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Veterinary Entomology

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

USDA-APHIS - Screwworm.gov

US Animal Health Association

Centers for Disease Control

STATE RESOURCES

California Department of Food and Agriculture (CDFA)
- https://www.cdfa.ca.gov/ahfss/Animal_Health/screwworm/
University of California at Riverside
- https://murillolab.ucr.edu/screwworm
Florida Department of Agriculture & Consumer Services
- https://www.fdacs.gov/Agriculture-Industry/Pests-and-Diseases/Animal-Pests-and-Diseases/New-World-Screwworm
Texas Animal Health Commission
- https://www.tahc.texas.gov/emergency/nws.html
Texas A&M Agrilife Extension
- https://agrilifeextension.tamu.edu/new-world-screwworm
New Mexico State University
- https://screwwormnm.org/
University of Tennessee
- https://vectorvbdwatch.tennessee.edu/cochliomyia-hominivorax/

COMMODITY GROUP RESOURCES

AVMA
- https://www.avma.org/resources-tools/one-health/veterinarians-and-public-health/new-world-screwworm
NCBA
- https://www.ncba.org/education-resources/industry-updates-resources/new-world-screwworm-resources
Swine Health Information Center
- https://www.swinehealth.org/wp-content/uploads/2026/01/SHIC-Fact-Sheet-NWS-Considerations-for-Swine-1-2026.pdf
American Sheep Industry Association
- https://www.sheepusa.org/education-resources/animal-health/new-world-screwworrm-resources

Brown Dog Tick

The brown dog tick (Rhipicephalus sanguineus) is an important pest of dogs worldwide that occasionally will feed on humans. This tick is unique in that it can develop indoor populations, often reaching high levels. This tick is an important vector for several dog pathogens, including those causing canine ehrlichiosis and babesiosis. Recently, this tick has been shown capable of transmitting Rocky Mountain spotted fever in the southwestern US and nearby parts of Mexico.