Screwworm Information
New World screwworm (NWS) is a serious pest of livestock and wildlife.
This invasive pest we previously eradicated from the United States, but has recently been reintroduced (June 2026). Website links below provide information on screwworm, including prevention and treatment for screwworm. Treatment and prevention, as well as reporting requirements, often vary by state - contact animal health officials in your state for state-specific requirements and recommendations.
FEDERAL RESOURCES
STATE RESOURCES
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California Department of Food and Agriculture (CDFA)
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University of California at Riverside
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Florida Department of Agriculture & Consumer Services
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Texas Animal Health Commission
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Texas A&M Agrilife Extension
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New Mexico State University
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University of Tennessee
COMMODITY GROUP RESOURCES
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AVMA
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NCBA
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Swine Health Information Center
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American Sheep Industry Association
Chicken Lice
There are many different species of lice that can infest chickens. These include the chicken body louse (Menacanthus stramineus), shaft louse (Menopon gallinae), fluff louse (Goniocodes gallinae), wing louse (Liperus caponis), and chicken head louse (Cuclotogaster heterographus). Of these, the chicken body louse is the best known and probably most common species. All of these lice are permanent ectoparasite of domestic chickens, meaning they complete their entire life cycle on the host. The chicken body louse can reach problematic levels regardless of housing or production type (caged, cage-free, free-range, or backyard poultry). The other listed species are rare or unknown to infest commercial poultry, but have been documented on backyard chickens in a recent survey of backyard poultry in southern California, and past surveys of backyard poultry worldwide.





