Basics of New World Screwworm

USDA is leading a national One Health response to keep New World Screwworm (NWS) out of the United States. Our whole-of-government effort is crucial to protect the U.S. livestock industry, economy, food supply, and public health. Find out more about NWS — including a description of the pest and its lifecycle, what to look for, how to prevent it, how it is treated, and the national response — at screwworm.gov.

How Conservation Practices Can Help Disrupt the NWS Life Cycle

The New World Screwworm life cycle can be disrupted with the help of conservation practices that provide surveillance and reservoir management, control the breeding environment, limit transmission, enhance biosecurity and containment, help with response and recovery, and control the growth environment.

Conservation Practices and Activities to Consider

Integrating NRCS conservation practices and activities can enhance farm readiness, protect livestock health, and strengthen national biosecurity. A list of conservation practices to consider is below.

• Conservation Evaluation and Monitoring Activity Feral Swine Damage Assessment (Code 297) - Manage and detect where feral swine are present, guiding NWS surveillance as feral swine are highly susceptible to NWS and they are a reservoir for spread.
• Access Control (Code 472) - Controlling access for the purpose of excluding animals can reduce movement of infested animals, prevent exposure to high-risk zones, and limit contact with wildlife vectors.
• Animal Mortality Facility (Code 316) - Appropriate handling and disposal of carcasses can reduce odors that attract flies and reduce larva development in animal tissue (although the new world screwworm flies prefer live tissue). This would help reduce fly breeding but won’t necessarily prevent infestation in live animals.
• Brush Management (Code 314) - Cleaning and thinning brush enhancing vegetative cover and wildlife habitat can reduce habitat for flies by improving airflow and creating an environment unfavorable to flies.
• Grazing Management (Code 528) - Facilitate livestock movement and monitoring as part of an integrated plan, including movement through desired safe or treatment areas.
• Livestock Shelter Structure (Code 576) - Improve distribution of grazing animals to enhance wildlife habitat, reduce over-used areas, or correct other resource concerns resulting from improper animal distribution that would attract flies, provide breeding habitat, or encourage infestation.
• Pest Management Conservation System (Code 595) - Monitoring and scouting pests to reduce injury to livestock. 

Steps You Can Take If You Suspect NWS on Your Operation