic fly Cochliomyia hominivorax. NWS does not spread from animal to animal or from animals to people. Rather, infestation occurs when a fly lays eggs on an animal and the maggots enter through any break in the skin—including surgical sites, tick bites, umbilical areas, mucous membranes, and body openings.
Because NWS larvae feed on living tissue, untreated wounds can rapidly worsen, causing severe pain, infection, and potentially death within days to weeks. Early detection is critical for protecting your animals.
What signs should I look for?
Carefully observe your animals for any unusual changes, especially open wounds. Possible signs of infestation include:
• Visible maggots in wounds or body openings (nose, ears, mouth, ge****ls)
• Bloody discharge or foul, decaying odor from wounds
• Behavioral signs of pain or distress such as irritability, depression, head shaking, reduced appetite, or isolation.
If you are located near confirmed NWS cases, take extra precautions:
If you suspect NWS in any animal—domestic or wildlife—contact your veterinarian immediately. USDA teams are working diligently to limit the spread, and rapid reporting greatly improves our ability to respond.
Your prompt action can significantly reduce pain, prevent complications, and protect other animals. Is treatment available?
Yes, NWS can be treated, but immediate intervention is essential. Animals undergoing treatment will require quarantine, and environmental treatment may also be necessary. Your veterinarian will guide you through each step to ensure the best possible outcome for your animals’ health and welfare.
Where can I get more information?
USDA maintains several helpful resources:
screwworm.gov – Central source for U.S. Government regarding New World Screwworm
New World Screwworm Fact Sheet1 – Facts vs myths about New World Screwworm
Current status2 – USDA website updated with latest confirmed detections
Learn how the U.S. Government prevents New World screwworm and what to know about risks, surveillance, sterile-fly control, travel, and more.
