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National Invasive Species Information Center
U.S. Department of Agriculture

Screwworm

Scientific Name

Cochliomyia hominivorax (Coquerel) (ITIS; name is valid but unverified)

Common Name

New World screwworm, primary screwworm

Native To

South America and the Caribbean (CFSPH 2012)

Date of U.S. Introduction

Eradicated in the U.S. in 1966 (ARS 1992)

Means of Introduction

Could be reintroduced to the U.S. from an infested animal (CFSPH 2012)

Impact

Parasite that kills livestock and wildlife, particularly cattle (CFSPH 2012)

Current U.S. Distribution

Not currently established

Screwworm, larva(e)
Image use policy

Screwworm, larva(e)

Credit

Photo by Lesley Ingram

Source
Invasive.org.

Find more images

Spotlights

  • A New World Screwworm - A Story Map

    • USDA. Animal and Plant Health Inspection Service.

    • An interactive story map of the USDA's history of eradicating the infestation and the continuing efforts to keep screwworm out of the U.S.
      See related resource: Data Visualization Tools to explore plant and animal health management data and interactive story maps

  • Screwworm.gov

    • USDA. Animal and Plant Health Inspection Service.

    • New World screwworm (NWS) is a devastating pest. It can cause serious, often deadly damage to animals and people in areas where the pest spreads. While NWS is present in parts of South America—where infections in animals and people continue to occur—it was eradicated from the United States decades ago. In recent years, NWS has moved northward through Central America and Mexico. 

      USDA is leading an aggressive national, One Health response to keep NWS out of our country.

Videos

All Resources

View and Filter All Screwworm Resources

Selected Resources

The section below contains highly relevant resources for this species, organized by source.

Partnership
Federal Government

  • Livestock and Poultry Disease - New World Screwworm

  • Screwworm Eradication Program Records

    • USDA. ARS. National Agricultural Library.

    • The Screwworm Eradication Program Records, housed in Special Collections of the National Agricultural Library (NAL), documents one of the greatest success stories in the history of American agriculture. Led by the United States Department of Agriculture (USDA), the eradication of the screwworm from the United States, Mexico, and most of Central America marked a major victory over the destruction of domestic and wild animals by an insect which feeds only on the living tissue of warm-blooded animals.

      The Screwworm Eradication Program Records document research and eradication efforts from the 1930s through 2000. These materials include correspondence, plans, reports, scientific papers and manuscripts, publications, raw research data and research analyses, livestock producer information materials and reports, cooperative agreements, photographs, maps and artifacts.

State and Local Government
Academic
Citations