New World Screwworm

​The New World screwworm (Cochliomyia hominivorax) is a parasitic fly that lays its eggs in the open wounds and mucous membranes of warm-blooded animals, including livestock, pets, and in rare cases, humans.  The larvae, or maggots, feed on the living flesh of the host, which can lead to severe damage and potentially death if left untreated.  The U. S. eradicated the screwworm in 1966, but a recent northward progression of cases from Central America has renewed concerns.  A sterile insect technique, which involves releasing sterilized male flies to prevent the reproductive cycle, is a key tool in eradicating the pest.

COMMUNITY

• CDC:  New World Screwworm Fly Myiasis
• USDA:  New World Screwworm Fly Story Map  
• University of Florida:  Screwworm Fly
• New World Screwworm and Agriculture Employees
• New World Screwworm and Agriculture Producers

HEALTHCARE PROVIDERS

• CDC: New World Screwworm Health Advisory, Jan. 20. 2026 - Outbreak Moves into Northern Mexico
• CDC:  New World Screwworm Fly Myiasis
• CDC:  About New World Screwworm Myiasis
• CDC:  Clinical Overview of New World Screwworm Myiasis
• CDC:  Clinician Outreach and Communication Activity

LOCAL HEALTH DEPARTMENTS

• HHS:  Health & Human Services and United States Department of Agriculture Confirm Singular Traveler-Associated New World Screwworm Case; Precautionary and
• Proactive Surveillance Ongoing
• Maryland Dept. of Health:  Maryland Department of Health Confirm New World Screwworm Fly
• Interim Considerations for Advanced Readiness and Preparedness for New World Screwworm (NWS) infestations in Humans
• New World Screwworm Case Report Form

TESTING

• CDC:  DPDx – Laboratory Identification of Parasites of Public Health Concern